Wintersowing Lessons Learned

Our cold snap last weekend really demonstrated how well winter sowing works for perennials and hardy annuals, and how tricky it can be for the tender annuals. I think we got down to about 25F!

All the examples below were planted on February 25th, by students in my Get Growing! class, using all the same size containers and same soil. Even though the containers were frozen to the patio on Wednesday morning, the hollyhock and coneflower seedlings were unfazed.

Cleome, an annual, also seemed pretty happy. The leaves in contact with the plastic were dead, but the others looked good.

Unfortunately the tender annuals did not fare as well. The zinnias looked sickly even before the cold snap and the cosmos were very slow to germinate. Now they are mush and must be replanted.

In retrospect, February 25 was much too early to wintersow the tender annuals here in Cambridge. In the future I'll wait until April 1 to start those in wintersowing containers or just make space for them indoors under the lights. You can also sow those sorts of seed directly in the garden. I only bother starting early because we've got a short growing season here and I want to see zinnias before September.

To make myself feel better about my frozen flowers, I stopped by the big box store to gloat over the massive tomato & pepper miscalculation. And then I bought some more seeds, naturally.