The Unbearable Lateness of Planting
It’s so easy to plant too early. The warm sun shines for a couple of days in a row and it can take great restraint not to rush out and plant tomatoes, basil, Caladiums, and other tender garden delights. Big box stores and some garden centers encourage such rashness with tempting displays of plants with no word of warning that they have no business going out into the still chilled soil.
I’ve done it myself, and seen my tender plants droop and die, or at the very least sulk for an extended period.
In Chicago, May 15th is usually thought of as the earliest date for planting cold-sensitive annuals. It’s not a risk-free date, though, merely the average last date on which a frost might occur.
A better guideline, I’ve been told, is to wait until the nighttime temperature stays above 50 degrees F. This helps ensure that the soil is sufficiently warm. Otherwise your poor plants might feel like a person suddenly thrown into a frigid swimming pool.
The first part of May has been unusually cold this year, and so I didn’t plant tomatoes and basil until May 22nd. They now seem to be pretty happy.
I had a challenging situation, though, with my Mexican Sunflower (Tithonia rotundifolia). This is a very important plant in my sunny front garden. I buy seedlings from Anton’s, a local nursery. I’d start it indoors from seed but my work/travel schedule makes that impractical.
These days I can’t live without Mexican Sunflower in my garden, so I made a point of buying seedlings early, before Anton’s ran out. (I don’t know of any other retailers who sell this plant in our area.)
The seedlings were purchased on May 7th. Two were kept in our south-facing back porch for a week. The other two I planted outside. These immediately keeled over, and seemed to be transmitting silent shrieks. “Oh, come on, it can’t be that bad,” I told them, but I was distinctly uneasy.
The other two I planted the following weekend. But nighttime temps were still going well below 50 degrees, and these two also seemed to languish for a week. Frankly, I thought I might have a summer without Mexican Sunflower, a dismal prospect.
Finally, in the last week of May, the weather turned truly warm, even hot. When I got back home last weekend, all four of the Tithonias looked much healthier.
Long story short: even if it tests your patience, and even if it doesn’t kill your plants, don’t plant tender annuals too early. At a minimum, it will save you a lot of anguish.