How to Start Tomato Plants Inside


Tomatoes, once grown only for ornamental purposes, are now available in hundreds of hybrid and heirloom varieties. Whether you choose hearty beefsteaks, snack-size grapes or saucy romas, the superior taste of homegrown tomatoes enhances everything from sauces to salads. Determinate varieties will ripen in a month's time and do not require staking or support, while indeterminate tomatoes keep growing throughout the season and produce fruit until the first frost. Tomatoes thrive in a number of conditions and succeed in the garden, containers and even hanging baskets.

Step 1

Start tomato seedlings indoors at least 6 to 8 weeks before the last expected frost date for your location. Germination can take up to 10 days and tomato plants should be at least 8 inches tall before moving to a permanent location.

Step 2

Place potting mix in a bucket or large bowl and add water, by the cup. Stir until soil is moistened but not saturated. Fill peat pots or seed flat to the top with moistened potting mix.

Step 3

Use a straw or pencil to poke one or two 1/4-inch holes in each container or each section of a seed tray. Insert one seed into each hole, then cover lightly with soil.

Step 4

Water each container or seed tray lightly, then cover loosely with plastic wrap. Place the pots or trays in a warm, sunny location with lots of sunlight or use growing lamps to maintain a temperature of 75 to 85 degrees. Keep soil moist, but not saturated, during the germination process. Once the seeds have sprouted, remove plastic wrap and keep temperatures between 60 and 70 degrees to sustain proper growth.

Step 5

Transplant seedlings into larger containers when they have developed at least two sets of true leaves. True leaves are the second set of leaves developed after the seed sprouts. This will allow the plants to develop a stronger root system needed for successful transplanting.

Step 6

Keep soil moist but not saturated during the indoor growing process. Avoid heavy watering from above, as this can uproot the seedlings. Use a larger seed flat to hold individual pots and add water to the tray instead of each pot.

Tips and Warnings

  • Avoid fertilizers with a high ratio of nitrogen. Too much nitrogen will result in heavy foliage and little fruit.

Things You'll Need

  • Tomato seeds
  • Seed starter potting mix
  • Peat pots or sectioned seed tray
  • Water
  • Water-soluble fertilizer/plant food
  • Plastic wrap
  • Straws
  • Growing lights


  • Victory Seeds: Growing Tomatoes from Seed
  • University of Illinois Extension-Watch Your Garden Grow: Tomato

Who Can Help

  • Horticulture Guy's Garden Supply: Sectioned Coir Fiber Seed Trays
  • Victory Seeds: Average First and Last Frost Dates by State
  • Tomato Varieties
Keywords: starting tomatoes from seed, germination process, transplanting tomatoes

About this Author

Deborah Waltenburg has been a freelance writer since 2002. In addition to her work for Demand Studios, Waltenburg has written for websites such as Freelance Writerville and Constant Content, and has worked as a ghostwriter for travel/tourism websites and numerous financial/debt reduction blogs.