
How to Grow Tomatoes Indoors for Vine-Ripened Fruit Year-Round, According to
Do you love to grow tomatoes? You’re not alone: Tomatoes are a mainstay in many gardeners’ plots—including Martha’s. According to Martha, this bold, red fruit delivers the taste of summer with every bite. “And, they’re filled with excellent antioxidants and vitamins,” she says.
Since tomatoes are known to grow best during warmer seasons, you might wonder if you can also grow tomatoes inside your home. Well, good news: You can. Ahead, experts share everything you need to know about growing tomatoes indoors.
- Rebecca Sears is the chief gardening guru for Ferry-Morse, a seed supplier company.
- Levi Gardner is a professor of environmental studies at Grand Valley State University and co-executive director of Urban Roots, a non-profit community farm and education center in Grand Rapids, Mich
How to Grow Tomatoes Indoors
If you love this delicious fruit and want to produce your own—no matter the time of year—there are just a few things to remember when growing indoors. “You will need to mimic the ideal outdoor conditions for the tomato to grow tomatoes successfully and produce fruit,” says Rebecca Sears, the chief gardening guru for Ferry-Morse. “That includes ample space for the root ball to grow, staking to keep the plant upright, good airflow and pruning, regular watering and feeding, and full sun.”
Selection and Planting
Sears says that the tomato seed variety you plant will make a big difference in how it will thrive in your home. She suggests a natural, disease-resistant variety, like Better Boy Hybrid and Big Boy Hybrid, as they reap deep red tomatoes from seed.
Here are some tips for successful indoor planting:
- Plant the natural, disease-resistant seeds in soil that provides adequate drainage. If you are short on space or large containers, Sears says you should choose a determinate or a patio variety.
- Water the plant regularly (as much as needed to keep the soil moist, but not wet).
Fertilizing
When planting your tomato plant, be sure to mix in some organic slow-release fertilizer into the soil for the ideal growing environment. Then, once your tomato plant begins to sprout, you’ll need to begin regularly fertilizing it. To do this, add a balanced organic fertilizer to the soil or use a water-soluble plant food once per week.
Light
“Tomato plants require full sun to grow properly and should be maintained at a temperature around 70 to 75 degrees,” says Sears. If your home doesn’t get the best direct sunlight, you will need to use a grow light on the tomato plants for 16 to 18 hours a day to ensure they receive enough “sun” indoors. Otherwise, tomatoes will need eight to 10 hours of direct natural sunlight each day from inside the home.
Pollination
In order for the plants to grow fruit, they will also need pollination. “Without bees and wind to do the job, you’ll need to help the process along by either using a small paintbrush to transfer pollen from flower to flower or using an oscillating fan to encourage the pollen to travel,”
Staking for Stability
Tomato plants that are grown indoors can often have more fragile stems than outdoor plants. To help strengthen your tomato plant, you’ll want to add a three-foot stake to the container you’re planting it in. As it continues to grow, tie the stem to the stake using twine for additional support.
Pruning
“Prune any side shoots between the main stem and side stems to redirect the energy to tomato production and to keep the plant from overgrowing your space,” says Sears. Pruning will also help lead to bigger fruit, as new shoots can produce flowers instead (this causes stems to grow without tomatoes), says Levi Gardner, a professor at Grand Valley State University and co-executive director of Urban Roots.
Harvesting Tomatoes Indoors
Sears says that the color of the tomato itself will help you decide when it’s time to harvest. And similar to tomatoes grown outdoors, tomatoes grown indoors should be harvested when they are completely ripe—this will result in the best flavor.
When most tomato varieties turn from green to red and start to soften slightly to the touch, they are ready to harvest. You can check the ripeness of the tomatoes further by giving them a light squeeze to test their firmness (the firmer the better). Once the tomato’s ripeness is to your liking, Sears says to hold the stem of the plant with one hand and pull the tomato off with the other.