Perennial seedlings

pitter-patter

I’ve grown some perennial plants from seed (Gaura, Dierama, Potentilla, Penstemon barbatus, Verbena rigida and aquilegia) and I was wondering whether they can overwinter in a plastic greenhouse. I am planning to pot them separately and plant them out next spring. Is that a good idea? Thank you.

Ceres

I don't think you have a choice really. If you bring them indoors they will grow leggy and weak. They are still very small so there is no guarantee they will survive the winter in a greenhouse but they have a better chance of growing into strong plants if they aren't mollycoddled. A lot of perennials will be self seeding in the garden right now and a great many of those will be fine over winter so some of your plants should survive.....maybe all of them.

Borderline

Over wintering in a plastic greenhouse is fine for all. Most of those apart from maybe Penstemons, should be fine even tucked under a sheltered southerly wall. It's the extreme wet that may damage them, so a greenhouse will be a bonus. In terms of planting out next year, I would delay the Penstemon and Gaura till early summer. It's better to see that they have bulked up first.

Posy

Dierama grow quite slowly and are vulnerable to slugs when small. I also find I weed them out by mistake sometimes when they are in the border so I would wait until they are a year older before you plant out. They resent disturbance so pot up as seldom as possible.

pitter-patter

That’s very helpful, thank you all.

Lyn

Whatever you chose to do, don’t feed them, that won’t help them. 
They are a bit small, March would have been best to sow the seeds, but some will overwinter as they are hardy. 
The guara may not survive outside, some places it doesn’t survive the winter as big plants. 

pitter-patter

I don’t mind keeping them in the conservatory or garage window sill if that works better.