When buying transplants, avoid large, spindly plants already bearing flowers or fruits. Rather, choose healthy young plants with an even height-to-width ratio and of deep green color. Check plants for pests before purchase.
Add a generous portion of compost and some crushed eggshells into the hole dug for each plant. If cutworms are a concern, make a circular barrier around the base of your transplants, about an inch into the soil and at least two inches above it. This can be made of a toilet paper tube, paper, or plastic and will prevent cutworms from eating through the stem of your transplants.
Soil Nutrient Problems
If your tomato plants are large and leafy but not producing many fruits, this may be a sign of too much nitrogen in relation to phosphorus and potassium.
Signs of insufficient nitrogen are stunted growth and yellow leaves lower on the plant. Good organic amendments for nitrogen are aged manure, blood-meal, compost, and fish emulsion.
If your plants are stunted and thin with purple undersides on the leaves, this may be a sign of insufficient phosphorus. Good organic sources are phosphate rock, bonemeal, and poultry manure.
If your tomato plants are stunted with yellow-splotched leaves, this may be a sign of insufficient potassium. Good organic sources are granite meal and wood ashes.
Calcium is also important for tomato plant development and disease resistance. Good organic sources are bonemeal, eggshells, ground limestone, and wood ashes.