Once you've had a fresh, flavorful tomato from your garden, it's hard to go back to supermarket tomatoes when the growing season is over. The good news is it's possible to grow tomatoes (Solanum lycopersicum) indoors all year long. With good artificial lighting or a bright enough window, you can grow tomatoes in your home even during the wintertime.
There are many types of tomatoes to choose from. The small patio varieties are best for growing indoors, since their containers don't take up too much space. Likewise, determinate tomato plants generally do not get as large as indeterminate plants. However, determinate plants produce all their fruit at once whereas indeterminate plants continuously set and ripen fruit. So to have a consistent supply of tomatoes with determinate plants, plant a few varieties that fruit at different times or sow new seeds every month or two. Tomato plants generally have a fast growth rate. Outdoors, they should be planted in the spring after the threat of frost has passed. But indoors, you can try planting them any time.
|Botanical Name||Solanum lycopersicum|
|Common Name||Tomato, heirloom tomato|
|Plant Type||Annual, vegetable|
|Mature Size||3–6 ft. tall, 2–3 ft. wide|
|Soil Type||Loamy, well-drained|
|Soil pH||Acidic, neutral|
|Hardiness Zones||10-11 (USDA)|
|Native Area||South America, Central America|
|Toxicity||Toxic to people and animals|
A container that is at least 12 inches deep should be sufficient for most tomato plants. But check the space requirements for your specific variety. In general, the larger the tomato, the larger the pot you will need to achieve a harvest. The container must have ample drainage holes, or the plant can develop root rot from soil that stays wet for too long. An unglazed clay container is ideal because it also allows excess moisture to escape through its walls.
When planting seeds indoors, plant them about 1/4 inch deep in a shallow growing tray filled with seed-starting mix. Once seedlings emerge and develop two true leaves, transfer them to small pots. When planting a young tomato plant, bury the stem up to the bottom set of leaves. Roots will form all along the stem, resulting in a stronger plant. If your tomato plant variety requires support, install a stake or tomato cage in the container.
Tomatoes are self-pollinating, meaning they don’t need insects to pollinate for them. However, you can help your indoor plants by mimicking the wind that would naturally facilitate their pollination process. Gently shake the stems every day or so when the plants are in bloom, or place a small oscillating fan in the area to act like wind.
Tomato plants like a lot of light. So when growing them indoors, place them by your brightest window. A large south-facing window is ideal. Rotate the pots every day until the seedlings begin to flower and set fruit. This will help prevent the stems from becoming leggy and too flimsy to support fruit. If you don't have a window that will work, install grow lights above your tomato plant containers. It helps to have a method for raising and lowering the lights. Again, this will prevent the plants from becoming too leggy by trying to reach up toward the light. The ideal position for lighting is about 1 to 2 inches above the tops of the seedlings until they begin to flower and fruit.
Tomatoes thrive in an organically rich, loose soil with a slightly acidic to neutral soil pH. For container plantings, choose a quality all-purpose organic potting mix. A mix made especially for vegetables often works well.
These plants also like a lot of water but they do not like wet feet so good drainage is important. Aim to keep the soil lightly moist but not soggy. A consistent level of moisture will help to prevent the tomatoes from splitting. So check often to see whether your containers need water. If the soil feels dry about an inch down, it’s time to water.
Temperature and Humidity
One easy part about growing tomatoes indoors is they like average room temperatures between around 65 and 80 degrees Fahrenheit. Humidity also typically isn’t an issue indoors. Just be sure to protect your plants from drafts, as well as airflow from heating and cooling vents.
Tomatoes are heavy feeders. Use an organic slow-release fertilizer on your plants, following label instructions.
There are many tomato plant varieties that come in different fruit sizes, appearances, tastes, and more. They include:
- Beefsteak Red: This plant features large tomatoes with a bright red color and thick flesh. The plants grow quite large and typically need staking or other support.
- Cherry: This variety yields lots of small tomatoes that are especially juicy and flavorful.
- Roma: The fruit from this plant is often used in sauces and pastes. The tomatoes are egg-shaped and more fleshy than juicy.
- Patio: This is a small hybrid variety that’s ideal for containers. The tomatoes are compact but flavorful, and the whole plant only grows to around 2 feet tall.
There are many cherry and patio tomato varieties available today with new hybrids being introduced every year. Plants that produce abundant but smaller fruit are easier to manage indoors. Some tried and true favorites include:
- SunGold: Indeterminate, thin-skinned bite-size yellow variety; round cherry type
- Jelly Bean: Indeterminate with heavy clusters of up to 30 fruits that weigh 1/4 to 1/2 ounce each; comes in both red and yellow varieties; grape cherry type
- Supersweet 100: Indeterminate; long strands of up to 100 super sweet round cherry-type tomatoes weighing about 1 ounce each; requires staking
- Tommy Toe: Indeterminate heirloom cherry type, round or oval in shape and weighing about 1/2 to 1 ounce each
- Pear: Indeterminate cherry type with red or yellow pear-shaped fruits; prolific yields of fruit each weighing between 1/2 and 1 ounce; requires staking
- Juliet: An indeterminate tomato with glossy red-skinned fruits that are just a bit bigger than many cherry varieties at 1 ounce each
- Jaune Flamme: Indeterminate heirloom with orange skin on fruits weighing 2 to 3 ounces each; patio type
- Green Zebra: Indeterminate; ripened fruits are green with yellow to light green stripes; good tomato flavor in the 2- to 4-ounce fruits; patio type