Seedlings benefit from an opportunity to harden off before being transplanted.
On Good Friday, at the beginning of last month, I planted a few hundred vegetable and flower seedlings in black, plastic trays. They’ve been happily stretching upward under grow lights ever since.
In previous years, I’ve always bought vegetable plants to grow in the garden rather than bother with tiny seeds. This year, in the perpetual hunt for novelty, I decided I’d attempt to grow nearly everything from seeds I received through the Rochester Public Library’s Seed Library.
The seedlings have been doing very well in their basement abode, with just the right amount of light and water (and absolutely no wind). I assumed everything was right on track for a mid-May transplant into the newly expanded garden. Then I learned about hardening off.
My friend Karen is the hero of this story. It’s thanks to her that I didn’t just stick all the little seedlings right into the dirt on the first warm afternoon. As she and I were talking one afternoon, she mentioned that she’d tried to grow plants from seeds in the past, but was always challenged by the hardening-off process.
“What’s that?” I asked, completely unaware of this very important step.
“It’s where you help the plants get acclimated to outdoor conditions by leaving them outside for stretches of time.”
I immediately bookmarked this insight for future use. A few days later, on a sunny and slightly windy afternoon, I thought I’d begin the hardening off. All the trays came upstairs, and I placed them on card tables on the deck.
“How’s everyone doing?” I asked, especially curious about the cauliflower, because they all seemed nervous and spindly in the breeze. “We’ll give it a try, but please check back soon,” the seedlings politely requested.
A few hours later, I returned to the card tables, and it was clear that everyone needed to come back inside for time to recover. The tomato leaves were limp. The squash leaves had turned slightly yellow. All the seedlings looked like they’d just made it through one of Coach Breithaupt’s excruciating middle school volleyball workouts. “That’s it! Practice is over! Everyone back inside,” I said. All the trays retreated to their basement spa.
After a night of rest and the following day spent basking under the glorious rays of the grow lights, all the plants seemed to have recovered. We’ve been incrementally hardening off ever since. Little by little, the plants are getting stronger. They seem more able to withstand the variable conditions of real life.
I’m very grateful to Karen. Had it not been for her guidance, I suspect most of the seedlings would’ve been ill equipped for the variabilities of a classic Minnesota spring.
I might not be able to put the garden in quite as early as I hoped, but I think the seedlings will thank me in the long run. They get a few more weeks of conditioning before tournament play begins.
"Holy Everything" is a weekly column by Emily Carson. She is a Lutheran pastor. Visit her website emilyannecarson.com.