Q: How do I start tomato seedlings indoors?
A: To grow your own tomatoes for transplanting outdoors, sow the seeds indoors four to six weeks before the usual last frost (around May 15 in the Chicago area).
Use a sterile seed starting mix and any containers that will hold soil, provide drainage, and accommodate growing roots. Moisten the soil, place two seeds in the pot, and cover lightly with more soil mix. Cover the pots with clear plastic to keep the soil evenly moist and place the plants in a warm location until germination occurs.
When seedlings emerge, remove the plastic and place it near a sunny window. After the seedlings develop their first set of true leaves, pinch the weaker plants down to soil level. Water the seedlings when the soil is dry.
It is important to slowly acclimate tomato plants to outdoor temperatures, wind, and the sun’s ultraviolet rays before planting them in their permanent location. This process, called “hardening off,” helps ensure that plants get a good start. After all danger of frost has passed, plants should be moved to a shady area of the garden for several hours each day. Gradually increase the time the plants are exposed to outdoor conditions. This may entail moving them in and out for a period of three to seven days. After the tomatoes have been planted, be prepared to cover them if the temperature drops below 50 degrees Fahrenheit.