Crabapple seedlings planting.

[ducreamious]

I have been doing a test the last few weeks with crabapple seeds from an ornamental crabapple tree. Here's what I've got so far. I collected maybe 20 crabapple mid January. They were still on the tree, but pretty dried from sitting there so long.
I extracted the seeds from them and ran a few tests. In the begining, I made two plastic bags with moist paper towels and about 5 seeds in each. I put one bag (Bag One) on top of the fridge where it's slightly warm and one bag (Bag Two) inside the fridge to mimic stratification, because I wasn't sure if the winter they had already been through had been good enough.
The first bag (Bag One) has one seed germinate within two weeks, and once the small plant got its leaves out of the seed and the root had grown to about 1/2-3/4”, I put it in some germination mix (Probably about another week). I also put a plastic bag on top in effort to retain moisture. I set this by a west facing window. Then I moved the seeds in the fridge (Bag Two) up to the warmer spot above the fridge. Around this time I also placed another newly gathered set of seeds in some seed starting mix 1/4" deep under a grow light and on a heat mat (Soil Seeds). I also placed another new wet paper towel in a baggie with some seeds on the grow mat (Bag Three). Now, a week and a half later three seed have started from the plastic baggie that went through the fridge (Bag Two, see picture), no more have started from the bag that has been on the fridge the whole time (Bag One), and none have started from the soil mix (Soil Seeds) or the bag on the heat mat (Bag 3, however the heat mat bag seeds look they might be opening a little bit).

Some quick notes:
The bags that are in the warm spots develop yellow mold so the paper towel is changed every week.
I'm in urban Minnesota and it has been super warm this winter, so that could explain why the seeds benefited from extra stratification.

So, I'm looking for more information on planting these guys.
How big should the seedling from the bag be before I put them in a pot?
Should I put any in the ground after the threat of frost has passed?
How long can they survive inside?
When I run more tests what should I try next? I've heard of possibly rehydrating in water, or possibly scarification, what do you guys think?

 

[SeanS]

I’ve found crabapples are hard NOT to germinate, they’re super easy to grow from seed and fun to develops.
Good luck with your crabapple seedling goals of 2024

 

[ducreamious]

I’ve found crabapples are hard NOT to germinate, they’re super easy to grow from seed and fun to develops.
Good luck with your crabapple seedling goals of 2024

Epic, thanks!

 

[Deep Sea Diver]

One can stick the germinated seeds immediately into premoistened seedling mix, in a nursery pot or 2 1/4” pots for the first year.

Cheers
DSD sends

 

[ducreamious]

One can stick the germinated seeds immediately into premoistened seedling mix, in a nursery pot or 2 1/4” pots for the first year.

Cheers
DSD sends

Thanks. I planted them in a small nursery pot.

 

[Shibui]

Transplant seedlings is not all that critical. They can go in a pot any time after you notice the radicle (root) appear but can also cope with waiting until the leaf shoots also grow.
Long roots can be clipped short. That's a good way to encourage more lateral roots for future nebari.
Seedlings seem to cope with root pruning much better than older trees. I frequently chop the radicle really short and have no problems with any species I've tried that with.

Seedlings are usually transplanted into 4" pots here as smaller pots are just too prone to drying out.

When I run more tests what should I try next? I've heard of possibly rehydrating in water, or possibly scarification, what do you guys think?

All the advice I've seen on apple seed is they require stratification for reliable germination.

I'm in urban Minnesota and it has been super warm this winter, so that could explain why the seeds benefited from extra stratification.

Your 'super warm' may be relative. My guess is that super warm up there is equivalent to extremely cold down here. Stratification temps don't need to be super cold. It's mor about chill hours/days. Fridge temps are sufficient but I've read that freezing may shorten the time required. I believe that stratification needs moisture to be effective so dry seed in the fridge, and probably in dried apples on the tree, does not count.

When I run more tests what should I try next? I've heard of possibly rehydrating in water, or possibly scarification

It will be interesting to see if scarification helps apple seed. The seed coat is not tough or waterproof but if the germination inhibitors are in the seed coating then scarification might just remove enough to allow germination.

Rehydrating in water is probably similar to warm stratification. Some germination inhibitors are water soluble so soaking can sometimes help. We have a few species of Aussie native plants where seed is leached in running water for 1-10 weeks to get better germination (suspend seed in a mesh bag in the toilet cistern so it gets washed with fresh water whenever the toilet is flushed)

@SeanS is spot on about apple seed germinating easily. I've had supermarket apples where the seeds had germinated inside the apples.