Growing Tomatoes from Seed

Baby Tomato

Ah, the anticipation!

Lori Dunn

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Growing tomatoes from seed is much easier than it might seem.

And, after a winter spent perusing the seed catalogues – recommended catalogues include Totally Tomatoes, Baker Creek Heirloom Seeds and Territorial Seed Company for open-pollinated tomatoes – it’s more fun to plant the crazy varieties you’ll find there instead of the same old stuff you’ll find at the big run-of-the-mill nursery.

Starting your own plants from seed, you can grow tomatoes that are orange, yellow, striped, green, white, pink, purple, nearly black and – yes – even red.

Start them indoors about six to eight weeks before your last frost. Baby tomato seedlings are very susceptible to a fungus called “damping off,” which kills seedlings, so use a sterile seed-starting potting soil. The seeds require a good deal of heat to germinate – ideal temperature is 70 to 80 degrees. A sunny window might do fine, but to germinate very quickly, put your seed tray or pots on a heating mat (yes, the kind you can buy at the drug store) turned onto its low setting. This will hold your soil at a consistent temperature.

Be sure to keep the soil moist. Some tomato seeds will sprout in just two or three days, and they will keep sprouting up to 10 days. Don’t let the soil temperatures go much over 90 degrees or you’ll cook the seed instead of sprout it.

Once the tomatoes sprout, watch the plants for their first set of “true leaves” – leaves other than the matching pair (called seed leaves or more correctly cotyledons) that come out as they sprout. You can now transplant them into bigger pots. Because you transplant so quickly, you can plant tomato seeds very close together in their initial container.

Once transplanted, spritz the plants with dilute fertilizer. Liquid kelp, in particular, is nice for young tomato plants.

Make sure your tomato seedlings get plenty of light – tomatoes that get too little light get very long stems (they get “leggy”), which is not good for the plants. Putting them outside on warm days can be a good idea, as this also exposes them to a bit of wind and makes their stems stronger. Just be sure to bring them back inside to a warm place at night.

As the plants grow, repot them in larger containers to make sure their roots have room to expand.

Once the last frost date has passed for your area, plant your tomatoes in the garden. Here’s a fun tomato tip: Tomato plants will grow roots along their stem if you plant them deep. This helps anchor the plant and keep it from toppling over when it gets heavy with fruit.