Tomatoes grow best in slightly acidic soil with a pH level between 6.0 and 7.0 � optimum is between 6.5 and 7.0. If your soil�s pH isn�t within that range, make proper adjustments. To lower your soil�s pH, work sulfur into the soil. To raise your soil�s pH, work lime into the soil. An appropriate pH is an important component to preparing the soil for planting tomatoes.

Evaluate nutrients

Check soil test results for an even balance between nitrogen, phosphorus, and potassium, all necessary for strong tomato production. Evaluating nutrients will go a long way in preparing your soil because you will know what you need to add.

Nitrogen

Nitrogen helps your tomatoes maintain healthy, green leaves. Yellowed older leaves and slowed growth indicate nitrogen deficiency. But when you apply too much nitrogen before fruit is set, stems become quite large, leaves are deep green and soft, and there are few if any flowers. Tomatoes need about 1-3âÂÂ4 pounds of nitrogen per 500 square feet. Incorporate nitrogen into soil just before planting.

Good organic fertilizer sources of nitrogen:

alfalfa meal

blood meal

compost

feather meal

fish meal

legumes

leaf mold

Good inorganic nitrogen sources:

ammonium nitrate

ammonium sulfate

anhydrous ammonia

calcium nitrate

potassium nitrate

sodium nitrate

urea

Phosphorus

Phosphorus helps your tomatoes develop strong root systems, build disease resistance, and cultivate fruit and seed formation. Slow, stunted growth and reddening stems and foliage indicate a phosphorus deficiency. Incorporate phosphorus-containing fertilizers into the soil before planting, rather than sprinkling them on the surface.

Good organic fertilizer sources of phosphorus

bone meal

compost

Good inorganic phosphorus sources

rock phosphate

super phosphate

Potassium

Potassium helps promote growth and disease resistance in your tomato plants. Weak plants and slow growth indicate a potassium deficiency. In more severe cases, leaf edges will brown. An easy way to amend the soil is to add wood ash, which is 5% potassium. Best rate is about 10-15 pounds to a 300 square foot bed. Work in wood ash in the fall or winter.

Good organic fertilizer sources of potassium

wood ash

granite dust (also called rock potash) � slow-releasing leaf mold

Good inorganic potassium sources

potassium sulfate

rock sand

Compost

Compost is broken-down organic matter. It�s not particularly high in nutrients but it�s a fantastic way to improve your soil. Compost improves soil structure, increases its cultivability, aids in nutrient retention, reduces compaction, attracts earthworms, increases microbes, and protects plants from disease. Adding compost is the singular most important step you can take to preparing your soil for planting tomatoes.