When to plant seeds

(Question)

Hello!
I want to plant French bean seeds as well as orange cosmos seeds in my Zone 5 (Toronto) garden. Is it too early to plant them given the unseasonally cool weather we’re having? Is there a temperature that I need to wait for?

Thanks very much for your help with this.

Etta

(Answer)

Thank-you for contacting Toronto Master Gardeners with your question about planting seeds.

Here is a previous response on the topic of vegetable seed planting dates in the Toronto area:

https://www.torontomastergardeners.ca/wp-admin/post.php?post=19941&action=edit

Of particular note, is the link to the Farmers’ Almanac calendar of planting dates at:

https://www.almanac.com/gardening/planting-calendar/ON/Toronto

You can request dates for your particular area. For Toronto, the site suggests planting bean seeds (Phaseolus cultivars) from May 11 to Jun 1, based on average last frost date. You are right, though, to consider planting on the later end of this range this year because of the continuing cold weather. The bean seeds germinate best in soil temperatures between 21C and about 26C. It is inadvisable to plant them if the soil temperature is less than 16C because they will take too long to germinate, and will therefore be susceptible to rot.

For cosmos, the Farmers’ Almanac also suggests planting after danger of frost has past (in Toronto, the same date and approximate temperature range as for beans). Cosmos germinate and grow easily and prefer somewhat lean soils. The earliest blooms will likely appear about 7 weeks after planting seeds, so you may want to risk a slightly earlier planting than with the beans so that you have flowers for more of the summer. Another time, you could try starting the seeds indoors, earlier in spring, and then planting the transplants in the garden after danger of frost has passed. This would give you earlier blooms and a longer season to enjoy these annual flowers. Cosmos sometimes self-sow if the seed heads are left in place.

Best of luck with your planting!