It’s not too late. In fact, you are right on time because the low temperature this morning in Blythewood was 39 degrees.
Visiting big box garden centers in the early spring makes me a little sad. It’s mid-March and at least two weeks before our historic last frost, but outside the store sit beautiful tomato plants that have just come out of a greenhouse. Temperatures into the 40s and even high 30s are predicted this week. Shoppers might naturally assume that if the store sells the plants, it must be time to set them into the garden.
However, tomatoes, peppers, squash, and other typical summer crops do not like cold weather. And it’s not just temperatures below freezing that are the problem; temperatures below 50 degrees stunt their growth even if the damage is invisible. April 15 is usually a safe date to set out warm-season plants without protection but monitor the forecast.
I start most of my plants from seed so I can grow exactly what I want to grow and so I can make sure they are safe. Seeds need heat and moisture to germinate, and they need appropriate temperatures, light, and consistent water to thrive.
I start my plants inside the house on heat mats. Heat mats, which are vinyl-coated mats designed to raise the temperature of the soil placed upon it 10-15 degrees above the ambient air temperature, trick the seeds to germinate indoors quickly and evenly.
Take the seedlings off the heat mat and put them under grow lights as soon as they begin to sprout. Grow lights give seedlings the complete UV spectrum of light to encourage the plants to grow into short, stocky, dark green seedlings—not the pale spindly ones you might have grown on a windowsill or under household lights.
Most seedling troubles come from over or under watering. Before the seeds germinate, keep the soil moist, but not sopping wet, all the time. On a heat mat most seeds germinate within a few days. After the seeds germinate, water when the soil feels a bit dry to the touch but before the plants visibly wilt. It’s best to water at about the same time every day. Plants that are healthy and growing rapidly should need water every 24 hours. “Damping off” occurs when previously healthy seedlings topple over and die. This occurs when seedlings live in cool conditions and are kept too moist.
Don’t give up when you kill trays of seedlings. I have started tens of thousands of seedlings, and I have killed thousands. I killed a tray of seedlings just this week when I missed watering it. I have succeeded at growing things because I just kept trying. Killing plants is just part of gardening. Buy extra seed so you can start over. We have a long growing season and plenty of time.
