Strawberry Fertilizer 8-12-32 | Chelated Micronutrients | Hydroponics, Soil & Foliar Application
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Water-soluble fertilizer for strawberries and other berries · 8-12-32 · chelated micronutrients · CDFA registered
About Strawberry Fertilizer 8-12-32
Strawberry Fertilizer 8-12-32 is a water-soluble fertilizer for strawberries, raspberries, blackberries, and the other berries and fruit trees named on its label. It supplies 32% soluble potash (K₂O), 12% available phosphate (P₂O₅), and 8% nitrogen, 90% of it nitrate, with EDTA-chelated iron, manganese, zinc, and copper plus boron and molybdenum. The label rate for berries is 3 grams per plant every 4 to 6 weeks, from planting until just before the first harvest. With a soil test you can size a bed by the potash the test calls for, and in hydroponics you dose it to a potassium target.
It is a potash-rich supplement, not a complete program. It contains no calcium or magnesium. Its nitrogen is mostly nitrate, which university guidance advises against for blueberries and cranberries, and university guides feed established June-bearing strawberry beds after harvest rather than in spring. Keep its concentrate separate from calcium concentrates.
- 32% K₂O Each pound supplies 145 g of potash, 54 g of available phosphate, and 36 g of nitrogen
- 3 g per plant The label’s berry rate, every 4 to 6 weeks. A 1 lb bag holds about 150 of these doses
- No Ca or Mg Supply calcium and magnesium separately. See companion products
Product facts & composition
| Specification | Detail |
|---|---|
| Total nitrogen (N) | 8.00%: 7.20% nitrate nitrogen, 0.80% ammoniacal nitrogen |
| Available phosphate (P₂O₅) | 12.00% |
| Soluble potash (K₂O) | 32.00% |
| Iron (Fe) | 0.50%, all chelated |
| Zinc (Zn) | 0.30%, all chelated |
| Manganese (Mn) | 0.20%, all chelated |
| Boron (B) | 0.10% |
| Copper (Cu) | 0.05%, all chelated |
| Molybdenum (Mo) | 0.001% |
| Calcium, magnesium | None guaranteed |
| Derived from | Monopotassium phosphate, potassium nitrate, ammonium sulfate, iron EDTA, boric acid, manganese EDTA, copper EDTA, zinc EDTA, sodium molybdate |
| Form | White to off-white powder or fine granules. The Safety Data Sheet describes it as highly water-soluble and fully soluble at recommended use rates |
| In solution | 1 g of product per liter adds 80 ppm nitrogen (72 nitrate N, 8 ammoniacal N), 52 ppm phosphorus, 266 ppm potassium, 5 ppm iron, 3 ppm zinc, 2 ppm manganese, 1 ppm boron, 0.5 ppm copper, and 0.01 ppm molybdenum. 1 g per US gallon adds 21 ppm N, 14 ppm P, and 70 ppm K |
| Registration | Registered with the California Department of Food and Agriculture (CDFA); CDFA-approved label dated March 25, 2025 |
| Heavy-metal test | Tested by an independent laboratory (AgroLab/Matrix Sciences; sample received December 16, 2024; reviewed December 20, 2024): arsenic 0.34, cadmium 0.04, cobalt 0.28, lead 0.65, nickel 0.79, selenium 3.03 mg/kg, mercury not detected. Arsenic, cadmium, and lead in the tested sample were well below California’s limits for fertilizers. See Product documents |
| Hazards | Harmful if swallowed. Avoid contact with eyes, open cuts, or sores, and avoid breathing dust. Contains potassium nitrate. See Handling, storage & limitations |
| Package sizes | 1, 2, 5, 10, and 25 lb |
Percentages are by weight. One pound supplies 145 g (0.32 lb) of potash (K₂O), 54 g (0.12 lb) of available phosphate (P₂O₅), and 36 g (0.08 lb) of nitrogen, 90% of it nitrate. Labels state phosphorus and potassium as oxides; the solution figures convert them to elements (P = P₂O₅ × 0.436, K = K₂O × 0.830), because hydroponic recipes use elemental ppm. The ammonium sulfate also supplies a little sulfur, which the label does not guarantee. Weigh the product: this page assumes no weight for a spoonful.
Best uses & benefits
Choose it when berries or fruit trees need potash and some phosphate, and you have another source of nitrogen, calcium, and magnesium.
Strawberries in garden beds
The label’s rate, 3 g per plant every 4 to 6 weeks from planting until just before the first harvest, fits a new planting. The label gives no schedule for established beds; for June-bearers, Oregon State and Iowa State Extension feed after the last harvest, at renovation, rather than in spring, and a soil test sizes that feeding. The CDFA and UC Davis guidelines estimate that a 30-ton-per-acre strawberry crop removes about 170 lb of potash (K₂O) per acre in its fruit.
Raspberries and blackberries
Both are on the label at 3 g per plant. Oregon State Extension says the main nutrient blackberries need after planting is nitrogen, and its raspberry guide gives nitrogen rates only, so use this product on brambles where a soil test shows potassium or phosphorus is low, and plan nitrogen separately.
