I’m in southern Ontario (zone 6b) and just received an order of seeds from Prairie Moon, many of which require 60 days of cold stratification. Have I missed the window for container sowing outdoors? March can often see temps above 0 Celsius. Wondering if I should play it safe and do the fridge method instead. Any advice would be appreciated!

by forgotten_meadow

7 Comments

  1. CharlesV_

    Cold stratification works with soil temps below 50*F. You should be fine for all of these, but if you’re concerned about it, you could also try artificial stratification (damp sand, seed, and ziplock in a fridge).

    Edit: sedges are a little trickier. You’ll want to have these in trays and in the spring have them in a spot where they get bright sun mid day, but mostly shade in the evening and morning. Temp swings are important for stratification for many woodland sedges.

  2. UnhelpfulNotBot

    I sow well into February. Adequate stratification temperatures can be reached in May here, I imagine Ontario is similar.

    If I sow in February, I’ve got the entire months of March and April for stratification. 60 days is typical for most species.

  3. GemmyCluckster

    It’s worth a try. Maybe sew a few now and save the others for next year.

  4. PrairieTreeWitch

    I got a bit freaked out yesterday when the temp spiked above 50, and have started creating a backup of all my C(60)+ seeds in the fridge using the coffee filter method.

  5. NotAlwaysGifs

    Nah, plenty of time. 60 days is not a hard and fast rule. It’s just the recommended amount for good germination rates. I snow sow most of my native wildflowers in early February, and I’m 6b/7a with an earlier last frost date than you.

  6. FateEx1994

    Most these are like 30-60 days.

    They’ll probably germinate fine if you get them out there today.

    Temps are below 40 for the next 2 months most of the time.

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