Easy steps to grow your own tomatoes from seeds

Planting tomatoes from seed has some advantages. There is a larger selection of varieties, seeds are considerably less expensive than plants and it is very rewarding to nurture plants from seed to harvest.

Varieties

Do you want to eat them fresh as a snack, on grilled hamburgers or in salads? Would you rather use them in your favorite recipe for spaghetti sauce? Choose slicing, cherry or paste tomato varieties.

Do you have enough room for indeterminate varieties, vining types that grow 6 feet or even taller? If space is an issue or plants will grow in containers, select determinate varieties. These grow to a height determined by their genetics and stop, generally around 3 feet.

There are a number of diseases that affect tomatoes. Seed packets indicate disease-resistance with initials like F for fusarium, TMV for tomato mosaic virus and V for verticillium wilt.

Containers

Tomatoes don't care what kind of container they grow in as long as they have drainage holes. Anything from egg cartons to recycled yogurt cups can be called into service - just poke holes in the bottoms. Save small pots when planting annuals in the spring. Wash them with a solution of water and bleach at a ratio of 10 to 1 before use.

Of course, seed starting pots can be purchased. Pots at least 3 to 4 inches wide have enough room for roots to grow without getting pot-bound.

Soil

Fill containers with seed-starting or light soilless potting mix. Young roots easily grow through a mix that is light and fluffy. Peat-based products retain water, keeping seeds moist while germinating.

Planting

Determine the correct time to plant by counting back eight weeks from the last frost date. In our area, depending on the source you consult, the average last frost date is in mid-May. If started too soon, plants may outgrow their pots.

Moisten the potting mix before filling containers, leaving a half inch at the top. Put two or three seeds in each pot. Extra seeds will ensure at least one strong plant per pot. Barely cover seeds with one-quarter inch of additional potting mix and gently firm. Water the seeds with a spray bottle.

Germination

Tomato seeds germinate best at room temperature, but you can encourage faster germination by setting pots on a heating pad set on low. Mist seeds to keep them moist until they sprout. Germination typically occurs in a week or so.

Containers can be covered with plastic wrap, the greenhouse top of a seed-starting kit, or put in a plastic bag to increase humidity. As soon as seedlings sprout, remove the covering and move them under grow lights or to a sunny window.

Care of plants

Seedlings need a lot of light - 12 hours minimum - for best growth. Even the sunniest window may have difficulty providing enough light. Supplemental lights should be placed just 6 inches above seedlings so they don't stretch to reach light. Move the lights up as plants grow. If plants are grown near a window, be sure to turn them every day so they don't lean toward the light.

Water seedlings to keep the soil moist but not soggy. Once they have their second set of true leaves, begin fertilizing with a water-soluble fertilizer at half-strength every two to three weeks.

A small fan blowing across seedlings will provide good air circulation, reducing the risk of disease and strengthening stems. If you don't have a fan, rub your hand across the tops of plants several times a day.

If plants get too large for their containers, repot to larger pots. Being pot-bound stunts their growth.

Hardening off

As the last frost date draws near, begin acclimating plants to the outside gradually. Start with a couple hours in a shaded, protected site and slowly increase their exposure to conditions.

• Diana Stoll is a horticulturist and the garden center manager at The Planter's Palette, 28W571 Roosevelt Road, Winfield. She blogs at gardenwithdiana.com.