Hydroponic plants need the same 17 essential elements as soil-grown plants, and because there is no soil to buffer or resupply them, all 14 mineral nutrients have to be dissolved in the water you feed.[1][2] Six are macronutrients used in larger amounts, nitrogen, phosphorus, potassium, calcium, magnesium, and sulfur, and eight are micronutrients needed in trace amounts, iron, manganese, zinc, copper, boron, molybdenum, chlorine, and nickel.[1][2] You manage the solution with two separate dials: pH, held for most crops between about 5.5 and 6.5 so those nutrients stay chemically available, and electrical conductivity (EC), which reads total dissolved salts and tells you the overall strength of the feed rather than the balance of any single nutrient.[3][8][6] Freshly mixed solutions usually run an EC of roughly 1.5 to 3.5 dS/m, started low for young plants and raised as they mature, with leafy greens near the bottom of that band and fruiting crops like tomato at the top.[4][6][3] Parts per million (PPM) is just EC converted by a fixed factor, so a reading only means something once you know whether the meter uses the 500 or the 700 scale.[7]
\n","summary":"Hydroponic feeds must supply all 14 mineral nutrients directly, since there is no soil reserve. Six macronutrients (N, P, K, Ca, Mg, S) and eight micronutrients (Fe, Mn, Zn, Cu, B, Mo, Cl, Ni) do the work. A pH near 5.5 to 6.5 keeps them available, while EC sets feed strength, roughly 1.2 to 1.8 for leafy greens and 2.0 to 3.5 for tomato. PPM is EC times a fixed factor, so the 500 and 700 scales report different numbers for the same water.","publishedAt":"2026-07-23T15:59:27.21","verifiedAt":"2026-07-18T00:00:00","editorialStatus":"APPROVED","lastReviewedAt":"2026-07-18T00:00:00","nextReviewDueAt":"2026-10-18T00:00:00","templateVersion":"v2","aliases":["what nutrients do hydroponic plants need","hydroponic nutrient requirements","macronutrients and micronutrients for hydroponics","how to manage pH in hydroponics","how to manage EC in hydroponics","hydroponic pH and EC target ranges","what is the ideal pH for hydroponics","hydroponic PPM 500 vs 700 scale","EC to PPM conversion hydroponics","hydroponic nutrient solution pH and EC guide","essential elements for hydroponic plants","how to adjust pH and EC in a hydroponic reservoir"],"confidenceScore":90,"confidenceLabel":"High","canonicalUrl":null},"contributor":{"id":"ec39deab-44fe-48d8-9029-fefe993ab85a","slug":"answer-stack","displayName":"AnswerStack","websiteUrl":null},"contributorOrganizationProfile":{"entityId":"ec39deab-44fe-48d8-9029-fefe993ab85a","legalName":null,"description":null,"websiteUrl":null,"imageUrl":null,"slogan":null,"subtitle":null,"facts":[],"coiNote":null,"foundingDate":null,"numberOfEmployeesText":null,"contactPoint":null,"address":null,"headquartersText":null,"organizationType":null},"contributorPerson":{"slug":"answerstack-editorial-team","displayName":"AnswerStack Editorial Team"},"sections":[{"id":"0aee7cfd-6491-40a8-9665-efae690e6661","sectionKey":"overview","sectionType":"markdown_section","heading":"What nutrients do hydroponic plants need, and how do you manage pH and EC/PPM?","introMarkdown":"Hydroponic plants need 17 essential elements, the same set every plant uses, but three of them, carbon, hydrogen, and oxygen, come free from air and water, which leaves 14 mineral nutrients that you have to deliver in the solution.[1][2] In soil, clay and organic matter hold a reserve of those minerals and release them slowly, but a soilless system has no such buffer, which is why the makeup of the nutrient solution and steady monitoring matter more here, and why a problem can appear in the leaves within days rather than weeks.[1]\n\nThe 14 mineral nutrients split into two groups by how much the plant uses. The six macronutrients, nitrogen, phosphorus, potassium, calcium, magnesium, and sulfur, are taken up in the largest amounts and build the bulk of the plant's tissue and machinery.[1][2] The eight micronutrients, iron, manganese, zinc, copper, boron, molybdenum, chlorine, and nickel, are needed only in trace amounts but are just as essential, since a shortage of any one stalls growth.[1][2] A complete hydroponic fertilizer already contains all of them in balance, so day-to-day management is less about choosing nutrients and more about keeping the water in the range where roots can absorb them.\n\nThat management runs on two independent measurements. pH governs chemistry: it decides which of the nutrients already in the water stay dissolved and available for uptake, and for most crops the working window sits between about 5.5 and 6.5.[3][8] Electrical conductivity (EC) governs strength: it reads the total concentration of dissolved salts, which tells you how rich the feed is overall but nothing about the ratio of one nutrient to another.[6][4] Parts per million (PPM) is a second way of expressing EC, and it carries a catch, because two meters can convert the same water into very different PPM readings.[7]","introHtml":"Hydroponic plants need 17 essential elements, the same set every plant uses, but three of them, carbon, hydrogen, and oxygen, come free from air and water, which leaves 14 mineral nutrients that you have to deliver in the solution.[1][2] In soil, clay and organic matter hold a reserve of those minerals and release them slowly, but a soilless system has no such buffer, which is why the makeup of the nutrient solution and steady monitoring matter more here, and why a problem can appear in the leaves within days rather than weeks.[1]
\nThe 14 mineral nutrients split into two groups by how much the plant uses. The six macronutrients, nitrogen, phosphorus, potassium, calcium, magnesium, and sulfur, are taken up in the largest amounts and build the bulk of the plant's tissue and machinery.[1][2] The eight micronutrients, iron, manganese, zinc, copper, boron, molybdenum, chlorine, and nickel, are needed only in trace amounts but are just as essential, since a shortage of any one stalls growth.[1][2] A complete hydroponic fertilizer already contains all of them in balance, so day-to-day management is less about choosing nutrients and more about keeping the water in the range where roots can absorb them.
