Tomatoes need six to eight hours of direct sunlight daily

The single most important factor in choosing where to plant tomatoes is sunlight. Tomatoes are sun-hungry plants, and they will not produce well in shade. Find a spot in your garden that gets at least six hours of direct sun each day — ideally eight or more. Morning sun is especially valuable because it dries dew off the leaves, which helps prevent fungal diseases.

Check your garden throughout the day before you plant. Watch where shadows fall at 9 a.m., noon, and 3 p.m. If a spot gets full sun in summer but will be shaded by a tree or building by late August, it may still work for early varieties, but it will not be ideal for plants that fruit into fall.

Key Takeaways

  • Plant tomatoes where they receive six to eight hours of direct sunlight each day, with morning sun preferred to dry morning dew and prevent disease.
  • Choose a location with well-draining soil that has been amended with compost or aged manure, because tomatoes rot in waterlogged ground.
  • Space plants two to three feet apart to allow air circulation around the stems and leaves, which reduces fungal problems.
  • Avoid planting tomatoes in the same spot year after year, because soil-borne diseases build up and deplete nutrients specific to tomato growth.
  • Plant near a support structure — a cage, stake, or trellis — rather than trying to add one after the plant is large and fragile.

Soil drainage and fertility matter as much as sunlight

Tomatoes will not tolerate wet feet. If water pools in your garden bed after rain, or if the soil stays soggy for days, tomatoes planted there will develop root rot and fungal diseases. Before you plant, dig a hole about a foot deep and fill it with water. If the water is still there after four hours, that spot drains too slowly for tomatoes.

If your soil drains poorly, you have two options: build a raised bed filled with fresh soil, or amend the existing soil heavily with compost or aged manure. Work three to four inches of organic matter into the top eight inches of soil. This improves drainage, adds nutrients, and creates the loose, crumbly texture tomato roots prefer.

Tomatoes are heavy feeders. They pull a lot of nitrogen, phosphorus, and potassium from the soil over a season. If you planted tomatoes in the same bed last year, the soil is depleted. Either rotate to a different bed, or work in fresh compost and a balanced fertilizer before planting.

Space plants far enough apart for air to move between them

Crowded tomatoes are sick tomatoes. When plants are too close together, air cannot circulate around the leaves and stems. This creates humid pockets where fungal diseases like early blight and powdery mildew take hold. Space determinate varieties (bush types) at least two feet apart. Space indeterminate varieties (vining types) two and a half to three feet apart.

This spacing also makes it easier to water at the soil level rather than splashing the leaves, which is another way to prevent fungal problems. Wide spacing lets you move around the plant to tie it up, prune suckers, and harvest fruit without brushing against wet foliage.

Rotate your planting location every year

Tomatoes are susceptible to several soil-borne diseases — early blight, late blight, fusarium wilt, and verticillium wilt among them. These pathogens live in the soil and build up over time if you plant tomatoes in the same spot year after year. After three or four years of continuous tomato planting in one bed, disease pressure becomes severe.

The solution is straightforward: plant tomatoes in a different bed each year, rotating through at least three or four locations. If you only have one bed, remove the top six inches of soil and replace it with fresh compost, or grow tomatoes in containers that you refill with new potting mix each season.

Install support structures before planting

Decide now whether you will use cages, stakes, or a trellis system. Install the support structure before you plant the seedling, not after. A tomato plant that is already two feet tall and spreading is hard to tie up without breaking stems. A cage or stake driven into the ground after planting can damage roots.

Determinate varieties (bush types) usually do fine with a single cage or short stake. Indeterminate varieties (vining types) need taller support — a six-foot stake, a sturdy cage, or a trellis system. Plan for the mature size of the variety you are planting, not the size of the seedling in your hand.

Protect from wind but may support good air flow

Strong wind can break stems, especially on tall indeterminate plants heavy with fruit. A spot sheltered by a fence, wall, or hedge is valuable. However, do not confuse shelter with shade. A south-facing wall that blocks wind but still receives six to eight hours of direct sun is ideal. A north-facing wall that blocks wind but also blocks sun is not.

Avoid planting tomatoes directly against a wall or fence where air cannot circulate behind the plant. Leave at least a foot of space between the plant and any structure so that air can move freely around all sides of the foliage.

Container gardening works well if bed space is limited

If you do not have suitable garden beds, tomatoes grow very well in containers. Use a pot at least five gallons in size — larger is better. Fill it with potting mix (not garden soil), place it in a spot that receives six to eight hours of direct sun, and water consistently. Containers warm up faster in spring and cool down faster in fall, which can extend your growing season at both ends.

Containers also solve the rotation problem. At the end of the season, empty the old potting mix and refill with fresh mix the next year. You can move containers to follow the sun as it shifts through the seasons, and you can move them under cover if a hard frost or hail is forecast.

Frequently Asked Questions

Can I plant tomatoes in partial shade if I live somewhere very hot?

Tomatoes in very hot climates (above 90°F regularly) can benefit from afternoon shade, but they still need a minimum of four to five hours of direct morning sun. If you shade them too much, fruit production drops sharply. A spot that gets sun until 2 p.m. and then dappled afternoon shade is a compromise, but six to eight hours of direct sun is still the target.

What if my garden bed gets wet after heavy rain?

Raised beds or containers are your best options. If you want to stay in the ground bed, amend it heavily with compost and aged manure to improve drainage, or create a slight mound in the bed so water runs off rather than pooling around the roots. You can also plant tomatoes on the south-facing slope of a hill if your garden has one.

How close can I plant tomatoes to other vegetables?

Keep tomatoes at least two to three feet from other plants so air can circulate freely. Basil and carrots are good companions and do not compete for space if you give tomatoes their full spacing. Avoid planting tomatoes near brassicas (cabbage, broccoli) or fennel, which can inhibit tomato growth.

Is it okay to plant tomatoes where I grew peppers last year?

Peppers and tomatoes are both in the nightshade family and share many of the same soil-borne diseases. It is better to rotate to a different bed. If you must use the same bed, remove and replace the top six inches of soil with fresh compost to reduce disease pressure.

Can I plant tomatoes in the same spot if I use new potting mix in a container?

Yes. Containers with fresh potting mix each year break the disease cycle because the pathogens live in the soil. This is one of the main advantages of container gardening for tomatoes.