Tomato Growing Guide

May 1, 2025 Suzanne Fellows

Introduction

Tomatoes are a favorite crop for gardeners, offering delicious fruits for fresh eating, sauces, and canning. Growing healthy tomatoes requires proper care, from planting to harvesting. Here’s everything you need to know to grow an abundant tomato harvest.

Click here to access the complete Tomato Growing Guide (PDF) for detailed information on soil preparation, planting, and long-term care.

Tomato Types and Growth Habits

• Slicer Tomatoes: Large fruits, perfect for fresh use or sauces.
• Cherry Tomatoes: Small, marble-sized fruits, great for fresh eating or drying.
• Paste Tomatoes: Thick-fleshed, oblong fruits, ideal for canning and drying.
• Pear Tomatoes: Small, pear-shaped fruits, popular for fresh use or drying.

Growth Habits:

• Determinate: Compact (3–5' tall), producing fruit in a short period—great for containers.
• Indeterminate: Grows continuously, producing fruit throughout the season—requires staking or cages.

Best Growing Conditions for Tomatoes

Soil and Sun Requirements:

• Soil pH: Between 5.5–7.0.
• Temperature: 80°F optimal for germination (tolerates 50–100°F).
• Sunlight: Full sun (at least 6–8 hours daily).
• Watering: Consistent, moderate to high during growth, lower during harvest. Use mulch to retain moisture.
• Fertilization: Use balanced organic fertilizer before planting. Avoid excess nitrogen to prevent leafy growth with little fruit.

Companion Planting:

• Good Companions: Basil, borage, chives, garlic, nasturtiums, marigolds.
• Avoid Planting Near: Brassicas, corn, potatoes, kale, fennel.

How to Plant and Grow Tomatoes

Starting Seeds Indoors:

• Timing: Sow seeds 6–8 weeks before the last frost.
• Sowing: Plant seeds ¼–½” deep in a soilless mix like Quickroot. Use heat mats and grow lights to maintain 80°F.
• Watering: Keep the seedbed consistently moist but not waterlogged.

Transplanting:

• Hardening Off: Acclimate seedlings outdoors for 7–10 days.
• Timing: Transplant when night temperatures are above 45°F.
• Spacing: Space plants about 3 feet apart for air circulation.
• Depth: Plant transplants deep—bury up to the first set of true leaves to encourage root growth.

To support vigorous growth and prevent common issues like blossom end rot, we recommend feeding with Espoma Organic Tomato-Tone 3-4-6—a slow-release organic fertilizer enriched with calcium and beneficial microbes.

Tomato Plant Care Tips

• Mulching: Use red mulching film to retain moisture and increase production.
• Staking and Pruning: Stake or cage plants and prune suckers on indeterminate varieties for better air circulation.
• Fertilizing: Feed with liquid fish and kelp every 14 days once true leaves form.
• Watering: Maintain even moisture to prevent blossom end rot.

Harvesting Tomatoes

• When to Harvest: Pick when the fruits reach their mature color and are firm. Ripe fruits easily separate from the stem.
• Post-Harvest Storage: Store at room temperature, stem-side down, and avoid refrigeration. Green tomatoes can ripen in paper bags or boxes.

Common Tomato Pests and Diseases

Pests:

• Whiteflies: Found on leaf undersides; control with strong water sprays or organic pesticides.
• Colorado Potato Beetles: Handpick or use floating row covers.
• Armyworms: Handpick or introduce beneficial insects.
• Stink Bugs: Handpick and use sticky traps.
• Hornworms: Remove by hand or use beneficial insects.
• Leaf Hoppers: Control with sticky traps or beneficial insects.
• Leaf Miners: Manage with beneficial insects and sticky traps.

Diseases:

• Blossom End Rot: Caused by calcium deficiency—maintain consistent moisture and add calcium.
• Early Blight: Water from below leaves, practice crop rotation, and use organic fungicides.
• Damping Off: Avoid overly wet seed-starting medium.

Integrated Pest Management (IPM) for Tomatoes

• Cultural Controls:

Remove plants immediately after harvest.
Rotate crops every 3 years.
Use row covers like Agribon AG15 to protect young plants.

• Physical Barriers:

Install floating row covers before pests arrive.

• Biological Controls:

Introduce beneficial insects like ladybugs and praying mantids.

FAQs About Tomato Growing

Why are my tomatoes not setting fruit?

Tomatoes may fail to set fruit due to environmental stress, such as high daytime temperatures, low night temperatures, or insufficient pollination. Temperatures above 85°F during the day or below 55°F at night can prevent flowers from being fertilized. To improve fruit set, gently shake the plants to help distribute pollen, encourage pollinators, or use a small electric pollinator. Providing consistent water and avoiding excessive nitrogen fertilizer also supports flowering and fruiting.

What is blossom end rot, and how can I prevent it?

Blossom end rot appears as a dark, sunken spot at the bottom of the tomato fruit and is caused by calcium deficiency and inconsistent watering. To prevent it, maintain even soil moisture through regular watering, mulch to retain soil moisture, and provide calcium through soil amendments or fertilizers. Avoid over-fertilizing with high-nitrogen products, which can encourage leafy growth at the expense of calcium uptake.

Should I prune my tomato plants?

Pruning is recommended mainly for indeterminate tomato varieties, which grow continuously and produce fruit throughout the season. Removing suckers (the small shoots that grow between the main stem and branches) improves air circulation, reduces disease risk, and allows the plant to focus energy on fruit production. Determinate varieties, which grow to a set size and produce all their fruit at once, generally do not require pruning.

How do I protect my tomatoes from pests and diseases?

Tomatoes are vulnerable to pests like whiteflies, hornworms, stink bugs, and leaf miners, as well as diseases such as early blight and damping-off. Effective management includes cultural practices like crop rotation and removing infected plants, using physical barriers such as floating row covers, and introducing beneficial insects like ladybugs and praying mantises. Watering at the base of plants and maintaining good spacing helps prevent fungal diseases.

When and how should I harvest tomatoes?

Tomatoes should be harvested when they reach their mature color for the specific variety and are firm but slightly soft to the touch. Ripe fruits usually separate easily from the stem when gently twisted or cut. Store harvested tomatoes at room temperature, stem-side down, to prolong freshness. Green tomatoes can be ripened indoors in a paper bag or box if needed. Avoid refrigerating tomatoes, as cold temperatures can reduce flavor and texture.