Tomato · Fertility notes
Best fertilizer for tomatoes
There is no single best fertilizer for tomatoes. Cited university sheets start with a soil test, then list rates and timing that apply to that geography. This page does not prescribe a product, blend a BioArva NPK, or rank brands. Use a lab report, local Extension guidance, and applicable labels before changing a fertility program.
Fertilizer notes on this page are source-specific ranges, not a BioArva prescription. Use a lab report, local Extension guidance, and applicable labels before changing a fertility program.
This Field Book does not recommend homemade remedies or Epsom-salt programs; use a lab report, local Extension guidance, and applicable labels before changing a fertility program.
A soil sample ready for a lab report.
Cited lab-first notes (not a kit sale)
Separate source assertions — not a BioArva average.
- Clemson HGIC 1323 (South Carolina): a soil test is the method they name for determining fertilization needs of the crop. Lab-first note — not a BioArva prescription and not a kit sale.
- Utah State (Utah): before planting, determine fertilizer needs with a soil test and then follow the recommendations given with the test report. Local-report note — not a BioArva rate and not an amendment list.
Cited pre-plant notes (source-separated, not a BioArva rate)
Separate source assertions — not a BioArva average.
- Penn State Extension (Pennsylvania): absent soil-test recommendations, they describe working in 2–3 pounds per 100 square feet of a complete fertilizer they name as 10-10-10. Source fallback — not a BioArva prescription, not a product, and not a substitute for a lab report.
- UNH (New Hampshire): they say it is better to use a soil test; lacking test data they describe 2½ pounds of a complete fertilizer they name as 10-10-10 (or the equivalent) per 100 square feet, worked in about 2 weeks before planting. Source fallback — not a BioArva prescription.
- Iowa State (Iowa): if a soil test has not been conducted, they describe incorporating 1–2 pounds of all-purpose garden fertilizer they name as 10-10-10 per 100 square feet before planting. Source fallback — not a BioArva prescription.
- Clemson HGIC 1323 (South Carolina): apply lime and pre-plant fertilizer according to soil-test recommendations; broadcast evenly and incorporate to around 6 inches. Process on their sheet — not a BioArva rate.
- Utah State (Utah): if you fertilize with compost, they describe no more than 1 inch of well-composted organic matter per 100 square feet. Source cap — not a BioArva compost program.
Cited side-dress and timing notes (not a BioArva schedule)
Separate source assertions — not a BioArva average.
- Clemson HGIC 1323 (South Carolina): they describe side-dressing 1 pound of calcium nitrate — analysis they name as 15.5-0-0 — per 100 square feet (30 feet of row) three to four weeks after planting. Source rate/timing only — not a BioArva prescription.
- Clemson HGIC 1323 (South Carolina): on sandier soil, they say this side-dress may need to be split into two applications three to four weeks apart. Condition on their sheet — not a BioArva schedule.
- Clemson HGIC 1323 (South Carolina): their sheet lists side-dressing fertilizer 4 to 6 inches away from the plants. Placement note only — not a BioArva prescription.
- Cornell (New York): their sheet lists sidedressing about 1/2 cup of a fertilizer whose analysis they name as 5-10-5 per plant, worked shallowly into the top inch, when fruits are about 1 inch in diameter and again when harvest begins. Source rate/timing — not a BioArva prescription.
- Utah State (Utah): their sheet lists side-dressing each plant with 1/2 tablespoon of a fertilizer whose analysis they name as 21-0-0, sprinkled around the plants at 4 and 8 weeks after transplanting, then watering it in. Source rate/timing — not a BioArva prescription.
- Iowa State (Iowa): their sheet lists, three to four weeks after transplanting, a dilute fertilizer solution: 1–2 tablespoons of a fertilizer whose analysis they name as 10-10-10 (or a similar analysis) dissolved in a gallon of water, or a water-soluble fertilizer. Source method — not a BioArva prescription.
- UGA C1089 (Georgia): they describe a first fertilization at planting time, and not again until pollination has taken place and dime-sized fruit has appeared. Timing on their sheet — not a BioArva calendar and not an outcome promise.
- Arizona Extension (Arizona): their sheet lists a conditional timing note: generally, a plant fertilized early in its life is described as not fertilized after the first fruit is set. Conditional source timing note — not a BioArva stop rule and not a BioArva prescription.
Cited high-nitrogen patterns (not a diagnosis of a plant)
Separate source assertions — not a BioArva average.
- Penn State Extension (Pennsylvania): their sheet describes luxuriant foliage with delayed flowering and fruiting in the context of more fertilizer or a high-nitrogen fertilizer. Source-observed pattern only — not a diagnosis, not feed advice, and not a BioArva prescription.
- UNH (New Hampshire): their sheet describes lush, vigorous foliage with little fruit production in the context of excess nitrogen. Source-observed pattern only — not a diagnosis, not feed advice, and not a BioArva prescription.
- Iowa State (Iowa): their sheet describes excessive vegetative (leafy) growth and possible inhibited fruit development in the context of over-fertilization. Source-observed pattern only — not a diagnosis, not feed advice, and not a BioArva prescription.
- Cornell (New York): their sheet lists high-nitrogen fertilizers as those with three or more times nitrogen than phosphorus or potassium. Ratio context only — not a BioArva prescription and not a product choice.
Sampling notes live on garden soil test. In-season water and support stay on tomato plant care.
Save this bed. See it coming next year.
Your checks stay in the Field Book so next season is not a guess.
How we know — methodology. Ranges and assertions are cited per source, not blended.