Plan the perfect garden with our interactive tool →

How to Grow Tomatoes Indoors

tomatoes image by Marius Lazin from

The flavor of a vine-ripened tomato midwinter makes all the work to grow them worthwhile. Dedicate a sunny window for planting successive tomato crops indoors to keep the harvest coming year-round. Grow patio or dwarf tomato plants in large containers and supplement the light with fluorescent bulbs as needed. Maintain the temperature between 65 and 75 degrees for ideal growth.

Plant tomatoes in a 12-inch or larger pot with good drainage. Place a piece of screen in the bottom to hold in the soil and fill the pot 3/4 with a mixture of equal parts potting soil, peat moss, perlite and organic compost. Mix in a slow-release tomato-formula fertilizer.

Look for healthy, compact tomato plants with a strong trunk and well-developed roots. Small determinant varieties do best for indoor growing. Plant the tomato approximately one inch deeper than it originally grew. Firm the soil around it and give water until water comes out the hole in the bottom.

Place the container in a sunny window. Supplement the light if needed with a grow light or a compact fluorescent light in a shoplight fixture. Adjust the light so that it is four to six inches from the leaves. Warm the bulb, then place your hand at leaf height to make sure it is not too hot.

Leave the grow light on for 16 hours per day when the plants are young. Decrease the light to 12 hours per day to trigger flowering.

Check the soil moisture daily and water as needed to keep the soil moist, but not wet.

Turn the plant every other day to maintain even growth. The plant will naturally turn toward the light. Adjust the light height as the plants grow, keeping it four to six inches above the top of the plant.

Use a fan or air-conditioner as needed to maintain the temperature when using many lights.

Hand-pollinate the flowers by shaking the flower stems every other day.

Fertilize with a water-soluble tomato formula every two weeks, beginning when the fruits begin to appear.

Allow the tomatoes to ripen on the vine. Pick when fully ripe.


Plants that are tall or leggy need more light. Supplement the light with more fixtures or use reflectors to focus light on the plants.

Garden Guides