It’s the beginning of May, so it’s time for my annual appeal to hold off on planting out your tomatoes and other cold-sensitive crops. I think the plea may fall on deaf ears this year, because looking ahead at the 10-day forecast here in upper Montgomery County, I see only one night that might fall below 50 degrees F., and only barely below. Days are nice and warm. It feels like tomato-planting time.
Let’s just state a few caveats, though, and then I’ll let you go about your business.
- In many recent years, we’ve had a substantial drop in temperature in mid-May, even after summerlike conditions had already taken hold. That may not happen this year, but it still could.
- It looks like we are finally going to get some rain coming up—hurray!! We really need it. But a rainy period isn’t the best time to put tomatoes in the ground, not because you get wet, but because the plants do. Wet leaves and splashing mud will make them more susceptible to fungal diseases that could be lurking in the soil. If you do plant during or before a lot of rain, make sure the soil is covered by mulch.
- Most importantly, the air temperature at planting time matters less than the soil temperature, and at least where I’m measuring, the soil temperature is far below the ideal 60 degrees F. that tomatoes prefer. Get yourself a soil/compost thermometer and stick it in the ground where you intend to plant; see for yourself. Cold soil temperatures hold back the growth of plants that like it warm, and fruit may be poorly formed.
My tomato and pepper plants are still inside under lights. They’ll venture outside to start hardening off this weekend, so that in another week or so, if the forecast looks good, I’ll be able to consider putting them in the ground. But I’m definitely going to check that forecast and stick that thermometer in the soil.
If you’re in a hurry, and are ready to jump in and protect your plants if we have a mid-May frost, I can’t stop you from planting. You may end up with plants that produce much earlier than mine. Or they may sulk and get diseases and make misshapen fruit. Sometimes the bet pays off, and sometimes it doesn’t. I like to play it safe.
By Erica Smith, Montgomery County Master Gardener. Read more posts by Erica.