\nThat management runs on two independent measurements. pH governs chemistry: it decides which of the nutrients already in the water stay dissolved and available for uptake, and for most crops the working window sits between about 5.5 and 6.5.[3][8] Electrical conductivity (EC) governs strength: it reads the total concentration of dissolved salts, which tells you how rich the feed is overall but nothing about the ratio of one nutrient to another.[6][4] Parts per million (PPM) is a second way of expressing EC, and it carries a catch, because two meters can convert the same water into very different PPM readings.[7]
\n","outroMarkdown":null,"outroHtml":null,"contentJson":{},"configJson":{},"noteMarkdown":null,"noteHtml":null,"sortOrder":0},{"id":"272ee0bf-aab0-4e1f-abf8-17f1b09e1c37","sectionKey":"essential_nutrients_table","sectionType":"table_section","heading":"What are the essential nutrients for hydroponic plants?","introMarkdown":"Plants draw 14 mineral nutrients from the solution, grouped into six macronutrients used in bulk and eight micronutrients used in trace amounts.[1][2] The table lists each element, its group, its role, and where a shortage tends to show up first.","introHtml":"Plants draw 14 mineral nutrients from the solution, grouped into six macronutrients used in bulk and eight micronutrients used in trace amounts.[1][2] The table lists each element, its group, its role, and where a shortage tends to show up first.
\n","outroMarkdown":"A complete hydroponic fertilizer supplies all 14 in balance, so you rarely dose them one at a time.[8] Knowing each role still matters, because the pattern of a deficiency, old leaves or new, points to which nutrient is short and whether the cause is the recipe or the pH.[1][2]","outroHtml":"A complete hydroponic fertilizer supplies all 14 in balance, so you rarely dose them one at a time.[8] Knowing each role still matters, because the pattern of a deficiency, old leaves or new, points to which nutrient is short and whether the cause is the recipe or the pH.[1][2]
\n","contentJson":{"rows":[{"cells":["Nitrogen (N)","Macronutrient","Amino acids and proteins; leafy growth [1]","Older leaves (mobile) [1]"]},{"cells":["Phosphorus (P)","Macronutrient","Energy transfer (ATP), membranes, DNA [1]","Older leaves (mobile) [1]"]},{"cells":["Potassium (K)","Macronutrient","Enzyme activation, turgor, water regulation [1]","Older leaves (mobile) [1]"]},{"cells":["Calcium (Ca)","Macronutrient","Cell wall structure; moves only with water flow [2]","New growth and fruit (tipburn, blossom-end rot) [2][6]"]},{"cells":["Magnesium (Mg)","Macronutrient","Center of the chlorophyll molecule [1][2]","Older to middle leaves (mobile) [2]"]},{"cells":["Sulfur (S)","Macronutrient","Amino acids and proteins [1]","Newer leaves [1]"]},{"cells":["Iron (Fe)","Micronutrient","Chlorophyll formation and photosynthesis [2]","New growth, worsened by high pH [2]"]},{"cells":["Manganese, zinc, copper (Mn, Zn, Cu)","Micronutrients","Enzyme activation and photosynthesis [1]","Varies; excess is the more common risk [1]"]},{"cells":["Boron (B)","Micronutrient","Cell walls, new tips and reproductive growth [1]","New growth (immobile) [1]"]},{"cells":["Molybdenum, chlorine, nickel (Mo, Cl, Ni)","Micronutrients","Nitrogen use, osmosis, enzyme function [1]","Varies by element [1]"]}],"columns":["Nutrient","Group","Main role in the plant","Where deficiency shows first"]},"configJson":{},"noteMarkdown":null,"noteHtml":null,"sortOrder":1},{"id":"06cd47a0-6483-4a0d-b8df-21f489b03940","sectionKey":"nutrient_functions","sectionType":"markdown_section","heading":"What do the essential nutrients do?","introMarkdown":"Each nutrient has a specific job, and the job tells you what a shortage will look like and where on the plant it shows up first.[1][2] The macronutrients build most of the plant's structure, while the micronutrients act mostly as helpers inside enzymes and in photosynthesis.[1]\n\n### Nitrogen, phosphorus, and potassium\n\nThese three drive the bulk of growth. Nitrogen is a building block of amino acids, proteins, and nucleic acids, so it powers leaf and stem development and is usually the first nutrient a fast-growing crop draws down.[1] Phosphorus sits at the center of energy transfer through ATP and forms part of cell membranes and DNA, which makes it central to rooting and flowering.[1] Potassium activates enzymes and regulates the turgor and water balance that keep cells firm and stomata working.[1] All three move freely within the plant, so a shortage pulls them from older leaves to feed new growth and the yellowing appears on the lower foliage first.[1]\n\n### Calcium and magnesium\n\nCalcium and magnesium cause outsized trouble when they are off. Calcium builds and stabilizes cell walls, and it travels only in the transpiration stream, so it cannot be moved back out of old tissue to rescue young growth.[2] That one fact explains tipburn in lettuce and blossom-end rot in tomato, where the solution is full of calcium yet the youngest tissue still goes short because water is not reaching it fast enough.[6][2] Magnesium is the atom at the center of every chlorophyll molecule, so a shortage reads as interveinal yellowing, and because it is mobile that yellowing starts on the older, lower leaves.[1][2]\n\n### Sulfur and the micronutrients\n\nSulfur is part of several amino acids and proteins, so it sits in the structural group even though plants use less of it, and in a complete recipe it rarely runs short.[1] Among the micronutrients, iron causes the most day-to-day trouble, because it drives chlorophyll formation and its availability collapses as pH rises; the tell is interveinal yellowing on the newest leaves, usually from a high pH locking the iron away rather than a missing dose.[2] Manganese, zinc, and copper work as enzyme activators in amounts measured in fractions of a part per million, where the practical risk is buildup and toxicity rather than shortage.[1] Boron supports cell walls and new growth, so like calcium its deficiency appears on the newest tissue, while molybdenum, chlorine, and nickel are needed in such small amounts that a standard mix covers them without separate attention.[1]","introHtml":"Each nutrient has a specific job, and the job tells you what a shortage will look like and where on the plant it shows up first.[1][2] The macronutrients build most of the plant's structure, while the micronutrients act mostly as helpers inside enzymes and in photosynthesis.[1]
