Tomatoes grow well in pots if you use a container at least 5 gallons and fill it with soil that drains fast

A pot that is too small will dry out too quickly and stunt the plant. A 5-gallon bucket works, but a 10-gallon pot or larger gives you more room for roots and more stable soil moisture. The pot must have drainage holes in the bottom — if it does not, drill three or four holes yourself before you plant.

Fill the pot with potting soil, not garden soil from the yard. Potting soil is lighter and drains better. Garden soil compacts in a pot and holds too much water, which causes root rot. You can buy bags of potting soil at any garden center or hardware store.

Plant the tomato seedling deep — bury it up to the first true leaves. Tomatoes will grow roots along the buried stem, which makes the plant stronger. Water the soil right after planting until water drains from the bottom.

Key Takeaways

  • Use a pot that is at least 5 gallons, with drainage holes, and fill it with potting soil rather than garden soil.
  • Water when the top inch of soil feels dry to your touch, usually every one to three days depending on heat and pot size.
  • Place the pot in a spot that gets six to eight hours of direct sunlight each day, or the plant will produce fewer tomatoes.
  • Stake or cage the plant early so the stem does not break under the weight of fruit as it grows.
  • Feed the plant every two to three weeks with a balanced fertilizer once it starts flowering.

Watering and drainage matter more in pots than in the ground

Pots dry out faster than garden beds because soil is exposed on all sides. Check the soil by pushing your finger into it — if the top inch is dry, water until it drains from the bottom. In hot weather, this may be every day. In cool weather, it may be every three days.

Overwatering is the most common mistake. Soggy soil kills roots and causes blossom end rot, a dark spot on the bottom of the fruit. If the pot feels heavy and the soil is wet, wait another day or two before watering again. The soil should feel like a wrung-out sponge — moist but not waterlogged.

Water at the base of the plant, not on the leaves. Wet leaves invite fungal disease. A soaker hose or drip line works well for pots, but a watering can pointed at the soil also works.

Sunlight and temperature affect how many tomatoes you get

Tomatoes need six to eight hours of direct sunlight each day to produce fruit. A pot on a south-facing patio or deck usually gets enough. A spot that gets only three or four hours of sun will grow a tall plant with few tomatoes.

Tomatoes also need warmth. They grow best when the air is between 65 and 85 degrees Fahrenheit. If nighttime temperatures drop below 55 degrees, the plant will slow down and may drop flowers. In cool climates, move the pot to a sheltered spot or against a south-facing wall where it stays warmer.

Support the plant with a stake or cage as it grows

Tomato plants get heavy once fruit forms. Without support, the stem will bend or break. Install a stake or cage when you plant the seedling, not later — pushing a stake in after the plant is large can damage roots.

A wooden stake about 5 feet tall works for determinate varieties, which stay compact. Indeterminate varieties grow taller and do better in a cage or with multiple stakes and string. Tie the stem loosely to the support with soft material like cloth strips or plant tape — do not use wire or string that can cut into the stem.

Feed the plant once it starts to flower

Potting soil has some nutrients, but they run out as the plant grows. Once you see the first flowers, feed the plant every two to three weeks with a balanced fertilizer like 10-10-10 or a tomato-specific formula. Follow the label instructions for how much to use.

Too much nitrogen makes the plant grow leaves instead of fruit. A balanced or slightly higher phosphorus formula (the middle number) encourages flowering and fruiting. Liquid fertilizers work faster than granules, but both work.

Prune suckers and lower leaves to improve air flow

Suckers are shoots that grow in the angle between the main stem and a branch. Pinch them off when they are small — they take energy from fruit production and make the plant dense. On indeterminate varieties, remove suckers regularly to keep the plant manageable.

Remove leaves that touch the soil or stay wet from watering. These lower leaves are most likely to get fungal disease. Removing them also improves air flow around the base of the plant, which keeps the soil from staying too wet.

Harvest tomatoes when they are fully colored but still firm

Pick tomatoes when they are fully colored — red, pink, yellow, or whatever color your variety is — but still slightly firm. A tomato that is soft will not store as long. Tomatoes continue to ripen after you pick them, so you do not have to wait until they are mushy.

In late summer, when frost is coming, pick all the tomatoes on the plant, even the green ones. Bring them inside and set them on a windowsill or in a paper bag with a ripe banana — the banana releases ethylene gas, which speeds ripening. Green tomatoes will turn color over one to three weeks.

Frequently Asked Questions

Can I grow tomatoes in a pot indoors under a grow light?

Yes, but the light must be strong and close to the plant — most household lamps are too dim. A fluorescent or LED grow light placed 6 to 12 inches above the plant works. The plant still needs warmth and good air flow, so a fan helps prevent disease.

What size pot do I need for a cherry tomato versus a large slicing tomato?

Cherry tomatoes can grow in a 5-gallon pot. Large slicing varieties like Brandywine need 10 gallons or more because they have bigger root systems. Check the seed packet or plant label — it usually says the recommended pot size.

Why are my tomato flowers falling off without making fruit?

Flowers drop when the plant is stressed by temperature swings, inconsistent watering, or too much nitrogen. Keep the soil evenly moist, avoid feeding too much nitrogen, and make sure nighttime temperatures stay above 55 degrees. Bees and other insects also pollinate flowers — if you have no insects, gently shake the plant when it flowers to move pollen between flowers.

Can I reuse the potting soil from last year?

You can, but mix it half and half with fresh potting soil. Old soil loses structure and drains poorly. If the plant from last year had disease, replace the soil entirely to avoid spreading it to the new plant.

How long does it take to get tomatoes from a seedling?

From a seedling planted in spring, you will see flowers in four to six weeks and ripe tomatoes in eight to twelve weeks, depending on the variety and temperature. Seed packets list the number of days to maturity — that is how long it takes from transplant to harvest.