The fruit trees on its label
The label gives per-tree rates for cherries, apples, pears, peaches, and plums. Penn State Extension notes that a mature apple tree usually needs only nitrogen, so use it on trees where a soil or leaf test shows potassium is low. It is not a nitrogen source for trees. See the tree rates.
Hydroponic strawberry solutions
Dosed to the 117 ppm potassium of the Yamazaki strawberry solution, it supplies about as much phosphorus as that solution calls for, with calcium nitrate in a separate stock for calcium and the rest of the nitrogen, and magnesium sulfate for magnesium. See the hydroponic formula.
Where it is a poor fit
- Blueberries and cranberries as the main fertilizer. 90% of its nitrogen is nitrate; see the blueberry and cranberry note under Application rates.
- Spring feeding of established June-bearing beds. Oregon State Extension says spring fertilizing of established plantings increases leaf growth but does not result in more or larger berries, and Iowa State that it produces softer fruit and more disease.
- Soils that test high in potassium. University of Florida IFAS recommends no potash for strawberries on soils testing high, and the Mid-Atlantic recommendations none on soils testing very high. The CDFA and UC Davis guidelines say little or no potash is needed when an ammonium acetate soil test is above 200 ppm.
- Soils already high in phosphorus. Every pound of potash from this product brings 0.375 lb of phosphate. For potash alone, Potassium Sulfate 0-0-53 adds none.
- Calcium or magnesium. It contains neither. Use Calcium Nitrate, Gypsum, Cal-Mag Plus, or Epsom Salt as your soil or water test calls for.
- Crops not on the label, and forage. Boron can injure crops the label does not list, and molybdenum can build up in forage to levels toxic to cattle, sheep, and goats.
- Foliar feeding and containers. This page gives no rate for either; see Application rates.
Application rates & directions
Use one of four bases: the label’s per-plant rate for berries, the label’s per-tree rate, a soil test’s potash recommendation for a bed or field, or a potassium target for a nutrient solution. Weigh the product. If the directions printed on your package differ from this page, contact us before applying.
Test first. The Mid-Atlantic recommendations and Clemson Extension put strawberries at soil pH 6.0 to 6.5, and Oregon State Extension puts blueberries at 4.5 to 5.5. A soil test is the guide to how much potash and phosphate a planting needs. For nutrient solutions, test your water for potassium, calcium, and magnesium before you mix.
Berries, per plant: the label rate
| Plants | Product per application | Supplies per application | How often |
|---|---|---|---|
| 1 plant | 3 g | 0.96 g potash (K₂O), 0.36 g phosphate (P₂O₅), 0.24 g nitrogen | Every 4 to 6 weeks |
| 10 plants | 30 g | 9.6 g K₂O, 3.6 g P₂O₅, 2.4 g N | Every 4 to 6 weeks |
| 25 plants | 75 g | 24 g K₂O, 9 g P₂O₅, 6 g N | Every 4 to 6 weeks |
The label starts the first application at planting and times the last one just before the first harvest. It gives the amount as “3 grams (approximately 1/2 teaspoon)” per plant. This page uses the weight, because the weight of a teaspoon of this product has not been measured; a kitchen scale that reads to 0.1 g is enough.
| Planting | University guidance | With this product |
|---|---|---|
| New planting, any type | Oregon State Extension splits first-year feeding into three applications, from 1 to 2 weeks after planting to about 2 months after | Follow the label: at planting, then every 4 to 6 weeks until just before the first harvest. For June-bearers planted in spring, whose first harvest is the next year, Oregon State stops about 2 months after planting; email us before feeding later |
| Established June-bearing bed | Oregon State: “Do not fertilize your June-bearing strawberries in the spring, unless your planting is not thriving.” Iowa State feeds them during renovation, immediately after the last harvest | The label gives no schedule for established beds. To follow this guidance, skip spring feedings and size the after-harvest feeding by a soil test (see beds and fields below) |
| Day-neutral and everbearing | Oregon State feeds them once a month for three months after spring growth begins, with an optional feeding in August | The label schedule stops just before the first harvest; email us before feeding plants that keep fruiting after that |
At close spacing the per-plant rate adds up. The Southern Regional Strawberry Plasticulture Production Guide (NC State) lists 17,500 plants per acre at 12-inch spacing in double rows on beds 5 feet apart. At that density each application is about 116 lb of product per acre (37 lb of potash), and four applications supply about 148 lb of potash per acre, close to the Mid-Atlantic and UF/IFAS recommendations for soil testing low in potassium (165 and 150 lb). On soil that tests medium or high, size the bed by a soil test instead. The label gives no rate for plants in containers of potting mix; email us before using it there.
Blueberries and cranberries. They are on the label, but 90% of this product’s nitrogen is nitrate. Oregon State Extension says blueberry plants cannot take up or use nitrate nitrogen and University of Florida IFAS that blueberries prefer ammonium; UMass Extension says cranberries preferentially use ammonium nitrogen. Use this product on them only where a soil or leaf test shows potassium or phosphorus is low, and supply nitrogen as ammonium sulfate.
Placement. The Mid-Atlantic recommendations call strawberries very salt-sensitive, and Oregon State Extension says blueberries are very sensitive to high salts. Spread the dose on the soil around the plant, never on the crown or leaves, and water it in. Oregon State advises removing any granules left on strawberry leaves and crowns, and not piling fertilizer against blueberry crowns.