\nThese three drive the bulk of growth. Nitrogen is a building block of amino acids, proteins, and nucleic acids, so it powers leaf and stem development and is usually the first nutrient a fast-growing crop draws down.[1] Phosphorus sits at the center of energy transfer through ATP and forms part of cell membranes and DNA, which makes it central to rooting and flowering.[1] Potassium activates enzymes and regulates the turgor and water balance that keep cells firm and stomata working.[1] All three move freely within the plant, so a shortage pulls them from older leaves to feed new growth and the yellowing appears on the lower foliage first.[1]
\nCalcium and magnesium cause outsized trouble when they are off. Calcium builds and stabilizes cell walls, and it travels only in the transpiration stream, so it cannot be moved back out of old tissue to rescue young growth.[2] That one fact explains tipburn in lettuce and blossom-end rot in tomato, where the solution is full of calcium yet the youngest tissue still goes short because water is not reaching it fast enough.[6][2] Magnesium is the atom at the center of every chlorophyll molecule, so a shortage reads as interveinal yellowing, and because it is mobile that yellowing starts on the older, lower leaves.[1][2]
\nSulfur is part of several amino acids and proteins, so it sits in the structural group even though plants use less of it, and in a complete recipe it rarely runs short.[1] Among the micronutrients, iron causes the most day-to-day trouble, because it drives chlorophyll formation and its availability collapses as pH rises; the tell is interveinal yellowing on the newest leaves, usually from a high pH locking the iron away rather than a missing dose.[2] Manganese, zinc, and copper work as enzyme activators in amounts measured in fractions of a part per million, where the practical risk is buildup and toxicity rather than shortage.[1] Boron supports cell walls and new growth, so like calcium its deficiency appears on the newest tissue, while molybdenum, chlorine, and nickel are needed in such small amounts that a standard mix covers them without separate attention.[1]
\n","outroMarkdown":null,"outroHtml":null,"contentJson":{},"configJson":{},"noteMarkdown":null,"noteHtml":null,"sortOrder":2},{"id":"401133b5-e456-43ec-821a-3bc07d820798","sectionKey":"manage_ph","sectionType":"markdown_section","heading":"How do you manage pH in a hydroponic system?","introMarkdown":"Keep the nutrient solution's pH between about 5.5 and 6.5, the band where the widest range of nutrients stays dissolved and available to roots.[3][8] pH does not feed the plant; it governs chemistry, deciding which of the nutrients already in the water the roots can take up, so outside the window elements drop out of solution or bind into forms the plant cannot use even while a lab test still shows them present.[6]\n\n### Why the range matters\n\nEach nutrient has its own availability curve across pH, and 5.5 to 6.5 is the overlap where most of them are reachable at once.[3] Nitrogen is most available from about 6.0 upward, while iron and the other metal micronutrients get harder to absorb as pH climbs, which is why a high pH shows first as iron-deficiency yellowing on new leaves.[1][2] Push below roughly 5.0 and the balance tips toward possible toxicities.[2] Some growers run a tighter target, such as 5.6 to 6.0, to favor phosphorus uptake.[5]\n\n### How to move pH and hold it\n\nYou raise or lower pH by adding a base or an acid to the reservoir, not by changing the fertilizer.[6] To bring pH down, growers add a food-safe acid such as phosphoric, nitric, or sulfuric a little at a time, since a large dose can drop the pH sharply and stress the roots; a potassium hydroxide base brings it back up.[5] pH also drifts on its own as plants feed and as the water warms, so check it often, calibrate the meter about once a week against pH 4 and pH 7 reference fluids, and correct in small steps.[8]","introHtml":"Keep the nutrient solution's pH between about 5.5 and 6.5, the band where the widest range of nutrients stays dissolved and available to roots.[3][8] pH does not feed the plant; it governs chemistry, deciding which of the nutrients already in the water the roots can take up, so outside the window elements drop out of solution or bind into forms the plant cannot use even while a lab test still shows them present.[6]
\nEach nutrient has its own availability curve across pH, and 5.5 to 6.5 is the overlap where most of them are reachable at once.[3] Nitrogen is most available from about 6.0 upward, while iron and the other metal micronutrients get harder to absorb as pH climbs, which is why a high pH shows first as iron-deficiency yellowing on new leaves.[1][2] Push below roughly 5.0 and the balance tips toward possible toxicities.[2] Some growers run a tighter target, such as 5.6 to 6.0, to favor phosphorus uptake.[5]
\nYou raise or lower pH by adding a base or an acid to the reservoir, not by changing the fertilizer.[6] To bring pH down, growers add a food-safe acid such as phosphoric, nitric, or sulfuric a little at a time, since a large dose can drop the pH sharply and stress the roots; a potassium hydroxide base brings it back up.[5] pH also drifts on its own as plants feed and as the water warms, so check it often, calibrate the meter about once a week against pH 4 and pH 7 reference fluids, and correct in small steps.[8]
\n","outroMarkdown":null,"outroHtml":null,"contentJson":{},"configJson":{},"noteMarkdown":null,"noteHtml":null,"sortOrder":3},{"id":"ff1a79c0-91e0-429f-99b1-68f2bb0525e1","sectionKey":"manage_ec_ppm","sectionType":"markdown_section","heading":"How do you manage EC and PPM?","introMarkdown":"Set electrical conductivity (EC) to match the crop and its growth stage, then hold it steady as the reservoir changes.[4][6] EC measures the total concentration of dissolved salts in the solution, which tells you how strong the feed is overall but nothing about the ratio of one nutrient to another, so treat it as a strength gauge, not a balance check.[6][4]\n\n### What EC to target\n\nFreshly mixed solutions usually land between about 1.5 and 3.5 dS/m, written interchangeably as mS/cm since the two units are numerically equal.[4] Start a young crop at the low end and raise the EC as it matures and its demand grows.[4] Leafy greens sit near the bottom of the band and fruiting crops near the top, since tomatoes handle higher salt levels than cucumbers, peppers, or lettuce.[4]\n\n### Managing EC drift\n\nEC does not stay put. As plants pull nutrients out of the water the EC falls, and as water evaporates or transpires away the salts concentrate and the EC rises.[6] The day-to-day fix is to top up with plain water when EC climbs and to add fertilizer concentrate when it drops.[6] In a media-based system, a useful check is the runoff: the leachate draining from the slab should stay within about 1.0 dS/m of the solution you applied, and a wider gap signals salts building up in the root zone.[4] Because small errors add up, most growers fully replace the reservoir every few weeks rather than topping up indefinitely.[9]","introHtml":"Set electrical conductivity (EC) to match the crop and its growth stage, then hold it steady as the reservoir changes.[4][6] EC measures the total concentration of dissolved salts in the solution, which tells you how strong the feed is overall but nothing about the ratio of one nutrient to another, so treat it as a strength gauge, not a balance check.[6][4]
