By JOYCE KARSNAK
OSU Ext. master gardener volunteer
Last May while browsing in a local garden center, I spotted a couple I knew pushing a big cart loaded with beautiful flowering plants — the instant gratification kind. Turns out, this was their second visit to the greenhouse, this time to replace all the plants they bought the week before. Everything had frozen on their deck, even though they had covered them. “Well, maybe if you prune them back a little, some will make it,” I said. They shook their heads, “Nope, dead.”
What went wrong?
First, their plants went straight from the greenhouse onto the deck. The deck has no protection from the sun, wind, and in this case, a late spring freeze. Second, they thought protecting them with a cover was enough, but when the temperature dips too low or the wind is strong, young plants are susceptible to damage. A controlled greenhouse climate pampers the young plants to get them to grow big and strong. If planted in the heat of summer they may be fine. But when you put them directly out into Northeast Ohio’s spring weather, you may be headed for trouble.
When you bring your annual flowers and vegetable transplants home, restrain your enthusiasm to head into the yard to plant. Plants that were started indoors or purchased from greenhouses need to be acclimated — “hardened” — to the outdoors. Start by placing the plants in a protected shady spot. Then gradually expose the plants to longer periods of direct sun. I move mine out into the morning sun, but only if it’s not too windy.
Be sure not to let them dry out. Move them into a garage if the weather turns stormy and most definitely if an overnight frost threatens. Transplants should be ready to plant after about a week of hardening.
A cool, cloudy day or after the strong sun’s rays have passed for the day is the best time to plant. This gives the plants a bit of time to recover before being exposed to the strong midday sun. If you feel wilted planting in the hot sun, your plants do, too.
Giving your newly purchased plants care before you put them out will get them off to a good start.
For more on how to select transplants and when to plant them, check out go.osu.edu/harden.