Fruit trees: the label rate
| Trees | Product per tree, per application | Supplies per tree | How often |
|---|---|---|---|
| Young trees | 35 to 70 g | 11 to 22 g K₂O, 4.2 to 8.4 g P₂O₅, 2.8 to 5.6 g N | 2 to 3 times a year |
| Established trees | 70 to 140 g | 22 to 45 g K₂O, 8.4 to 17 g P₂O₅, 5.6 to 11 g N | Several times a year, up to 2 lb (907 g) per tree |
The label also prints these amounts as cup measures; this page uses the weights. It reads the label’s “up to 2 pounds” for established trees as the most one tree receives in a year. Start at the low end of each range. Use it on trees only where a soil or leaf test shows potassium is low: Penn State Extension says an apple tree, after it reaches maturity, usually requires only nitrogen. It is not a nitrogen source for trees: 140 g supplies 11 g of nitrogen, while Iowa State Extension gives 0.1 lb (45 g) of actual nitrogen per year of tree age, up to 1 lb per tree.
Beds and fields: size it by a soil test
Formula. Pounds of product = pounds of potash (K₂O) your soil test recommends ÷ 0.32. Multiply by 453.6 for grams. Apply it before planting, broadcast and worked in. For an established matted-row bed, the Mid-Atlantic recommendations apply potash at renovation.
| Source and system | Low | Medium | High | Very high |
|---|---|---|---|---|
| Mid-Atlantic: plasticulture, and new and established matted rows | 165 | 115 | 65 | 0 |
| UF/IFAS, Florida (Mehlich-3: low 35 ppm or less, medium 36–60, high above 60) | 150 | 100 | 0 | Not used (three levels) |
| Oregon State EM 9234: June-bearing, before planting, western Oregon and Washington (soil K below 75 ppm, 75–175, above 175) | 100–120 | 80–100 | 0–80 | Not used (three levels) |
| K₂O recommended per acre | This product per acre | This product per 100 sq ft |
|---|---|---|
| 50 lb | 156 lb | 163 g (0.36 lb) |
| 100 lb | 313 lb | 325 g (0.72 lb) |
| 120 lb | 375 lb | 391 g (0.86 lb) |
| 150 lb | 469 lb | 488 g (1.08 lb) |
| 165 lb | 516 lb | 537 g (1.18 lb) |
Mid-Atlantic figures are from the Strawberries section of the Mid-Atlantic Commercial Vegetable Production Recommendations. UF/IFAS figures are from its 2024 strawberry nutrient recommendations (SL517), and the Oregon and Washington figures from Oregon State’s strawberry nutrient management guide (EM 9234). In California, the CDFA and UC Davis guidelines consider ammonium acetate soil-test potassium above 200 ppm high, needing little or no potash. Soil-test labs define low, medium, and high differently, so use the recommendation printed on your own report, and apply no more potash than it calls for: in University of Florida IFAS trials, potassium rates above the recommendation reduced strawberry fruit size and yield. Each pound of potash from this product also brings 0.375 lb of phosphate and 0.25 lb of nitrogen.
Nitrogen and calcium come from other fertilizers
At the label’s per-plant rate, this product supplies only 0.24 g of nitrogen per plant. Oregon State Extension gives new strawberry plantings 0.5 to 0.8 oz of nitrogen per 10 feet of row in the first year, about 1.4 to 2.3 g per plant at 1-foot spacing, and established June-bearing beds 0.4 to 0.6 oz per 10 feet of row at renovation. For home gardens, Clemson Extension sidedresses calcium nitrate at 3 lb per 100 feet of row about a month after planting if new plants are light green and slow, and at 3 to 4 lb per 100 feet of row between mid-August and mid-September after renovation. Use ammonium sulfate rather than calcium nitrate for blueberries. For calcium in soil, lime to the pH your soil test calls for, or use gypsum where calcium is low and pH is already on target.
Hydroponic solutions
Formula. Grams of product = (potassium target in ppm − potassium already in your water in ppm) × liters of final solution ÷ 265.6. Multiply US gallons by 3.785 to get liters. The label gives no hydroponic rate, so dose this product to your recipe’s potassium target; calcium, magnesium, and most of the nitrogen come from other ingredients in a separate stock.