\nFreshly mixed solutions usually land between about 1.5 and 3.5 dS/m, written interchangeably as mS/cm since the two units are numerically equal.[4] Start a young crop at the low end and raise the EC as it matures and its demand grows.[4] Leafy greens sit near the bottom of the band and fruiting crops near the top, since tomatoes handle higher salt levels than cucumbers, peppers, or lettuce.[4]
\nEC does not stay put. As plants pull nutrients out of the water the EC falls, and as water evaporates or transpires away the salts concentrate and the EC rises.[6] The day-to-day fix is to top up with plain water when EC climbs and to add fertilizer concentrate when it drops.[6] In a media-based system, a useful check is the runoff: the leachate draining from the slab should stay within about 1.0 dS/m of the solution you applied, and a wider gap signals salts building up in the root zone.[4] Because small errors add up, most growers fully replace the reservoir every few weeks rather than topping up indefinitely.[9]
\n","outroMarkdown":null,"outroHtml":null,"contentJson":{},"configJson":{},"noteMarkdown":null,"noteHtml":null,"sortOrder":4},{"id":"92239f4f-238b-42bb-b56e-061f50a1eadd","sectionKey":"crop_targets_table","sectionType":"table_section","heading":"What EC and pH should common crops target?","introMarkdown":"Target EC rises with a crop's appetite for salts and its stage of growth, while the pH window stays close to 5.5 to 6.5 across the board.[4][3] The ranges below are typical starting points for the recirculating solution.","introHtml":"Target EC rises with a crop's appetite for salts and its stage of growth, while the pH window stays close to 5.5 to 6.5 across the board.[4][3] The ranges below are typical starting points for the recirculating solution.
\n","outroMarkdown":"Treat these as opening settings, not fixed rules. A lettuce study found the best yields at an EC of about 1.8 mS/cm, with growth falling off at both lower and higher levels, and no yield penalty for holding pH from 6.0 to 6.2.[6]","outroHtml":"Treat these as opening settings, not fixed rules. A lettuce study found the best yields at an EC of about 1.8 mS/cm, with growth falling off at both lower and higher levels, and no yield penalty for holding pH from 6.0 to 6.2.[6]
\n","contentJson":{"rows":[{"cells":["Lettuce and leafy greens","1.2 to 1.8","5.6 to 6.2","Yield peaks near 1.8; ease EC down in summer heat to limit tipburn [6][5]"]},{"cells":["Basil and leafy herbs","1.0 to 1.6","5.5 to 6.0","Start low for seedlings, raise as they fill in [10]"]},{"cells":["Cucumber and pepper","about 2.0 to 2.5","5.5 to 6.5","Less salt-tolerant than tomato, so hold below the tomato range [4]"]},{"cells":["Tomato","2.0 to 3.5","5.5 to 6.5","Raise EC by stage; highest for mature fruiting plants [3][4]"]}],"columns":["Crop","Typical EC (mS/cm or dS/m)","Typical pH","Notes"]},"configJson":{},"noteMarkdown":null,"noteHtml":null,"sortOrder":5},{"id":"2ff7e280-f3c3-401e-bd0e-60f0c987e979","sectionKey":"ppm_scale_caveat","sectionType":"markdown_section","heading":"Why do two PPM readings disagree? The 500 and 700 scales","introMarkdown":"A PPM reading only means something once you know which conversion scale the meter used, because no meter measures parts per million directly.[7][6] Every TDS or PPM meter reads electrical conductivity and then multiplies it by a fixed factor to estimate the dissolved solids, and two common factors are in use.[7]\n\n### The 500 and 700 scales\n\nThe 500 scale, sometimes labeled NaCl or TDS, multiplies EC in mS/cm by 500, so an EC of 2.0 reads as 1000 PPM.[7] The 700 scale, sometimes labeled KCl or 442, multiplies the same EC by 700, so that identical solution reads as 1400 PPM.[7] Neither is measuring sodium chloride or potassium chloride specifically; each is just a different assumption baked into the same conductivity reading.[7] Bluelab's own example makes the gap concrete: a solution at 2.4 EC shows as 1200 PPM on the 500 scale and 1680 PPM on the 700 scale, a difference of 480 PPM for water that has not changed at all.[7]\n\n### How to avoid the trap\n\nMatch the scale on your meter to the scale in whatever recipe or chart you follow, or the numbers will not line up.[7] The cleaner habit is to work in EC directly, in mS/cm or the numerically identical dS/m, which removes the ambiguity because EC is the actual measurement rather than a converted estimate.[7][4] When a grower quotes a bare PPM target with no scale attached, convert it back to EC before comparing it against your own system.[7]","introHtml":"A PPM reading only means something once you know which conversion scale the meter used, because no meter measures parts per million directly.[7][6] Every TDS or PPM meter reads electrical conductivity and then multiplies it by a fixed factor to estimate the dissolved solids, and two common factors are in use.[7]
\nThe 500 scale, sometimes labeled NaCl or TDS, multiplies EC in mS/cm by 500, so an EC of 2.0 reads as 1000 PPM.[7] The 700 scale, sometimes labeled KCl or 442, multiplies the same EC by 700, so that identical solution reads as 1400 PPM.[7] Neither is measuring sodium chloride or potassium chloride specifically; each is just a different assumption baked into the same conductivity reading.[7] Bluelab's own example makes the gap concrete: a solution at 2.4 EC shows as 1200 PPM on the 500 scale and 1680 PPM on the 700 scale, a difference of 480 PPM for water that has not changed at all.[7]
