Vernalisation - without waterlogging!

I have some seeds that want a cold spell to germinate.

I could sow them in a pan, as normal, and put them under the greenhouse bench - and hope that I remember to water them periodically ... and if we have a mild winter maybe they won't get enough cold.

Or I could put them outside, but they are liable to get waterlogged.

If I moistened the compost "just right" could I put the pan in a plastic bag and put that outside? It shouldn't then need any watering as condensation will be reabsorbed.

Is the plastic bag liable to perish over-winter? or be eaten-through by mice etc?

Or is there a better way?

I've used the coffee-filter / "baggie" method in the past and not had good results. I think that was because I didn't allow enough air in the bags ... but I could retry that method, with the benefit of hindsight

 

I wish! Needs to be damp-cold, like being in the ground, rather than just "chilled" like Smoked Salmon I'm afraid :(

 

Are we talking about stratification?

If so the usual method is plant the seeds as normal, top off with course grit and place outside in a shady spot.
The grit stops moss growing.
If it gets too wet you can put something like a house tile over the pot, but if the compost is well drained its not needed, might keep the mice out though.

 

Try the freezer for a day or two.

 

Yup. (Never understood the difference, if there is one?, between stratification and Vernalisation).

If I cover it with a tile then won't it dry out? (not if I remove it periodically, of course!) but I wanted a zero maintenance method, hence I was thinking that a plastic bag would maintain the pan at correct moisture content.

Let's assume we are talking 100 such pans ...

 

I was put off my by previous failures with Baggie method, but thinking about it I think I know what I did wrong then (no air), so I could have another go. At least with anything that has plenty of seed I could do 50:50 Fridge/Baggie and a pan outside for the other half.

 

As I understand it, stratification refers to subjecting seed to cold and frost in order to promote spring germination.
Vernalisation refers to subjecting plant to cool temperatures in order to make them flower, not something we really need to do in the UK, it just happens naturally.


If you have that quantity, then I think I would just go for the well drained compost, checking the plastic bags for germination in spring might be a problem.

 

Ah, my mistake, sorry. I got confused by this in Wikipedia "Vernalization (from Latin: vernus, of the spring) is the acquisition of a plant's ability to flower or germinate in the spring by exposure to the prolonged cold of winter"

On further reading vernalisation can be used on seeds to make the [resultant] plants flower earlier.

I was thinking clear plastic bags, or am I misunderstanding a potential problem?

 

OK so I might be wrong on vernalisation, just always known the cold treatment of seed as stratification

Just think you need to remove the plastic bags immediately on germination, the bags will be covered in condensation on the inside, so might be difficult to spot small seedling actually through the bag.

 

Ah, good point. On my little 1/4 seed trays with plastic lids, in the propagator, they get enough condensation to become opaque. I give them a good hard tap to knock the condensation down ... I guess I'll do something equally brutal with the seed pans & plastic bags! But its a good point, need to catch them at just the right moment. I'm not good at that sort of regular attention ... FingersCrossed then

 

I have only ever put Allium seeds, in a pot, outside in November in a plastic bag and looked again in the new year to find hundreds of seedlings. Worked a treat.

I would be inclined to cover them - saves random seeds from elsewhere being blown in, as well as excess water. They won't dry out in our winter climate. The bag doesn't have to be a good fit if you are worried about the seedlings not getting fresh air in spring. The wind will see that it does.

I think vernalisation is a cold treatment that can apply to plants as opposed to just seeds. Its thought to produce a chemical called Vernalin in the apical bud tips, which stimulates growth. But Vernalin has never been isolated.

 

I germinated some hellebore seedlings last winter/spring by sowing them in trays the previous autumn, watering them and then just popping them in a sheltered shady spot under a large shrub next to my greenhouse (not so far under that they didn't get some rain on them). Come the spring I got close on 100% germination.

I also germinated hazel, sweet chestnut and horse chestnuts all needing exposure to cold/damp over winter, they were sown in pots and large cell trays and popped in my home made coldframe. After inital watering they stayed damp all winter and germinated well in the spring.

 

That's my plan ... but I just wasn't confident about leaving the pots open to animals / birds. I'm going to bag them and see how I get on, I'll try half the seed now, and may try some in bags in the fridge too (which didn't go well for me last time I tried it :( )