I can’t help you with any of the information you seek. But I am just curious as to the reason you are pregerminating hardy tree seeds in the fridge when you live in Canada. I’d just have sown them in pots and left them outdoors until spring. (With wire netting to keep creature out.) Bags in the fridge or soil blocks just seem like a lot of fiddly and unnecessary extra work.

I tried sowing them in pots outdoors & planted them directly in the soil as well. NONE OF THEM SPROUTED.

So.......I decided to try the directions on the package & cold stratify them.

So now they're in the fridge in a Ziploc-style resealable bag. But the cold stratification process, as I understand it, is to get the seeds to sprout. What I was wondering is if you can get them to sprout directly out of the soil blocks.

If your seeds get the required length of time at proper temperatures, for cold stratification over winter, in the spring they will sprout. It really doesn't matter what type of media they're in.

I've planted single seeds in pots before and put those out in the freezing temps out in the garage to cold stratify. They are already in a pot when they sprout in the spring, so they grow on until up potting is needed.

I guess my seeds don't care, as they never took. Oh well.

Yes I considered that the seeds may be bad. I'm hoping this time around will be different. :)

Such an addictive hobby.

All sorts of reasons for a no-show. I cover my bases by sowing some into 4inch pots in the cold greenhouse and some in vermiculite (or perlite, compost, sand, kitchen paper) in the fridge. They need water, oxygen, sometimes light and time. Sitting in the fridge in a packet does not count as stratification (sounds obvious but wasn't, for me). Sowing in pots can be fraught - mice will dig up seeds, birds will scratch the soil surface rooting for insects, pots get too wet, too dry and timing is very variable. I don't give up on a pot until late May and will try to hang on for a coupla years (although labels go astray).

I have never tried soil blocks cos I worry that they will fall apart, get too dry, will crumble with any movement and so on. I don't like using little modules either because it is hard to keep the mix at a stable level of moisture. I don't like trays/flats because tree roots seem to seem more space than a tray will offer.

Yes, it is a ridiculously addictive hobby. When your first, seed grown trees are fruiting and flowering above your head, it truly is intensely satisfying and unforgettable (mine are sorbus species - a genus I have always loved. Named my first-born Rowan. Best of luck, yms. Belts and braces. - you will find methods which work well for you.

If you are using seed you have collected yourself, I guarantee you will appreciate the increased viability of fresh seed.

I am TOTALLY LOVING this process. At first it was me trying to get my seeds to germinate.

NOW it's me TRYING TO PERFECT SEED GERMINATION. 😂🤣