University strawberry recipes differ. The Yamazaki solution, used in a 2025 Arizona State University deep-water-culture study of strawberries (Ries, Meng, and Park, HortScience), targets 77 ppm nitrogen, 24 ppm phosphorus, 117 ppm potassium, 40 ppm calcium, and 12 ppm magnesium. University of Florida IFAS grew soilless strawberries on its hydroponic tomato recipe: 70 ppm nitrogen, 50 ppm phosphorus, 120 ppm potassium, 90 ppm calcium, and 40 ppm magnesium early in the season, with nitrogen and potassium raised to 150 and 200 ppm during fruiting. Dosed to the Yamazaki solution’s 117 ppm potassium, this product supplies the following:
| Nutrient | From this product at 0.44 g/L | Yamazaki solution | Supply the difference with |
|---|---|---|---|
| Potassium (K) | 117 | 117 | Nothing further |
| Phosphorus (P) | 23 | 24 | Nothing further |
| Nitrogen (N) | 35 (32 nitrate, 3.5 ammoniacal) | 77 | Calcium nitrate, in its own stock |
| Calcium (Ca) | 0 | 40 | Calcium nitrate, in its own stock |
| Magnesium (Mg) | 0 | 12 | Magnesium sulfate (Epsom salt) |
| Iron (Fe) | 2.2 | 1.95 | Nothing further |
| Manganese (Mn) | 0.88 | 0.54 | None; about 1.6 times the solution |
| Zinc (Zn) | 1.3 | 0.32 | None; about 4 times the solution |
| Boron (B) | 0.44 | 0.38 | Nothing further |
| Copper (Cu) | 0.22 | 0.05 | None; about 4 times the solution |
| Molybdenum (Mo) | 0.004 | 0.01 | Only if a water or tissue test calls for it |
Calcium and nitrogen. Calcium nitrate 15.5-0-0 adds 190 ppm calcium and 155 ppm nitrogen for each gram per liter. Raising calcium to the Yamazaki 40 ppm from water with none takes 0.21 g per liter and brings total nitrogen to about 68 ppm, close to the solution’s 77. The more calcium your water already holds, the less calcium nitrate you add and the further nitrogen falls short; then the recipe needs another nitrate source without calcium or potassium, so email us for help. Magnesium sulfate (Epsom salt, about 10% magnesium) at 0.12 g per liter adds about 12 ppm magnesium; keep it out of the calcium stock. On the UF/IFAS fruiting targets (200 ppm potassium, 90 ppm calcium) the same arithmetic gives 0.75 g of this product and 0.47 g of calcium nitrate per liter from calcium-free water, about 134 ppm nitrogen in all.
Micronutrients. At the Yamazaki dose the product supplies about as much iron and boron as the solution, more manganese, about 4 times the zinc and copper, and less molybdenum. Do not add a micronutrient mix; add any micronutrient only if a water or tissue test calls for it. In a recirculating system, replace the solution on schedule rather than topping it up with this product.
More potassium is not better. In the 2025 study, raising potassium from 117 to as much as 348 ppm, which raised EC from 1.0 to 1.9 dS/m, gave no benefit in growth, yield, or fruit quality; at 348 ppm one cultivar yielded 34% fewer fruit, and fruit were smaller in both. University of Florida IFAS also cautions that high potassium interferes with calcium uptake. Dose to your recipe’s target, not above it.
EC and pH. Strawberries are sensitive to salt: FAO lists a soil salinity threshold of 1.0 dS/m for strawberry, with yield falling about 33% for each unit above it. The University of Arizona Controlled Environment Agriculture Center lists an EC of 1.0 dS/m or less and a pH of 5.5 to 6.0, notes that growers often flush when root-zone EC exceeds 1.2, and says higher EC may suit some cultivars. Oklahoma State’s hydroponics table lists a higher EC, 1.8 to 2.2 mS/cm, at pH 6.0, and advises checking pH and EC daily and replacing the solution every two weeks. Start at the low end, measure your own solution, and watch the plants.
Separate stocks. Penn State Extension keeps calcium in a different stock tank from phosphates and sulfates, because they form precipitates that clog emitters. This product carries phosphate, so keep its concentrate apart from calcium nitrate or Cal-Mag. A 1:100 stock for the Yamazaki potassium target is about 44 g per liter from potassium-free water, below the roughly 64 g per liter premix stock in the UF/IFAS tomato recipe.
Foliar sprays
This page gives no foliar rate. The label’s foliar directions give an amount per plant but not how much water to mix it in, so this page does not restate them. None of the university sources used for this page gives a foliar rate for a fertilizer of this kind on strawberries. If you plan to spray, email questions@greenwaybiotech.com with your crop and sprayer volume first.
Containers, hanging baskets, and towers
The label gives no rate for plants in containers of potting mix, so this page gives none. Email us with your container size and growing mix before using it there. For strawberries in raised beds of garden soil, use the per-plant rate or size the bed by a soil test.
How to use Strawberry Fertilizer 8-12-32
- Test and plan. Get a soil test for beds, fields, and fruit trees, or a water test for nutrient solutions. Adjust soil pH if the test calls for it, to 6.0 to 6.5 for strawberries or 4.5 to 5.5 for blueberries, and plan nitrogen and calcium from other fertilizers.
- Pick one basis and weigh the dose. Use 3 g per berry plant, the label’s per-tree amounts, your soil test’s potash recommendation divided by 0.32 for a bed, or your solution’s potassium target. The calculator below does the arithmetic.
- Apply it. Per plant or per tree: spread it on the soil, keep it off crowns and leaves, and water it in. Beds: broadcast it and work it in before planting; the Mid-Atlantic recommendations apply potash to established matted-row beds at renovation. Solutions: dissolve it on its own and keep its concentrate in a different stock tank from calcium nitrate or Cal-Mag.
- Time it to the planting. New strawberry plantings: at planting and every 4 to 6 weeks until just before the first harvest. Established June-bearing beds: the label gives no schedule for them; Oregon State and Iowa State Extension feed after harvest, at renovation, not in spring, and a soil test sizes that feeding. Trees: as often as the label states for young or established trees.
