A short post today, in which I make my annual plea to hold off on planting summer vegetables until it’s warm enough. Please – your garden will thank you later!
We have some guidelines on the HGIC website about when to plant vegetables and how to harden them off (get them used to outdoor conditions). Remember, though, that planting isn’t about dates; it’s about temperature. It is not a hard-and-fast rule that your tomatoes should be in the ground by Mother’s Day. What if it’s 40 degrees on Mother’s Day? Bad for outdoor brunch, but also bad for young tomato seedlings.
In general, vegetables that prefer summer’s heat also don’t like spring’s cold. Tomatoes, peppers, squash, cucumbers, and all their friends want soil temperatures over 60F and air temperatures over 50F (including at night). Try to wait to put them in the ground until the forecast shows at least a week of these conditions, with no cold snaps or heat blasts. Of course, spring is full of crazy ups-and-downs (especially this spring) but if you can give the plants a good start, they will tolerate temperature swings better. If a frost is predicted, or really anything below about 45, throw some kind of covering over the plants: heavy-duty row cover if you have it, but a sheet or light blanket will do.
Get to know your garden’s microclimate – if it’s protected from strong winds, plants will tolerate cold better; if it gets a bit of afternoon shade, they will get through high heat with less damage.
You can purchase all kinds of devices to give your plants extra protection, but after trying them all I found I preferred just having some patience. If you do use them, make sure they’re easy to put up and take down – struggling with a complicated shelter in wind and rain is no fun, nor is removing the whole thing again when it’s 85 the day after dropping to 39.
I know, all my plants are huge too, and really want to go outside. But I’m going to wait until it’s time.
By Erica Smith, Montgomery County Master Gardener. Read more posts by Erica.
I believe that the subject deserves to include the benefit of going through the effort to putting them out during warm days then bringing in at night to protect from cold. This helps the hardening off which includes sun and wind tolerance, and reduces leggy growth. While it is a hassle, so is much of what is involved which successful gardening.
Well, yes, that’s why I put the link to the HGIC page on hardening off, but absolutely. Worth the effort.
Great advice Erica. Tomatoes planted last week in Howard County are showing signs of cold damage. Raised beds will warm a little faster than the surrounding ground, but using a thermometer always works.