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How To Grow Tomatoes Indoors

Updated November 11, 2021 by Mark Marino

When you know how to grow tomatoes indoors, you can enjoy the taste of summer all year long! Growing tomatoes indoors is more challenging than growing tomatoes outside, but with proper care of your tomato plants, you can grow tomatoes all year long provided you have a sunny window or are willing to use artificial light. Tomatoes are a delicious member of the nightshade family, and while other nightshade members are decidedly not suitable for eating, tomatoes are enjoyed the world over and are celebrated ingredients for many types of cuisine. Where would Italian food be without them?

Growing tomatoes indoors requires careful preparation and some know-how. We’ll explore how to grow tomatoes in a sunny window using the following tips and techniques. 

Types of Tomatoes to Plant

Whether you prefer cherry tomatoes, heirloom tomatoes, or other tomato varieties, you can grow any type of tomato plant that you have room for. Keep in mind that some types can grow 10 feet or taller. Because of tomato plants’ need for direct sunlight, many types, like indeterminate tomato plants, may be unsuitable for your indoor setting. Indeterminate tomatoes also need a more extensive trellis system for support; plants take longer to grow and their tomatoes take longer to ripen. On the other hand, if you have the space and are willing to accommodate your tomato plants’ needs, you can attempt to grow any types that suit your taste buds. 

Best Types of Tomatoes to Grow Indoors

If your window space or indoor garden area is more compact, you’ll want to stick to the best types of tomatoes to grow indoors such as dwarf tomatoes. Small fruited tomato plants are ideal for indoor settings. Plus, these tomato plants mature more quickly. Experienced indoor tomato gardeners recommend cultivars such as Pixie, Tiny Tim, Florida Petite, and Mountain Spring tomatoes. Determinate tomatoes grow with a bush-like growth habit as opposed to vining; this makes them easier to maintain and care for inside your home. 

Growing Tomatoes Indoors: Supplies

To grow tomatoes indoors, you’ll need the following supplies for best results:

  • Seed starter mix (starting mix should be sterile and soilless potting mix)
  • Seed tray
  • Artificial light (i.e. LED grow light)
  • Heat mat (optional depending on your climate, but ideal for germination)
  • A large pot with drainage holes (good drainage is essential for tomato plants)
  • Water
  • Fertilizer
  • Plant stakes

Sow Your Tomato Seeds

Add a layer of dampened soilless potting mix to your starting trays. Create ¼-inch deep holes in the soil and place two or three tomato seeds in each hole. Place your tray on a heat mat or in a window; heat is the key element for getting tomato seeds to germinate. After your tomato seeds germinate, you should be able to transfer your tomato seedlings to a larger pot with good drainage in about a month. You can use the same potting mix as you used for your seed trays when replanting your young tomato plants. Be sure to take extra care with their roots when repotting your plants.

How to Care for Indoors Tomato Plants

After you transplant your tomato seedlings, be sure to water them every few days–more often if the soil becomes dry. Once they’ve settled into their new container, follow these care and maintenance tips:

Light

Tomatoes need sun and plenty of it. They need at least 6 hours of direct sunlight. Turn your tomato plants around in the wind every few days so that all parts of the plant get optimum sun exposure. For growing tomato plants indoors, you may also need to rely on artificial light to ensure your plants get the amount of daily light they need to thrive and produce delicious tomatoes.

Temperature

Tomatoes like it hot. If the window you place them near is drafty during the cold seasons, your tomatoes will not be pleased. You may want to use a heat pad during the winter months. When growing indoor tomatoes, try to house them in an area that is between 75-80 degrees Fahrenheit.

Water

Water your tomatoes so that the soil is moist but not soggy. As soon as you notice that the soil is dry, be sure to water your tomato plants. Tomatoes are hungry feeders. 

Fertilizer

After moving your tomato seedlings to a large pot, fertilize them every two weeks. Once green tomatoes begin to grow, you can fertilize them weekly. A slow-release fertilizer works best for growing indoor tomatoes.

Finally, as your indoor tomato plant vines grow, you will need to add garden stakes to your pots. Tomato plants can use the stakes for support as they climb. You can encourage your tomato plants to grow vertically by using some twine to tie the plant to the garden stake. You can also use a tomato cage to help tomatoes grow upwards.

Do I Need to Pollinate Indoor Tomatoes?

When growing tomatoes outdoors, you typically do need to pollinate. In fact, tomatoes are self-pollinating. However, humidity and poor air circulation can negatively affect pollination. When growing tomatoes indoors, you can perform pollination by hand since there is no wind or insects around to help with the job. You can encourage pollination by shaking the tomato stems each day; this simple act should help spread pollen.

How to Harvest Indoor Tomatoes

Plan to harvest tomatoes before they are ripe in order to reduce the risk of cracking. They should still appear green or appear half ripe. To harvest, hold a tomato near its stem and twist it off of the vine. Then, place your harvested tomatoes on the kitchen counter where they can ripen fully within a couple days. 

How to Store Tomatoes

Once your tomatoes are ripe, you can store them in your refrigerator in a plastic container. Ideally, you should allow your tomatoes to come to room temperature again once you plan to eat them; they’ll be juicier that way. Keep in mind that some tomatoes tolerate refrigeration better than others in terms of taste. Cherry tomatoes tend to do well in the fridge. If possible, try to eat your stored tomatoes as soon as possible so that they’ll be as delicious as you’d hope. If you harvest lots of tomatoes, you can also freeze them or turn them into sauce and freeze them. Goes perfectly with fresh indoor basil, too!

Indoor Tomato Plants FAQs

Can a Tomato Plant Grow Indoors

Yes, you can grow tomatoes indoors provided that you attend to their needs such as sunlight, warmth, and other care needs.

Can I grow tomatoes indoors all year round?

Yes, you can grow tomatoes indoors all year round. Keep in mind that large fruit producing tomato plants will take longer to mature. Dwarf cultivars are the easiest to grow tomatoes indoors.

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