Plant tomatoes in a container at least 5 gallons, fill it with potting soil (not garden soil), and set it where it gets 6 to 8 hours of direct sun each day

A potted tomato needs three things to grow: a container large enough for the roots, soil that drains well, and enough light. A 5-gallon bucket works, but a 10-gallon pot gives you more room and more stable soil temperature. Fill the container with potting mix — the kind sold bagged at garden centers — not soil from your yard. Garden soil compacts in a pot and traps water around the roots.

Plant the tomato seedling or transplant deep: bury it up to the first set of true leaves. Tomatoes will grow roots all along the buried stem, which makes them stronger. Water the soil until it drains from the bottom, then let the top inch dry out between waterings. In hot weather, a large pot may need water every day.

Key Takeaways

  • Use a pot at least 5 gallons in size; 10 gallons is better for determinate varieties and gives more stable moisture.
  • Fill the pot with bagged potting mix, not garden soil, because potting mix drains and aerates better in a container.
  • Plant the seedling deep, burying the stem up to the first leaves so roots form along the buried portion.
  • Place the pot where it receives 6 to 8 hours of direct sun; tomatoes grown in shade produce fewer fruit and ripen slowly.
  • Water when the top inch of soil is dry, and may support the pot has drainage holes so water does not pool at the bottom.

Choosing the Right Container Size and Material

The minimum size is 5 gallons, but larger is better. A 5-gallon pot works for small determinate varieties (bush types that stop growing at a set height), but indeterminate varieties (vining types that grow all season) do better in 10 gallons or more. Bigger pots hold more soil, which means more water and nutrients available to the plant, and the soil temperature stays more stable on hot days.

Plastic, ceramic, fabric, and terracotta all work. Plastic and fabric warm up and cool down quickly, which is fine in most climates. Terracotta is heavy and porous — it dries out faster, so you water more often, but it looks good on a patio. Make sure the pot has at least one drainage hole in the bottom. If water sits in the pot after watering, the roots will rot.

Filling the Pot With the Right Soil

Use potting mix, not potting soil and not garden soil. Potting mix is a blend of peat moss or coconut coir, perlite, and compost. It drains well and does not compact. Garden soil is too dense for containers — it holds too much water and suffocates roots. Potting soil sold in bags is usually potting mix, but read the label to be sure.

Fill the pot to within 2 inches of the rim. Leave that space so water does not run straight off the top when you water. If you want to add slow-release fertilizer, mix it into the potting mix before planting, following the package directions. You can also add a handful of compost to the mix for extra nutrients, though potting mix alone will support a tomato for the first month or so.

Planting the Seedling Deep

Dig a hole in the potting mix deep enough to bury the seedling up to its first set of true leaves — the leaves that look like tomato leaves, not the smooth oval seed leaves that appeared first. Tomatoes grow roots along any part of the stem that is buried, so a deeper plant has a stronger root system. This is one of the biggest advantages of container growing: you can plant deeper than you would in the ground.

Gently remove the seedling from its nursery pot and loosen the roots with your fingers. Set it in the hole, fill around it with potting mix, and press gently so the soil makes contact with the roots. Water right after planting until water drains from the bottom. The soil will settle a bit over the next few days, so you may need to add a little more mix.

Positioning the Pot for Maximum Sun

Tomatoes need 6 to 8 hours of direct sun each day. Direct sun means the sun hits the leaves without shade from trees or buildings. A pot in afternoon shade or dappled light will grow, but it will produce fewer flowers and fruit, and the fruit will ripen slowly. If your patio or balcony gets less than 6 hours of sun, a tomato will struggle.

If you have a choice, morning sun is slightly better than afternoon sun in very hot climates, because the morning sun dries dew off the leaves (which reduces disease) without the intense heat of late afternoon. In cool climates, afternoon sun is fine. You can move the pot during the day if you have a small space — many people slide pots to follow the sun — but the plant will be happier if you leave it in one spot once it is established.

Watering and Drainage

Water when the top inch of soil feels dry to your touch. In warm weather, this may be every day. In cool or cloudy weather, it may be every two or three days. The goal is to keep the soil moist but not soggy. Soggy soil causes root rot; dry soil stresses the plant and can cause blossom-end rot (a dark spot on the bottom of the fruit).

Water at the base of the plant, not on the leaves. Wet leaves are more prone to fungal disease. If the pot has no drainage hole, drill one or use a pot that does. Standing water in the bottom of the pot will kill the roots within days. In very hot weather, you may need to water twice a day if the pot is small or in full sun all afternoon.

Supporting the Plant as It Grows

Most tomato varieties need support. Install a cage, stake, or trellis before or right after planting, not later. A cage or stake driven into the pot early will not damage roots. As the plant grows, tie the main stem loosely to the support with soft ties — old cloth strips work well — every 8 to 12 inches up the stem. Loose ties let the stem expand as it thickens.

Determinate varieties (bush types) need less support than indeterminate (vining) types. A determinate tomato in a 5-gallon pot may need only a small cage or stake. An indeterminate tomato in a 10-gallon pot will grow 4 to 6 feet tall and needs a sturdy cage or a stake at least 6 feet long. Plan for this before you plant.

Frequently Asked Questions

Can I use garden soil from my yard instead of potting mix?

No. Garden soil compacts in a pot and holds too much water, which causes root rot. Potting mix is designed to drain and stay loose in a container. The difference is significant — a tomato in garden soil will likely fail or produce poorly.

How often should I fertilize a potted tomato?

If you mixed slow-release fertilizer into the potting mix at planting, you may not need to fertilize again for 4 to 6 weeks. After that, feed every two weeks with a balanced fertilizer (like 10-10-10) or a tomato-specific formula, following the package rate. Potted plants need more fertilizer than in-ground plants because water drains out nutrients.

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

A cherry tomato can grow in a 5-gallon pot. A large slicing tomato (like a beefsteak) does better in 10 gallons or more because it grows larger and heavier. Determinate varieties are smaller and need less space than indeterminate varieties of the same type.

Can I plant a tomato in a pot without drainage holes?

No. Without drainage, water pools at the bottom and roots rot within days. If you like the look of a pot without holes, use it as a decorative outer pot and set a draining pot inside it.

When should I plant the tomato in the pot?

Plant a seedling or transplant in spring, after the last frost date for your area. If you start from seed indoors, plant the seed 6 to 8 weeks before your last frost date, then move the seedling to the pot once it has its first true leaves and the soil is warm.