\nMatch the scale on your meter to the scale in whatever recipe or chart you follow, or the numbers will not line up.[7] The cleaner habit is to work in EC directly, in mS/cm or the numerically identical dS/m, which removes the ambiguity because EC is the actual measurement rather than a converted estimate.[7][4] When a grower quotes a bare PPM target with no scale attached, convert it back to EC before comparing it against your own system.[7]
\n","outroMarkdown":null,"outroHtml":null,"contentJson":{},"configJson":{},"noteMarkdown":null,"noteHtml":null,"sortOrder":6},{"id":"409dcac4-8dde-4836-a6bb-9ababb300f28","sectionKey":"trade_offs","sectionType":"markdown_section","heading":"Trade-offs and what to watch","introMarkdown":"The hardest part of hydroponic nutrition is what the meters do not tell you, so a few limits are worth holding in mind alongside the target numbers.\n\n### EC hides the balance\n\nEC reports total salts, which means a solution can read exactly on target while a single nutrient is depleted or oversupplied.[6][4] If plants show a deficiency the meters call normal, the answer is usually a fresh reservoir or a lab test of the solution, not another dose against the same EC number, and the position of the symptom is the clue: old lower leaves point to a mobile nutrient like nitrogen or magnesium, while the newest leaves point to an immobile one like calcium, iron, or boron.[1][2] Working from a complete, balanced fertilizer keeps the ratios sensible between those checks.[4]\n\n### Tipburn is a water problem, not only a feeding problem\n\nLettuce tipburn is a calcium shortage in the youngest leaves, but it often happens when calcium is plentiful in the solution, because heat and high humidity slow transpiration and calcium moves only with water flow.[6] Trials found that increasing airflow with vertical fans, or easing the EC down in hot weather, controlled tipburn better than adding more calcium to the recipe.[6]\n\n### Source water and local conditions\n\nTest the water you begin with, since calcium, magnesium, iron, and manganese already in the supply count toward your totals; useful ceilings are roughly 150 ppm calcium, 75 ppm magnesium, and 1 ppm each of iron and manganese.[8] Climate matters too, so warm-region growers are advised to run more dilute solutions and irrigate more often than the stronger recipes written for cooler northern greenhouses.[4]","introHtml":"The hardest part of hydroponic nutrition is what the meters do not tell you, so a few limits are worth holding in mind alongside the target numbers.
\nEC reports total salts, which means a solution can read exactly on target while a single nutrient is depleted or oversupplied.[6][4] If plants show a deficiency the meters call normal, the answer is usually a fresh reservoir or a lab test of the solution, not another dose against the same EC number, and the position of the symptom is the clue: old lower leaves point to a mobile nutrient like nitrogen or magnesium, while the newest leaves point to an immobile one like calcium, iron, or boron.[1][2] Working from a complete, balanced fertilizer keeps the ratios sensible between those checks.[4]
\nLettuce tipburn is a calcium shortage in the youngest leaves, but it often happens when calcium is plentiful in the solution, because heat and high humidity slow transpiration and calcium moves only with water flow.[6] Trials found that increasing airflow with vertical fans, or easing the EC down in hot weather, controlled tipburn better than adding more calcium to the recipe.[6]
\nTest the water you begin with, since calcium, magnesium, iron, and manganese already in the supply count toward your totals; useful ceilings are roughly 150 ppm calcium, 75 ppm magnesium, and 1 ppm each of iron and manganese.[8] Climate matters too, so warm-region growers are advised to run more dilute solutions and irrigate more often than the stronger recipes written for cooler northern greenhouses.[4]
\n","outroMarkdown":null,"outroHtml":null,"contentJson":{},"configJson":{},"noteMarkdown":null,"noteHtml":null,"sortOrder":7},{"id":"d30d8b21-4836-4375-b7fc-94d22120c904","sectionKey":"contributor_perspective","sectionType":"markdown_section","heading":"How this answer was researched","introMarkdown":"The nutrient roles, pH ranges, and EC targets here were drawn from university extension and horticulture-science sources, including Penn State Extension, the Ohio State University, the University of Florida IFAS, the University of Missouri Extension, and a peer-reviewed lettuce study from the USDA Agricultural Research Service, then cross-checked against each other on the date shown.[1][3][4][6][8] Where a specific figure is quoted, such as the EC of a freshly mixed solution or the factors behind the 500 and 700 PPM scales, it is tied to the source that states it rather than to a rule of thumb.[4][7] Crop targets vary with cultivar, season, water source, and system type, so the ranges are starting points to calibrate against your own plants and runoff readings, not fixed prescriptions. Growers, greenhouse managers, and horticulturists who dial in these numbers day to day are encouraged to contribute field notes so the answer stays accurate for the next reader.","introHtml":"The nutrient roles, pH ranges, and EC targets here were drawn from university extension and horticulture-science sources, including Penn State Extension, the Ohio State University, the University of Florida IFAS, the University of Missouri Extension, and a peer-reviewed lettuce study from the USDA Agricultural Research Service, then cross-checked against each other on the date shown.[1][3][4][6][8] Where a specific figure is quoted, such as the EC of a freshly mixed solution or the factors behind the 500 and 700 PPM scales, it is tied to the source that states it rather than to a rule of thumb.[4][7] Crop targets vary with cultivar, season, water source, and system type, so the ranges are starting points to calibrate against your own plants and runoff readings, not fixed prescriptions. Growers, greenhouse managers, and horticulturists who dial in these numbers day to day are encouraged to contribute field notes so the answer stays accurate for the next reader.
\n","outroMarkdown":null,"outroHtml":null,"contentJson":{},"configJson":{},"noteMarkdown":"This answer was written and reviewed by the AnswerStack Editorial Team, which has no commercial stake in the products, companies, or methods discussed. Every claim is cited inline and verified on the dates shown.","noteHtml":"This answer was written and reviewed by the AnswerStack Editorial Team, which has no commercial stake in the products, companies, or methods discussed. Every claim is cited inline and verified on the dates shown.
