How To Grow Tomatoes Indoors - Backyard Boss
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How To Grow Tomatoes Indoors

Tomatoes are a staple in any vegetable garden, and its no secret that the vibrant fruits are delicious in an abundance of summer dishes. They are easy to grow outdoors in the summer months, whether you add them to your garden or grow them in pots. The warmth of the sun and plenty of water are generally all the fruits need to remain happy and healthy.

But once things get a little cooler, or if you have an overflowing vegetable garden, you may want to bring your tomato plants indoors. With that said, caring for these plants inside is a little different and they will require more attention than if they were outside. Learn all about the tools you’ll need and the steps you need to take to grow tomatoes indoors.

Tools You’ll Need

Tomato seedlings in a plastic cup
Image credits: JulijaDmitrijeva via Shutterstock

Ready to begin growing your tomatoes indoors? First, you’ll need to gather a few tools. 

  • Tomato plant seedlings or seeds
  • Pot with drainage
  • High-quality, well-draining potting mix
  • Compost
  • Seed starting soil mix
  • Fertilizer
  • Hand trowel
  • Gardening gloves
  • Tomato cage
  • Watering can or hose

How To Grow Tomatoes Indoors

With the proper tools in hand, it is time to get growing your tomatoes indoors!


Hand picked homegrown organic cherry tomatoes, tomatoes in pots, grow bag, grow your own vegetables in a pot at home, greenhouse
Image credits: Sireli via Shutterstock

The first step in growing tomatoes indoors is choosing the right variety. Since you’re likely limited on space, you’ll need to choose determinate (bushy) varieties over indeterminate (vining). Varieties such as Small Fry, Pixie, and dwarf varieties generally work best in containers around 6-inches. If you choose a larger variety, you will likely need a 3 gallon container.

Pro Tip: If you plant an indeterminate variety, install a tomato cage to help contain and guide the growth. This also supports the heavy fruits so they won’t fall off the vine.

Germinating Seeds

Cherry Tomato seedling, close up. Macro of Red Robin Cherry Tomate plants just emerged on window sill or in greenhouse, 1 week after planting tomato seeds. Early spring planting. Selective focus.
Image credits: sophiecatvia Shutterstock

If you want to get a jump on the growing season, or simply grow your tomatoes to maturity indoors, it is very simple to germinate tomato seeds inside. For a jump on the season, start sowing seeds in mid-March to early April. If you’re growing inside, germinate seeds any time of year.

Fill 2-inch pots with damp seed starting soil and plant two to three seeds together roughly an inch deep. Keep them in a warm, sunny location and they should sprout in about two weeks. You can then transplant them into a larger pot. If you’d prefer, you can simply plant seedlings from the store instead! You can grow fruit faster this way.

Potting and Potting Media

Tomato seedling, pots, and soil
Image credits: neelam279 via Pixabay

Tomatoes do best in a well-draining potting mix to ensure they don’t suffer from overwatering or waterlogged soil. Choose a pot with drainage holes and opt for materials that are well-draining, such as terracotta. Fill the pot about a third full with soil, add your plant, and top with more soil.

Pro Tip: Mix fertilizer or compost into the soil since tomatoes are heavy feeders to improve your tomato harvest. You can use crushed eggshells to add calcium or coffee grounds to increase the acidity of the soil.

Watering and Fertilizing

A woman waters dwarf cherry tomatoes in a pot on the windowsill on the balcony in the apartment. Organic eco-friendly vegetables and greens grown at home
Image credits: OMfotovideocontent via Shutterstock

Tomato plants tend to struggle when under-watered, so keep track of your watering routine. Consider how fast draining the soil is and use your finger to test the moisture levels every day. Once the soil is dry about an inch deep, it is time to water the plants. Water until it drips out of the drainage hole, but remember to empty the drainage tray so the plant isn’t sitting in stagnant water.

Since tomatoes need so many nutrients, fertilizer is essential. Fertilize weekly, beginning two weeks after you transplant the seedling. Use a liquid fertilizer at the same time you water, ensuring the plant gets a big drink and plenty of food! Avoid over-fertilizing the plants by testing the soil pH first–it should be around 6.2 to 6.8.

Light and Placement

Small bush of balcony cherry tomatos in brown pots on white windowsill. Gardening tomatoes in the home at summer
Image credits: Sunny_Smile via Shutterstock

If you want to grow tomato plants indoors, it is best to recreate similar conditions to outdoors in the summer. Choose a bright, sunny spot that stays warm. Keep the tomatoes away from drafts and chilly windows. Tomatoes need direct sunlight all day, but if you can’t provide this, supplement with around 16 hours of grow lights, positioned 4 inches away from the plant, each day.

Pro Tip: Gently shake the tomato plant every so often. Since there aren’t any pollinators indoors, you’ll need to help the flowers release pollen, which lands on the plant’s stigma for fertilization, manually! Once fertilized, the plant can begin producing fruits.

Get Growing!

Though they require a little extra time and attention, tomatoes are still relatively easy to grow indoors. With the right tools and a little patience, you’ll enjoy a few scrumptious fruits in no time. Keep them warm, well-watered, and in enough light each day to help them thrive.

Do you have any tips for growing tomatoes indoors? Share in the comments below!