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.

cold 2
Don’t do this to your plants.


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.

Recently planted tomato.

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.

“Eeeeek! The soil is too cold!”

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.

Feeling better now, but you can still see leaf damage.

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.

64 Comments on “The Unbearable Lateness of Planting”

  1. The 15th May is our cut off day too, I’ve never known a frost after that day. I’m usually playing catch up so am never tempted to put things out too soon, it’s a question of whether things will get put out at all!

  2. Even in a winter when there was only one or two nights of frost May has been distinctly cool so peppers and egg plants that where planted out simply haven’t grown at all and the soil is warm so it is night time temperatures that are making my plants sulk.

  3. Glad your Tithonias will make it. I noticed people planting things early here (April 15 is our avg last-frost date), but the wise “old-timers” down the road just set out their tomatoes about 10 days ago, once it had finally warmed up, and they took off.

  4. That is the average date here too, but then we had just 2 degrees above zero later that week! I managed to keep my seedlings relatively warm (including Tithonia which are not sold anywhere as plants here) and they are only just perking up, but hopefully they will catch up now as it is much milder at night. I couldn’t imagine your garden without Tithonias either, as they were the inspiration for me to grow them too and I just adore them!

  5. I think a lot of people in our area got caught by surprise with the late cold temperatures, especially after such a warm start to May. Fortunately, my procrastination and lack of time paid off for me this year:) I started my Mexican sunflowers from seed, and they’re looking pretty good–can’t wait to see them bloom here!

  6. Sunflowers are deceptively fragile, even the ones started by spilled birdseed in my yard don’t always make it (that is, the ones I decide to let grow). I’ve gone on a planting binge just this weekend of native grasses and wildflowers and I’m glad they weren’t shipped until May 25!

  7. Glad your Tithonias have perked up and are now enjoying the sun! Mine have just been planted out and are acclimatising to their new homes!
    So many people are taken in by those displays of annuals in the garden centres and assume that , as they are for sale, then they can be planted straight out.
    We try to wait until the last week of May just to be on the safe side, and we are in the East Midlands of the UK.

  8. Good words of advice! Most years, I wait until Memorial Day to plant tomatoes, peppers, and tropical annuals (even though our local garden centers say Mother’s Day is usually safe). This year, I started a few days earlier. It really doesn’t pay to get them in the ground early because they don’t grow much until the weather gets warm, anyway. It can actually stunt their growth to plant before nighttime temps are consistently above 50F. Plus, as you say, it saves the gardener from worry. 😉

  9. I tried once and failed to grow Tithonia direct from seed outdoors.

    Don’t know anywhere around here that sells the seedlings.

    So I’ll have to try again from seed someday. And when I do, I’ll be sure to follow your advice on setting them out after last frost date (which here tends to be around April 18th, I believe).

    Good luck with your garden this spring and summer!

  10. In Maine, Memorial Day is our planting date for tender annuals, and my gardening father drummed this so firmly into my little head that I do not deviate. But I do understand the impulse 😉 Glad your flowers made it.

  11. Glad to read your plants recovered Jason, always a risk to get carried away with ourselves when the weather takes a brief turn for the better. I accidentally left some Dahlia and Begonia plants outside one night and lost the lot 2 weeks ago!

  12. Memorial Day weekend is our time for planting tender annuals. This year, I put some (like morning glories) out a few days early because we had an unusually warm May and the forecast did not include any chance of a surprise late-may cold snap.

  13. Oh, I shudder when I see people around here put out their marigolds and petunias in early May or even late April because we’ve had a week-long warm spell! I generally wait until Memorial Day to put out any annuals besides pansies. This year, I went a little earlier, but not before I analyzed the long range forecasts and was 99% certain the nighttime temps wouldn’t drop too low! Now, your post has reminded me that I actually have started some late-started Tithonia under lights in the basement, and I better go water them now! One nursery near me started selling the plants this year, but they want $3.99 a piece for them. I decided I’d rather start them from seed, even though it’s a bit late for that.

  14. Hello Jason, we had an extended cold Spring that was so late that the difference between a dreary cold day and full clear sunshine the next day could be 15C. The plants didn’t know what was going on, I didn’t what was going on, the weather forecasters didn’t know what was going on. Thankfully, things are starting to calm down and warm up but Spring must be the riskiest month for gardeners.

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