- Repeat only as the basis says. Soil-test amounts: once per season, then retest. Solutions: Oklahoma State Extension advises checking pH and EC daily and replacing the solution every two weeks.
Calculator & choosing a size
Formulas. Berries per plant: grams of product = number of plants × 3. Trees: grams = number of trees × 35 to 70 (young) or 70 to 140 (established), starting at the low end. Beds by soil test: pounds of product = pounds of potash (K₂O) recommended for the area ÷ 0.32. Solutions: grams of product = (potassium target − potassium in your water, in ppm) × liters of final solution ÷ 265.6. Multiply pounds by 453.6 for grams.
Worked examples. 25 strawberry plants at the label rate: 25 × 3 = 75 g per application, supplying 24 g of potash and 6 g of nitrogen; a 1 lb bag covers it and about 5 more applications like it. Four established apple trees: 4 × 70 = 280 g to start (the label allows up to 560 g); a 1 lb bag covers the starting amount. A 200 sq ft bed whose soil test recommends 3 lb of potash per 1,000 sq ft: 0.2 × 3 = 0.6 lb of K₂O, ÷ 0.32 = 1.88 lb (850 g) of product, supplying 102 g of phosphate and 68 g of nitrogen; a 2 lb bag covers it. A 50-gallon fresh batch at the Yamazaki solution’s 117 ppm potassium, from water with no potassium: 117 × 189.3 L ÷ 265.6 = 83.4 g of product, adding 35 ppm nitrogen and 23 ppm phosphorus; a 1 lb bag covers it, and calcium nitrate for 40 ppm calcium from calcium-free water is 39.8 g in the separate stock. A 30-gallon injector stock at 1:100 (3,000 gallons of final solution) at 117 ppm potassium, from water with 5 ppm: 10.56 lb (4,788 g) in the stock tank, 160 g per gallon of stock; a 25 lb bag covers it, and the calculator also shows any lower-price combination of smaller bags.
| Bag size | Per-plant doses of 3 g |
|---|---|
| 1 lb (454 g) | About 150 |
| 2 lb (907 g) | About 300 |
| 5 lb (2.27 kg) | About 760 |
| 10 lb (4.54 kg) | About 1,510 |
| 25 lb (11.3 kg) | About 3,780 |
The calculator below asks what you are feeding and how many plants or trees, how large your bed is and what potash your soil test recommends, or the volume and potassium target of your nutrient solution. It applies the label’s per-plant or per-tree rate, or your test result or target, states the nutrients supplied, and recommends the smallest single bag that covers one application or batch (or the lowest-price set of bags when no single bag does), plus a lower-price bag combination when one exists. For trees it sizes the bag to the low end of the label range. Prices, tax, and shipping are confirmed at checkout, and availability is confirmed when you add to cart.
The calculator needs JavaScript. If it does not appear, use the rate tables and formulas above to choose a size.
How Strawberry Fertilizer 8-12-32 works
Potassium is the nutrient this product supplies most of. University of Minnesota Extension explains that potassium helps regulate the opening and closing of leaf stomata, which controls water loss and gas exchange, maintains turgor, and enhances the movement of sugars and starch in the plant. This product supplies 4 parts potash to 1 of nitrogen, and 90% of its nitrogen is nitrate.
Nitrogen is where strawberry programs go wrong most often. University of Minnesota Extension says nitrogen promotes leaf and runner growth and can reduce fruit quality, Oregon State Extension says spring fertilizing increases leaf growth without more or larger berries, and NC State Extension reports that nitrogen beyond the optimum does not raise yield but does increase fruit rot. That is why university guides feed established June-bearing beds after harvest, and why this page keeps nitrogen a separate decision.
Sweetness is set mostly by the variety, by how ripe the berry is when picked, and by light and temperature. Oregon State Extension notes that flavor is much improved when fruit is left to ripen on the plant. University of Florida IFAS strawberry trials found that potassium fertilization had minimal effect on fruit size and sugar content. Correcting a potassium shortage matters; extra potassium beyond the crop’s need did little for sweetness in those trials.
Tip burn on new leaves and calyx burn are calcium problems inside the plant. University of Arizona researchers tied them in greenhouse strawberries to high transpiration, which keeps calcium from reaching young tissue; Ohio State notes that simply adding more calcium to the solution does not solve it. This product contains no calcium. Its phosphate comes from monopotassium phosphate: in concentrated form calcium reacts with phosphate to form insoluble calcium phosphate, which is why nutrient recipes keep calcium nitrate in its own stock tank. Once each is diluted into the final solution they can be used together. This describes plant nutrition in general; it is not a trial of this finished product.
