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How to Grow Tomatoes Indoors From Seeds

By Elton Dunn ; Updated September 21, 2017
Good planning helps ensure a bountiful tomato crop.

Tomatoes are a staple of the summertime garden, and they can be easily grown from seed, even for beginner gardeners. Growing tomatoes from seed does take planning, so gardeners should begin six to eight weeks before the final frost in their area. After the initial growing period, tomatoes must be moved outdoors to maximize sunlight.

Fill the chambers of your seed-starting tray with seed-starting material, which is enriched to support seeds. Avoid using standard potting soil.

Poke two holes in each seed chamber, using a pencil. Make the holes 1/4 inch deep.

Drop one tomato seed in each hole. Cover the hole with soil to bury the seed.

Water the soil until it becomes saturated. If the seed tray has a cover, slide it on. This promotes warmth and humidity. If your seed tray has no cover, wrap it with plastic wrap to promote humidity.

Place the seed tray in a secure place and wait for the tomato seeds to germinate, which should take one week. Monitor the water level and moisten the soil whenever it seems dry.

Move the seed tray underneath a clamp light when the tomato seeds germinate. If you don't have a clamp light, place the seed tray in a south-facing window where it receives maximum sunlight. The seeds need as much light as possible to grow.

Water the seedlings when the soil is dry to the touch. Turn the seed tray 180 degrees each day so all seeds receive light. Continue to water the seeds until you notice two to three sets of leaves.

Fill 4-inch pots with potting soil, then poke one hole in each pot with a pencil.

Grasp one seedling at its base with two fingers. With your other hand, stick a fork in the seed chamber and push the plant up and out. The seedling's roots will come free. Place a seedling in the pot so its stem is buried and only the leaves remain above ground. Cover over the seedling with soil. Plant all seedlings in this manner. Place the 4-inch pots back in the window sill.

Water the plants when the soil dries out and rotate them in the window sill (or under the light) until both daytime and nighttime temperatures are 55 degrees Fahrenheit or higher in your area.

Bring the seedlings outside for a few hours each day. Place the pots outdoors in the sun for two to three hours per day, then increase this time over one to two weeks until the plants are outside all day. Once your plants are outside all day, they are ready for planting outside.


Things You Will Need

  • Seed-starting tray
  • Seed-starting material
  • Pencil
  • Water
  • Clamp light (optional)
  • 4-inch pots
  • Potting soil
  • Fork

About the Author


A successful website writer since 1998, Elton Dunn has demonstrated experience with technology, information retrieval, usability and user experience, social media, cloud computing, and small business needs. Dunn holds a degree from UCSF and formerly worked as professional chef. Dunn has ghostwritten thousands of blog posts, newsletter articles, website copy, press releases and product descriptions. He specializes in developing informational articles on topics including food, nutrition, fitness, health and pets.