\n","sortOrder":8}],"citations":[{"title":"Hydroponics Systems and Principles of Plant Nutrition: Essential Nutrients, Function, Deficiency, and Excess","url":"https://extension.psu.edu/hydroponics-systems-and-principles-of-plant-nutrition-essential-nutrients-function-deficiency-and-excess","excerpt":"Carbon, hydrogen, and oxygen from air and water. The rest of the nutrients are from soil or in the case of hydroponics from nutrient solutions or aggregate media.","quoteText":null,"sourceRole":"PRIMARY","verifiedAt":"2026-07-18T00:00:00","supportsText":"Plants need 17 essential nutrients; carbon, hydrogen, and oxygen come from air and water while the rest come from the nutrient solution; macronutrient and micronutrient lists and functions; nutrient mobility and where deficiencies appear; optimal hydroponic pH range 5.0 to 7.0; EC monitoring","domain":"extension.psu.edu","publisherName":"Penn State Extension"},{"title":"Understanding Essential Nutrients in Hydroponic Production","url":"https://gpnmag.com/article/hydroponic-systems-principles-of-plant-nutrition/","excerpt":"In general, the optimal pH range for growing vegetables hydroponically is 5.0 to 7.0.","quoteText":null,"sourceRole":"INDEPENDENT","verifiedAt":"2026-07-18T00:00:00","supportsText":"17 essential nutrients; magnesium is the center of the chlorophyll molecule; calcium is transported in water-conducting tissue and its deficiency (tipburn) shows on new growth; iron deficiency shows on new growth and its most common cause is high pH; optimal pH range 5.0 to 7.0","domain":"gpnmag.com","publisherName":"Greenhouse Product News"},{"title":"Hydroponic Nutrient Solution for Optimized Greenhouse Tomato Production","url":"https://cfaes.osu.edu/fact-sheet/hydroponic-nutrient-solution-optimized-greenhouse-tomato-production","excerpt":"For hydroponic nutrient solutions, the range of pH where most nutrients are highly available is 5.5 to 6.5.","quoteText":null,"sourceRole":"PRIMARY","verifiedAt":"2026-07-18T00:00:00","supportsText":"Greenhouse tomato solution EC about 2.0 dS/m at stage 1 rising to about 2.4 dS/m at stage 3; the pH range where most nutrients are highly available for hydroponic solutions is 5.5 to 6.5; staged nutrient concentrations","domain":"cfaes.osu.edu","publisherName":"Ohio State University CFAES"},{"title":"Water and Nutrient Management Guidelines for Greenhouse Hydroponic Vegetable Production in Florida","url":"https://ask.ifas.ufl.edu/publication/HS1274","excerpt":"the final EC is usually in the range of 1.5 to 3.5 (dS m-1).","quoteText":null,"sourceRole":"PRIMARY","verifiedAt":"2026-07-18T00:00:00","supportsText":"Made-up nutrient solution EC is usually in the range of 1.5 to 3.5 dS/m, starting low for a young crop and increased as it matures; leachate EC should stay within 1.0 dS/m of the applied solution; tomatoes tolerate higher salt than cucumbers, peppers, or lettuce; Florida growers should use more dilu","domain":"ask.ifas.ufl.edu","publisherName":"University of Florida IFAS Extension"},{"title":"Fertilizer Management for Greenhouse Vegetables","url":"https://ask.ifas.ufl.edu/publication/CV265","excerpt":"Maintain hydroponic solution pH at 5.6 to 6.0 to favor P uptake. Acidification can be accomplished by use of several acids such as sulfuric, nitric, or phosphoric.","quoteText":null,"sourceRole":"PRIMARY","verifiedAt":"2026-07-18T00:00:00","supportsText":"Maintain hydroponic solution pH at 5.6 to 6.0 to favor phosphorus uptake; acidification is accomplished with acids such as sulfuric, nitric, or phosphoric; accurate EC and pH records are important for fertilizer management","domain":"ask.ifas.ufl.edu","publisherName":"University of Florida IFAS Extension"},{"title":"Effects of Electrical Conductivity, pH, and Foliar Application of Calcium Chloride on Yield and Tipburn of Lactuca sativa Grown Using the Nutrient-Film Technique","url":"https://www.ars.usda.gov/ARSUserFiles/50820500/GPRG/2020PublicationsandSummaries/2020_Effects%20of%20Electrical%20Conductivity,%20pH,%20and%20Foliar%20Application%20of%20Calcium%20Chloride%20on%20Yield%20and%20Tipburn%20of%20Lactuca%20sativa%20Grown%20Using%20the%20Nutrient%E2%80%93Film%20Technique.pdf","excerpt":"EC indicates the total ion concentration in the solution and not individual nutrients.","quoteText":null,"sourceRole":"PRIMARY","verifiedAt":"2026-07-18T00:00:00","supportsText":"Lettuce maximum yields at or above 1.8 mS/cm, with yield reduction at low (0.8 to 1.2) and high (2.4) EC; maximum yield at pH 6.0 and 6.2; tipburn is caused by inadequate calcium to young leaves because calcium cannot be mobilized from older tissue via phloem; vertical airflow fans and lower EC cont","domain":"ars.usda.gov","publisherName":"HortScience (USDA Agricultural Research Service)"},{"title":"What are the different conductivity scales? What do they mean?","url":"https://support.bluelab.com/hc/en-us/articles/205237090-what-are-the-different-conductivity-scales-what-do-they-mean-","excerpt":"ppm500 = EC x 500 ... ppm700 = EC x 700. It is very important to match the scale on your meter to the scale being referred to in the book.","quoteText":null,"sourceRole":"SUPPORTING","verifiedAt":"2026-07-18T00:00:00","supportsText":"PPM is not measured directly; ppm500 = EC x 500 and ppm700 = EC x 700; a 2.4 EC solution reads 1200 ppm on the 500 scale and 1680 ppm on the 700 scale; match the scale on your meter to the scale referenced in a recipe","domain":"support.bluelab.com","publisherName":"Bluelab"},{"title":"Hydroponic Nutrient Solutions","url":"https://extension.missouri.edu/publications/g6984","excerpt":"the optimum pH for most hydroponic