Did you ignore my warnings to wait to plant the warm-season garden until mid-to late April? If you did, and your plants were damaged by the temperatures below freezing, it’s not too late. In fact, you are right on time.
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 please monitor the long-range forecast. I have been covering my tomatoes these past few days when temperatures dipped back into the low 40s (after having been 92…poor plants!)
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 have been taken care of (and not left out on the sidewalk outside a big-box store when the temperatures are too cold for them). You can also purchase plants from garden centers like Grow Your Garden with Sal. 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 mature 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 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.