Compare your options
Match the product to your crop and your soil or water test. Analyses are each product’s guarantee as shown on its page.
| Option | N–P₂O₅–K₂O | Potash per part nitrogen | Choose it when |
|---|---|---|---|
| Strawberry Fertilizer 8-12-32, this product | 8-12-32, chelated micronutrients | 4.0 | You grow strawberries or the other berries and fruit trees on its label and need potash with some phosphate |
| Cucumber Fertilizer 8-16-36 | 8-16-36 | 4.5 | You grow cucumbers, squash, and melons |
| Lettuce Fertilizer 8-15-36 | 8-15-36 | 4.5 | You grow lettuce and the leafy greens on its label |
| Pepper & Herb Fertilizer 11-11-40 | 11-11-40 | 3.6 | You grow peppers or the culinary herbs on its label |
| Tomato Fertilizer 4-18-38 | 4-18-38 | 9.5 | You grow tomatoes and want less nitrogen and more phosphate per pound of potash |
| Potassium Sulfate 0-0-53 | 0-0-53, 17% sulfur | No nitrogen | You need potash only, on soil already high in phosphorus |
| Monopotassium Phosphate 0-52-34 | 0-52-34 | No nitrogen | You build a solution from single salts and need phosphorus and potassium without nitrogen |
None of these contains calcium or magnesium. Each crop formula contains boron, so follow each product’s label for the crops it names.
Handling, storage & limitations
- Label caution. Keep out of reach of children. Harmful if swallowed. Avoid contact with eyes, open cuts, or sores. Avoid breathing dust. Wash thoroughly after handling.
- Protective equipment. The Safety Data Sheet recommends nitrile gloves and safety glasses with side shields, chemical splash goggles when mixing concentrated solutions, and an N95 particulate respirator when handling large amounts of powder in an enclosed space. Do not eat, drink, or smoke while handling it.
- Crop limits. The label warns that boron-containing fertilizers used on crops other than those recommended may cause serious injury, and that molybdenum can make forage toxic to ruminant animals such as cattle, sheep, and goats. Use it only on the crops the label names, and not on forage or pasture.
- Storage. Keep it in the original container, tightly sealed, in a cool, dry, well-ventilated place; the Safety Data Sheet recommends 40 to 95°F. It absorbs moisture from the air; caking is physical and does not affect its nutrient content. Store it away from heat, flames, combustible and organic materials, acids, lime, food, feed, and drinking water, and out of reach of children and animals. It contains potassium nitrate, an oxidizer that can intensify a fire involving combustibles.
- Spills and disposal. Sweep or vacuum spills without raising dust, and keep the product out of drains and waterways, where nitrate and phosphate feed algae. Use leftover product as fertilizer following the label. Triple-rinse empty containers, use the rinse water as dilute fertilizer, and dispose of the containers as local rules require.
- Use limits. Weigh every application, and follow one basis at a time: the label’s per-plant or per-tree rate, a soil test, or a solution target. It is not a complete fertilizer and contains no calcium or magnesium.
- First aid. Eyes: flush with clean running water for at least 15 minutes, lifting the eyelids, and remove contact lenses if easy to do; get medical attention if irritation or redness persists. Skin: brush off dry material, wash with soap and water for at least 15 minutes, and get medical attention if irritation persists. Inhaled: move to fresh air; get medical attention if coughing or irritation persists. Swallowed: do not induce vomiting; rinse the mouth, give one to two glasses of water if the person is conscious and alert, and contact Poison Control or a doctor immediately.
- Emergency numbers from the Safety Data Sheet. CHEMTREC 1-800-424-9300 (US, 24 hours) or +1-703-527-3887 (international); Poison Control 1-800-222-1222.
Frequently asked questions
What does Strawberry Fertilizer 8-12-32 contain?
It guarantees 8% nitrogen (7.2% nitrate, 0.8% ammoniacal), 12% available phosphate (P₂O₅), and 32% soluble potash (K₂O), plus 0.5% iron, 0.3% zinc, 0.2% manganese, and 0.05% copper, all chelated with EDTA, and 0.1% boron and 0.001% molybdenum. It contains no calcium or magnesium. Each pound supplies 145 g of potash, 54 g of phosphate, and 36 g of nitrogen.
How much should I use per strawberry plant?
The label’s soil rate is 3 grams per plant every 4 to 6 weeks, starting at planting, with the last application just before the first harvest. For 25 plants that is 75 g per application. Spread it on the soil around the plant, keep it off the crown and leaves, and water it in. The label also prints this as approximately half a teaspoon; this page uses the weight because the weight of a teaspoon of this product has not been measured. For large or closely spaced beds, size the bed by a soil test instead.
When should I feed June-bearing, everbearing, and day-neutral strawberries?
New plantings of any type follow the label: at planting, then every 4 to 6 weeks until just before the first harvest. The label gives no schedule for established June-bearing beds. Oregon State Extension advises no spring fertilizing unless the planting is not thriving, because it increases leaf growth without more or larger berries, and Iowa State Extension feeds them during renovation, right after the last harvest; a soil test sizes that feeding. Oregon State feeds day-neutral and everbearing plants once a month for three months after spring growth begins. The label schedule stops just before the first harvest, so email us before feeding plants that keep fruiting after that.
How much should I use on a strawberry bed or field?
Size it by a soil test: pounds of product equal the pounds of potash (K₂O) your test recommends, divided by 0.32, applied before planting and worked in; the Mid-Atlantic recommendations apply potash to established matted-row beds at renovation. For example, 3 lb of potash per 1,000 sq ft on a 200 sq ft bed is 1.88 lb of product. The Mid-Atlantic recommendations call for up to 165 lb of potash per acre on low-potassium soil and University of Florida IFAS up to 150 lb, less as the soil tests higher and none on the highest-testing soils. Use the figure on your own report.