crops (with exceptions) is from 5.5 to 6.5","quoteText":null,"sourceRole":"PRIMARY","verifiedAt":"2026-07-18T00:00:00","supportsText":"The optimum pH for most hydroponic crops is 5.5 to 6.5; calibrate the meter once a week at pH 4 and pH 7; source water quality limits of calcium under 150 ppm, magnesium under 75 ppm, and iron and manganese under 1 ppm; nutrients must be constantly measured and adjusted","domain":"extension.missouri.edu","publisherName":"University of Missouri Extension"},{"title":"Hydroponic Gardening for the Homeowner and Small Grower","url":"https://fieldreport.caes.uga.edu/publications/C1315/","excerpt":"completely change out the water in a hydroponic garden every 3-4 weeks","quoteText":null,"sourceRole":"PRIMARY","verifiedAt":"2026-07-18T00:00:00","supportsText":"Completely change out the water in a hydroponic garden every 3 to 4 weeks; supply additional fertility every 1 to 2 weeks; hydroponic plants grow best at an air temperature of 65 to 75 F","domain":"fieldreport.caes.uga.edu","publisherName":"University of Georgia Extension"},{"title":"How to grow hydroponic basil: EC, pH, and light","url":"https://urbanharvestlab.com/blog/hydroponics/hydroponic-basil-ec-ph-light/","excerpt":"EC Range: 1.0 to 1.6 mS/cm. pH Range: 5.5 to 6.5. 5.5 to 6.0 is the sweet spot.","quoteText":null,"sourceRole":"SUPPORTING","verifiedAt":"2026-07-18T00:00:00","supportsText":"Hydroponic basil targets an EC of 1.0 to 1.6 mS/cm and a pH of 5.5 to 6.5, with 5.5 to 6.0 the ideal, starting at the low end of the EC range for young plants","domain":"urbanharvestlab.com","publisherName":"Urban Harvest Lab"}],"revisions":[],"relatedAnswers":[{"id":"693f10ff-745f-43f8-b1fe-acd9c83a5de9","slug":"what-is-hydroponics-and-how-does-it-work","question":"What is hydroponics and how does it work?","publishedAt":"2026-07-24T14:26:11.558","confidenceScore":90,"confidenceLabel":"High","industry":{"id":"13f844a6-82e8-4b4e-9a66-5dd1063cfaaa","slug":"agriculture","label":"Agriculture","description":"AgTech, crop science, and precision farming"},"topic":{"slug":"soilless-controlled-environment-growing","label":"Soilless & Controlled-Environment Growing","description":"Hydroponic, aeroponic, aquaponic, and vertical farming systems.","schemaKind":null},"contributor":{"id":"ec39deab-44fe-48d8-9029-fefe993ab85a","slug":"answer-stack","displayName":"AnswerStack","websiteUrl":null},"snippet":"Hydroponics grows plants without soil by feeding their roots a water-based nutrient solution, either directly or through an inert medium such as coconut coir or perlite. The grower supplies the water, dissolved oxygen, minerals, light, and controlled pH and nutrient strength that soil would normally handle. Common designs include wick, deep water culture, nutrient film technique, ebb and flow, drip, and aeroponic systems. Because the solution recirculates, hydroponics can cut water use sharply and raise yields in a smaller footprint.","url":"/q/what-is-hydroponics-and-how-does-it-work"},{"id":"f524cd18-e80d-49d6-a310-e4291c633980","slug":"what-are-the-easiest-plants-and-vegetables-to-grow-hydroponically","question":"What are the easiest plants and vegetables to grow hydroponically?","publishedAt":"2026-07-23T15:59:31.328","confidenceScore":90,"confidenceLabel":"High","industry":{"id":"13f844a6-82e8-4b4e-9a66-5dd1063cfaaa","slug":"agriculture","label":"Agriculture","description":"AgTech, crop science, and precision farming"},"topic":{"slug":"soilless-controlled-environment-growing","label":"Soilless & Controlled-Environment Growing","description":"Hydroponic, aeroponic, aquaponic, and vertical farming systems.","schemaKind":null},"contributor":{"id":"ec39deab-44fe-48d8-9029-fefe993ab85a","slug":"answer-stack","displayName":"AnswerStack","websiteUrl":null},"snippet":"Leafy greens and herbs are the most beginner-friendly hydroponic crops because they grow fast, need modest light and nutrients, and forgive small pH and EC swings. Lettuce and basil are the two standouts, both ready to harvest in weeks, with kale, mustard greens, chard, and mint close behind. Fruiting crops such as tomatoes, cucumbers, peppers, and strawberries are grown hydroponically too, but they run longer, demand higher nutrient levels, and usually need a media system, support, and more light.","url":"/q/what-are-the-easiest-plants-and-vegetables-to-grow-hydroponically"},{"id":"564c272e-fee1-4768-9332-4ad48911760f","slug":"which-hydroponic-system-type-should-a-beginner-start-with-dwc-nft-kratky-ebb-and-flow","question":"Which hydroponic system type should a beginner start with (DWC, NFT, Kratky, ebb and flow)?","publishedAt":"2026-07-23T15:59:22.977","confidenceScore":88,"confidenceLabel":"High","industry":{"id":"13f844a6-82e8-4b4e-9a66-5dd1063cfaaa","slug":"agriculture","label":"Agriculture","description":"AgTech, crop science, and precision farming"},"topic":{"slug":"soilless-controlled-environment-growing","label":"Soilless & Controlled-Environment Growing","description":"Hydroponic, aeroponic, aquaponic, and vertical farming systems.","schemaKind":null},"contributor":{"id":"ec39deab-44fe-48d8-9029-fefe993ab85a","slug":"answer-stack","displayName":"AnswerStack","websiteUrl":null},"snippet":"Beginners get the best results from the two systems with the fewest moving parts. The Kratky method is fully passive and needs no pump or electricity, while deep water culture runs a single air pump and is widely called the cheapest, easiest system to maintain. Nutrient film technique and ebb and flow work well but add pumps, timers, and tuning, and NFT can lose a crop within hours if flow stops. There is no single