Seed catalogs are brimming with varieties of tomatoes—exponentially more than you'll find as seedlings in the spring. Growing tomatoes from seed requires a bit more work but with minimal investment, you'll have healthy, stocky seedlings ready to transplant on Memorial Day.
You will also need a warm location for germination and a bright location for the seedlings, plus the following equipment: seeds, water, soluble fertilizer, containers for the seeds, a tray for the containers, cover for the containers and labels. A purchased sterile potting mix is optimal for seed starting. It is lightweight and decreases the incidence of disease. Do not use garden soil to start tomatoes.
Containers should be about two-inches deep and have adequate drainage. You can repurpose yogurt cups or take-out containers provided that you create holes in the bottom for drainage. Reduce the chance for disease by sterilizing containers. Soak for ten minutes in a bleach solution of one-part bleach to ten-parts water and allow to dry thoroughly. Cell packs are the way I usually go. They come in many sizes and fit snuggly into trays which come with raised clear plastic lids. Being frugal, I often reuse the cell packs from year to year, sterilizing them after use. Peat pots and expandable peat pellets allow for the planting of seedlings directly into the garden soil.
The seed packet contains critical information, including when to start the seeds indoors and when to transplant outdoors. If started too early, seedlings become weak and leggy. Note the depth of planting (¼ inch for tomatoes), temperature for germination (75 to 85°F) and the days to germinate (seven to ten). Seed packets will detail days to harvest, the time between planting outdoors and your first ripe tomato, as well as suggested spacing in the garden. Most tomatoes require two to three-feet depending on cultivar and staking method. All tomatoes require full sun, at least six hours a day.
Begin the planting process by dampening the soilless potting mix. Fill the containers and gently tamp down. Place seeds in the mix, cover with ¼ inch of the dampened potting mix and water gently. I generally plant two seeds in each container. If both emerge, I eliminate the weakest one by cutting it off at the soil line. Label your tomato cultivar. You can purchase labels or repurpose plastic utensil handles, aluminum blinds, cut up plastic milk jugs or popsicle sticks.
Place the containers in a tray and cover to retain moisture. If you aren't using the lids that come with seed flats, plastic wrap can be used or the whole tray can be placed in a clear plastic bag. The labels will keep the plastic above the soil allowing space for the seedlings to emerge unharmed.
Place your trays in a warm location. Tomatoes germinate best at 75 to 85°F. I place trays on my covered radiators and have great success. Others use the top of the refrigerator. You can purchase a germination mat for this specific purpose.
Cotyledons, or seed leaves, should sprout in a week or so. Once they have emerged, uncover the trays and place them in a warm spot (70°F) under very bright light. A south- or west-facing window can work in a pinch, but fluorescent shop lights allow for steady light and sturdy plants. My lights are suspended with adjustable chains above a table from the joists in my basem*nt. The lights, containing two cool bulbs, are adjusted for the next several weeks to be consistently two to four inches above the seedlings and are kept on via timer 14 to 16 hours a day.
As they grow, keep the seedlings consistently moist. Feed them with half-strength soluble fertilizer every two weeks.
A week or so before planting out, your stocky seedlings will need to be gradually acclimated from their coddled existence to the harshness of the outdoors. Reduce water, place first in warm shady spot and eventually transition to full sun.
Seeds for tomatoes are viable, on average, for five years. The number of seeds in the packet varies but is always more than I can possibly grow in that time. Extra seeds can be stored from year to year in an airtight container in a cool dry place.
Gather those seed catalogs or go online, spend the coming weeks choosing from the dizzying array of tomato choices and discover new favorites to enjoy this season.
