Start with soil that drains well and holds nutrients
The single biggest difference between tomatoes that produce and tomatoes that struggle is the soil they grow in. Tomato plants need soil that drains fast enough that water does not pool around the roots, but holds enough moisture and nutrients to feed the plant through the season. This means mixing your garden soil or potting mix with compost — aim for roughly one part compost to two parts existing soil.
If you are growing in containers, use a potting mix labeled for vegetables or tomatoes, not garden soil. Garden soil compacts in pots and blocks drainage. If you are planting in the ground, work compost into the top 8 to 10 inches of soil before you plant. Tomatoes are heavy feeders, and that organic matter breaks down over the season, releasing nitrogen and other nutrients the plant needs.
Test your soil pH if you can — tomatoes prefer slightly acidic soil between 6.0 and 6.8. If your soil is much more alkaline than that, adding sulfur or peat moss can help, but compost alone often brings pH into range over time.
Key Takeaways
- Tomatoes need at least six to eight hours of direct sunlight daily, and eight to ten hours produces better fruit and fewer disease problems.
- Water deeply and consistently — aim for one to two inches per week depending on heat and rainfall, and water the soil rather than the leaves to prevent fungal disease.
- Soil mixed with compost drains well and holds nutrients; container tomatoes need potting mix, not garden soil.
- Pruning suckers (the shoots that grow between the main stem and branches) on indeterminate varieties improves air flow and directs energy to fruit rather than foliage.
- Staking or caging tomatoes keeps fruit off the ground, reduces disease, and makes harvesting easier.
Give tomatoes six to ten hours of direct sun each day
Tomatoes are sun plants. A tomato in partial shade will grow, but it will produce fewer flowers, set less fruit, and the fruit that does develop will ripen more slowly. Six to eight hours of direct sunlight is the minimum; eight to ten hours is better. If your garden gets less than six hours, tomatoes will struggle no matter what else you do right.
Direct sun also matters for disease prevention. Leaves that stay wet longer take longer to dry, and wet leaves are where fungal diseases like early blight and septoria leaf spot take hold. Morning sun dries dew faster than afternoon sun alone. If you have a choice between a spot with six hours of morning sun and six hours of afternoon sun, choose the morning sun.
Water deeply and let the soil dry slightly between waterings
Tomatoes need consistent moisture, but not wet feet. The goal is soil that is moist an inch or two down, not soggy. Water the soil directly at the base of the plant, not the leaves. Wet leaves invite fungal disease, and water that runs off the leaves is wasted anyway.
How often you water depends on heat, rainfall, and soil type. In most climates, one to two inches of water per week — whether from rain or from you — keeps tomatoes happy. In very hot weather or sandy soil, you may need to water twice a week. In cool weather or clay soil, once a week may be enough. The test is straightforward: push your finger into the soil two inches deep. If it feels dry, water. If it feels moist, wait.
Drip irrigation or soaker hoses are better than overhead sprinklers because water goes to the roots, not the leaves. If you hand-water, water early in the morning so any splash on the leaves dries quickly.
Support tomatoes with stakes or cages to keep fruit off the ground
Tomatoes grow heavy as they fruit, and unsupported plants sprawl on the ground. Fruit that touches soil rots, gets eaten by slugs and insects, and sits in moisture that breeds disease. Staking or caging tomatoes keeps them upright, improves air flow around the foliage, and makes harvesting easier.
Determinate varieties (bush types that grow to a set size and ripen most fruit at once) usually do fine in a cage. Indeterminate varieties (vining types that grow all season) need a stake or string support and regular pruning. Drive a stake into the ground at planting time — driving it later risks damaging roots. Tie the main stem loosely to the stake with cloth strips or soft ties as it grows, leaving room for the stem to thicken.
Prune suckers on indeterminate tomatoes to direct energy to fruit
Indeterminate tomatoes grow continuously and produce side shoots called suckers where branches meet the main stem. These suckers grow into full branches if left alone, and the plant becomes a dense tangle of foliage with less fruit and more disease. Removing suckers directs the plant's energy into the main stem and existing branches, which produce more and larger fruit.
Pinch off suckers when they are small — an inch or two long — by hand. Do this once a week during the growing season. You do not need to remove every sucker on determinate bush varieties; they naturally stop growing at a set height, and the extra foliage helps shade the fruit from sunburn. But on indeterminate varieties that grow six feet or taller, regular sucker removal makes a real difference in yield and disease pressure.
Feed tomatoes every two to three weeks once they start flowering
Compost in the soil provides nutrients early in the season, but once tomatoes start flowering and setting fruit, they need more. A balanced fertilizer — something like a 5-10-10 or 10-10-10 mix — applied every two to three weeks keeps the plant fed through the season. Follow the package directions for how much to use.
Avoid high-nitrogen fertilizers, which push leafy growth at the expense of fruit. If your tomato plant is all vine and few flowers, you fed it too much nitrogen. Once flowering starts, switch to a fertilizer lower in nitrogen and higher in phosphorus and potassium, which support flowering and fruiting.
Harvest tomatoes when they show color, not when they are fully red
Tomatoes picked at the breaker stage — when they first show color but are not fully red — ripen just as well off the vine as on it, and they ripen faster indoors. This matters because it frees up the plant to set and ripen more fruit before frost. Pick tomatoes that show at least 10 to 20 percent of their final color, and let them finish ripening on a windowsill or counter at room temperature.
Late in the season, when frost is coming, pick all tomatoes that show any color and bring them inside. They will ripen indoors over the next week or two. Green tomatoes picked before frost will not ripen indoors; they need warmth and light to develop color.
Frequently Asked Questions
Why are my tomato leaves turning yellow?
Yellow leaves usually mean either nitrogen deficiency (older leaves yellow first), overwatering (soil stays wet), or early blight (yellow leaves with brown spots). Check the soil — if it is soggy, water less often. If the soil is fine and you see brown spots, remove the affected leaves and improve air flow by pruning. If leaves are straightforward pale yellow and the plant is not growing well, feed with a balanced fertilizer.
What causes blossom end rot on tomatoes?
Blossom end rot is a dark, sunken spot on the bottom of the fruit caused by calcium deficiency, which happens when watering is inconsistent. The plant cannot move calcium to the fruit if the soil dries out between waterings. Water deeply and regularly so the soil stays evenly moist, and the problem usually stops with the next fruit that sets.
Can I grow tomatoes in a pot?
Yes. Use a pot at least five gallons for determinate varieties and ten gallons for indeterminate types. Fill it with potting mix (not garden soil), water regularly because pots dry out faster than ground soil, and feed every two weeks once flowering starts. Container tomatoes need the same sunlight and support as in-ground tomatoes.
When should I stop pruning tomatoes?
Stop pruning suckers about four to six weeks before your first expected frost. At that point, the plant needs all its foliage to ripen the fruit already on the vine. Pruning late in the season removes leaves that feed the fruit and slows ripening.
Why do my tomatoes crack or split?
Cracking happens when the fruit absorbs water too fast after a dry spell, usually after heavy rain or a sudden increase in watering. Consistent moisture prevents this. Mulch around the plant to keep soil moisture even, and water regularly rather than letting the soil dry out between heavy waterings.