best system; the right first pick depends on your crop, budget, and attention.","url":"/q/which-hydroponic-system-type-should-a-beginner-start-with-dwc-nft-kratky-ebb-and-flow"},{"id":"c61993de-e4d9-4830-b271-d534d42589c5","slug":"whats-the-difference-between-hydroponics-aeroponics-and-aquaponics-and-which-suits-what","question":"What's the difference between hydroponics, aeroponics, and aquaponics, and which suits what?","publishedAt":"2026-07-23T15:59:19.214","confidenceScore":88,"confidenceLabel":"High","industry":{"id":"13f844a6-82e8-4b4e-9a66-5dd1063cfaaa","slug":"agriculture","label":"Agriculture","description":"AgTech, crop science, and precision farming"},"topic":{"slug":"soilless-controlled-environment-growing","label":"Soilless & Controlled-Environment Growing","description":"Hydroponic, aeroponic, aquaponic, and vertical farming systems.","schemaKind":null},"contributor":{"id":"ec39deab-44fe-48d8-9029-fefe993ab85a","slug":"answer-stack","displayName":"AnswerStack","websiteUrl":null},"snippet":"The three methods are all soilless but differ in how roots are fed and where nutrients come from. Hydroponics bathes roots in a grower-mixed nutrient solution and is the most established, suiting leafy greens through fruiting vegetables. Aeroponics mists roots in air, saving water and speeding propagation, but depends on constant power and misting. Aquaponics pairs fish and plants in a recirculating loop where bacteria turn fish waste into plant nutrients, best for greens grown alongside a hardy fish like tilapia.","url":"/q/whats-the-difference-between-hydroponics-aeroponics-and-aquaponics-and-which-suits-what"}],"contributorStats":{"verifiedAnswers":224,"openDisputes":0},"schemaJson":{"@context":"https://schema.org","@type":"Question","name":"What nutrients do hydroponic plants need, and how do I manage pH and EC/PPM?","text":"What nutrients do hydroponic plants need, and how do I manage pH and EC/PPM?","url":"https://www.answerstack.io/q/what-nutrients-do-hydroponic-plants-need-and-how-do-i-manage-ph-and-ec-ppm","answerCount":1,"datePublished":"2026-07-23T15:59:27.21","author":{"@type":"Person","name":"AnswerStack Editorial Team","worksFor":{"@type":"Organization","name":"AnswerStack"},"url":"https://www.answerstack.io/contributors/answer-stack"},"about":[{"@type":"Thing","name":"Soilless & Controlled-Environment Growing"},{"@type":"Thing","name":"Agriculture"}],"acceptedAnswer":{"@type":"Answer","text":"Hydroponic plants need the same 17 essential elements as soil-grown plants, and because there is no soil to buffer or resupply them, all 14 mineral nutrients have to be dissolved in the water you feed.[1][2] Six are macronutrients used in larger amounts, nitrogen, phosphorus, potassium, calcium, magnesium, and sulfur, and eight are micronutrients needed in trace amounts, iron, manganese, zinc, copper, boron, molybdenum, chlorine, and nickel.[1][2] You manage the solution with two separate dials: pH, held for most crops between about 5.5 and 6.5 so those nutrients stay chemically available, and electrical conductivity (EC), which reads total dissolved salts and tells you the overall strength of the feed rather than the balance of any single nutrient.[3][8][6] Freshly mixed solutions usually run an EC of roughly 1.5 to 3.5 dS/m, started low for young plants and raised as they mature, with leafy greens near the bottom of that band and fruiting crops like tomato at the top.[4][6][3] Parts per million (PPM) is just EC converted by a fixed factor, so a reading only means something once you know whether the meter uses the 500 or the 700 scale.[7]","url":"https://www.answerstack.io/q/what-nutrients-do-hydroponic-plants-need-and-how-do-i-manage-ph-and-ec-ppm","upvoteCount":0,"datePublished":"2026-07-23T15:59:27.21","dateModified":"2026-07-18T00:00:00","author":{"@type":"Person","name":"AnswerStack Editorial Team","worksFor":{"@type":"Organization","name":"AnswerStack"},"url":"https://www.answerstack.io/contributors/answer-stack"},"citation":[{"@type":"CreativeWork","name":"Hydroponics Systems and Principles of Plant Nutrition: Essential Nutrients, Function, Deficiency, and Excess","url":"https://extension.psu.edu/hydroponics-systems-and-principles-of-plant-nutrition-essential-nutrients-function-deficiency-and-excess"},{"@type":"CreativeWork","name":"Understanding Essential Nutrients in Hydroponic Production","url":"https://gpnmag.com/article/hydroponic-systems-principles-of-plant-nutrition/"},{"@type":"CreativeWork","name":"Hydroponic Nutrient Solution for Optimized Greenhouse Tomato Production","url":"https://cfaes.osu.edu/fact-sheet/hydroponic-nutrient-solution-optimized-greenhouse-tomato-production"},{"@type":"CreativeWork","name":"Water and Nutrient Management Guidelines for Greenhouse Hydroponic Vegetable Production in Florida","url":"https://ask.ifas.ufl.edu/publication/HS1274"},{"@type":"CreativeWork","name":"Fertilizer Management for Greenhouse Vegetables","url":"https://ask.ifas.ufl.edu/publication/CV265"},{"@type":"CreativeWork","name":"Effects of Electrical Conductivity, pH, and Foliar Application of Calcium Chloride on Yield and Tipburn of Lactuca sativa Grown Using the Nutrient-Film Technique","url":"https://www.ars.usda.gov/ARSUserFiles/50820500/GPRG/2020PublicationsandSummaries/2020_Effects%20of%20Electrical%20Conductivity,%20pH,%20and%20Foliar%20Application%20of%20Calcium%20Chloride%20on%20Yield%20and%20Tipburn%20of%20Lactuca%20sativa%20Grown%20Using%20the%20Nutrient%E2%80%93Film%20Technique.pdf"},{"@type":"CreativeWork","name":"What are the different conductivity scales? 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