Can I use it on blueberries and cranberries?
Only as a potash and phosphate supplement. Both are on the label, but 90% of this product’s nitrogen is nitrate. Oregon State Extension says blueberry plants cannot take up or use nitrate nitrogen, University of Florida IFAS that blueberries prefer ammonium, and UMass Extension that cranberries preferentially use ammonium nitrogen. Use it on them only where a soil or leaf test shows potassium or phosphorus is low, supply nitrogen as ammonium sulfate, and keep blueberry soil at pH 4.5 to 5.5. Do not pile fertilizer against the crown.
Do I still need a nitrogen fertilizer?
Usually, yes. At the label rate this product supplies 0.24 g of nitrogen per plant, while Oregon State Extension gives new strawberry plantings 0.5 to 0.8 oz of nitrogen per 10 feet of row in the first year, about 1.4 to 2.3 g per plant at 1-foot spacing. For home gardens, Clemson Extension sidedresses calcium nitrate at 3 lb per 100 feet of row about a month after planting if new plants are light green and slow, and at 3 to 4 lb per 100 feet of row after renovation. Too much nitrogen is also a problem: NC State Extension reports that nitrogen beyond the optimum does not raise yield but does increase fruit rot. Use ammonium sulfate for blueberries.
How do I use it in a hydroponic system?
Dose it to your solution’s potassium target: grams = (target ppm K minus the K in your water) × liters of final solution ÷ 265.6. At the Yamazaki strawberry solution’s 117 ppm potassium that is 0.44 g per liter, which also adds 35 ppm nitrogen and 23 ppm phosphorus. Supply calcium and the rest of the nitrogen with calcium nitrate in a separate stock tank, and magnesium with magnesium sulfate. University sources differ on EC: the University of Arizona CEAC lists 1.0 dS/m or less, while Oklahoma State lists 1.8 to 2.2 mS/cm. At this dose the product supplies about 4 times the zinc and copper of the Yamazaki solution, so do not add a micronutrient mix.
Will it make my strawberries sweeter?
No fertilizer can promise that. Sweetness depends mostly on the variety, how ripe the berry is when picked, and light and temperature; Oregon State Extension notes that flavor is much improved when fruit ripens on the plant. University of Florida IFAS trials found that potassium fertilization had minimal effect on fruit size and sugar content. The CDFA and UC Davis guidelines note that fruit from potassium-deficient plants tastes insipid, so correct a shortage your soil test shows; potash beyond that did little for sweetness in the Florida trials.
Can I mix it with Cal-Mag or calcium nitrate?
Not as concentrates. Calcium reacts with the phosphate in this product to form insoluble calcium phosphate, which settles out and can clog emitters. Dissolve each product separately, keep them in different stock tanks, and dilute each into the final solution, where they can be used together. Then check the final solution for cloudiness, EC, and pH. In the garden, apply them as separate feedings.
Which other crops can I use it on?
Besides strawberries, the label names raspberries, blackberries, blueberries, and cranberries at 3 g per plant, and cherries, apples, pears, peaches, and plums at 35 to 70 g per young tree 2 to 3 times a year or 70 to 140 g per established tree several times a year, up to 2 lb per tree. Use it on trees only where a soil or leaf test shows potassium is low; it is not a nitrogen source for them. Because it contains boron, the label warns that use on other crops can cause serious injury, and because it contains molybdenum, do not use it on forage or pasture. The label gives no rate for containers, and its foliar direction states no water volume, so email us before using it either way.
Related guides & articles
- What Does Potassium Do for Plants?: how potassium works in the plant, what a shortage looks like, and the main potash sources.
- Calcium in Plants: Function, Deficiency & Fertilizers: why calcium moves with water, why tip burn is a delivery problem, and why calcium and phosphate concentrates are kept apart.
- Acid-Loving Plant Fertilizer: pH, Sulfur & Iron: how to bring blueberry soil into range with sulfur, and why blueberries need ammonium nitrogen.
- Sulfate vs. Chelated Fertilizers: how chelated and sulfate forms of iron, zinc, manganese, and copper differ, and how soil pH affects them.
Articles give background. For this product, use the rates and documents on this page.
Product documents & sources
- Product label (PDF): the CDFA-approved label, dated March 25, 2025, with the guaranteed analysis, crop list, cautions, and directions for this product. How this page uses its per-plant, per-tree, and foliar directions is explained in Application rates.
- Safety Data Sheet (PDF): handling, storage, first aid, and emergency numbers. Version 1.0, issued April 2026.
- Heavy-metal analysis (PDF): an independent laboratory test of this product by AgroLab/Matrix Sciences, sample received December 16, 2024, reviewed December 20, 2024. Arsenic, cadmium, and lead in the tested sample were well below California’s limits for fertilizers.
Where the rates and statements on this page come from
The per-plant and per-tree rates, crop list, and cautions come from the product label, the safety statements from the Safety Data Sheet, the heavy-metal limits from the California regulation listed last, and the timing, soil-test, crop, hydroponic, and plant-nutrition statements from the university, agency, and journal publications below, which explain crop nutrition but do not evaluate or endorse this product.
