Brassica seeds won't germinate for fall crop

[herritzj]

I really want to have a fall garden in our zone 4B land; last frost typically end of September. I have attempted to start several kinds of seeds, but NONE of them are sprouting! It's been over a week.

I'm using the same seed-sprouting mix I used in the spring, and some brand new/some seed from the spring, Broccoli, brussel sprouts, cauliflower, and cabbage. I used a similar method - small plastic-sectioned pots, seed starting mix, planted 1/4 inch deep, and watered. They pots are in a seed sprouter with a clear top, with gentle bottom heat. Soil is moist, but not wet. And not a single seed in about 10 days!

Do I just need to be more patient? Should I put them outside? I don't have a light over them this time, like I did in the summer, but they are near a window (no direct light). Am I starting them too early? Or is the heat the problem? Our house with A/C is 78-80, but they are in the kitchen, which tends to be a tad warmer. Should I put them in the basement? If so, do they need any light at all to sprout?

Thank you for your help! This is my first attempt at a fall garden...
Jenny

[Tutter]

Take them off the heat! If it's 80 degrees and you have them on bottom heat, that's too hot for brassicas.

[mayfair69]

Brassica do not need bottom heat to germinate. OG mag a for years also showed this is detrimental to Brassica seeds.

[Mulligan Man]

I have always had faster germ with bottom heat in my basement.

[Ohiorganic]

Brassicas won't germinate in soils over 85F and prefer a soil temp between 60F and 70F so don't bottom heat right now and consider putting the soil in the fridge for a 1/2 hour or so to bring down the temp to under 70F.

No they do not need light to sprout. As a matter of fact we usually cover our soil blocks with a sheet of black plastic to aid in germination of brassicas.

[herritzj]

Thank you all, that's most helpful! I didn't write down the date I planted them, but it's probably been 10 days to two weeks. Do you think I should start over? Would the seeds have rotted by now? Either way, I'll put my tray in the basement and see if anything happens.

I feel like a kid doing a science experiment! Hopefully the results are tasty...