- Oregon State University Extension, Growing Strawberries in Your Home Garden (EC 1307): timing by strawberry type, spring feeding of established beds, first-year and renovation nitrogen, placement, and ripening and flavor.
- Iowa State University Extension, Fertilizing Tree and Small Fruits in the Home Garden: renovation feeding of June-bearers, the effects of spring feeding, and fruit-tree nitrogen by tree age.
- University of Minnesota Extension, Strawberry Nutrient Management: how nitrogen affects leaf growth and fruit quality.
- NC State Extension, Gray Mold or Botrytis Rot of Strawberry: nitrogen beyond the optimum and fruit rot.
- NC State Extension, Southern Regional Strawberry Plasticulture Production Guide (2024): plants per acre at 12-inch, double-row spacing.
- Mid-Atlantic Commercial Vegetable Production Recommendations, Strawberries (University of Maryland Extension copy): potash by soil-test level, renovation timing, soil pH, and salt sensitivity.
- University of Florida IFAS, Nutrient Management Recommendation Series: Strawberry (SL517, 2024): Florida potash recommendations by Mehlich-3 soil test.
- University of Florida IFAS, Fertilization of Strawberries in Florida (CIR1141, rev. 2023): potassium rates above the recommendation reducing fruit size and yield.
- Oregon State University Extension, Strawberry Nutrient Management Guide for Oregon and Washington (EM 9234): potash recommendations by soil test.
- CDFA Fertilizer Research and Education Program with UC Davis, California Fertilization Guidelines: Strawberry: soil-test potassium thresholds, potash removal by fruit, and the flavor of potassium-deficient fruit.
- Clemson Cooperative Extension, Growing Strawberries in South Carolina (HGIC 1405): soil pH and the calcium nitrate sidedress and renovation rates.
- Oregon State University Extension, Growing Blueberries in Your Home Garden (EC 1304): nitrate nitrogen, soil pH, salt sensitivity, and keeping fertilizer off the crown.
- University of Florida IFAS, Nutrition and Fertilization Practices for Southern Highbush Blueberry in Florida (HS1356): blueberries’ preference for ammonium nitrogen.
- University of Minnesota Extension, Growing Blueberries in the Home Garden: ammonium sulfate for blueberries and sulfur before planting.
- UMass Cranberry Station, Nutrient Management, cranberry best management practices (2010): cranberries and ammonium nitrogen.
- Oregon State University Extension, Growing Blackberries in Your Home Garden (EC 1303) and Growing Raspberries in Your Home Garden (EC 1306): nitrogen as the main nutrient for brambles.
- Penn State Extension, Nutritional Requirements of Apples in Home Fruit Plantings: mature trees and nitrogen.
- University of Minnesota Extension, Potassium for Crop Production: the roles of potassium in the plant.
- University of Florida IFAS (Agehara), potassium research report to the Florida Strawberry Research and Education Foundation, 2024–25: potassium fertilization and fruit size and sugar content.
- Ries, Meng, and Park, HortScience 60(2):198–204, 2025: the Yamazaki strawberry solution and the effect of raising potassium.
- University of Florida IFAS, NFREC-Suwannee Valley, Comparison of Bare-Root and Plug Strawberry Transplants in Soilless Culture (Hochmuth et al.): the early-season and fruiting solution targets.
- University of Florida IFAS, Nutrient Solution Formulation for Hydroponic Tomatoes in Florida (HS796/CV216): premix stock strength, and the caution that potassium interferes with calcium uptake.
- University of Florida IFAS, Fertilizer Management for Greenhouse Vegetables (HS787/CV265): the magnesium sulfate rate used in the calculator.
- Penn State Extension, Hydroponics Systems: Using the Two Basic Equations to Calculate a Nutrient Solution Recipe: keeping calcium in a different stock tank from phosphates and sulfates.
- University of Arizona Controlled Environment Agriculture Center, Hydroponic Strawberry Information: Irrigation: solution EC, flushing, and pH.
- University of Arizona Controlled Environment Agriculture Center, Hydroponic Strawberry Information: Tip Burn: tip and calyx burn and transpiration.
- Ohio State University Controlled Environment Agriculture, Tipburn: why more calcium in the solution does not solve tip burn.
- Oklahoma State University Extension, Electrical Conductivity and pH Guide for Hydroponics (HLA-6722): the strawberry EC and pH range and solution monitoring.
- FAO, Agricultural Drainage Water Management in Arid and Semi-Arid Areas (Irrigation and Drainage Paper 61), Annex 1: the strawberry salinity threshold and yield loss.
- California Code of Regulations, Title 3, § 2302, Non-Nutritive Standards: California’s arsenic, cadmium, and lead limits for fertilizers.
Rates and sources reviewed October 16, 2026.
Help choosing & next step
Not sure whether to feed per plant or by soil test, how to time feedings for your strawberry type, or how to fit this product into a nutrient recipe? Email your crop, growing method, and soil or water test results to questions@greenwaybiotech.com, or call (562) 351-5168, Monday to Friday, 7 AM to 5 PM Pacific, and we will work through it with you.
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Greenway Biotech, Inc. is a family-owned company that has blended and packaged specialty fertilizers and soil amendments in California since 1989, today from Madera.
