How to overwinter summer/autumn-sown flowers?

[jonahjonah]

Hi all,

I'm sowing some flower seeds in the greenhouse now to try to get earlier flowers next year. The areas where they'll grow next year are not clear yet, so they need to be sown in my GH. But I have no idea what I'm going for... Examples of my clueless questions include: after I get seedlings, am I potting on into ever larger pots? Am I trying to maintain at minimum size? Do some varieties need planting out before winter or protecting indoors instead of spending the winter in the unheated GH? How much water will they want if they stay in the GH?

Basically, I need a dummies guide because I've heard of overwintering but have no idea what I'm about. Any good resources for me?

Thanks!

[nickdub]

You probably need to tel us what sort of flowers you are planning on growing - some are hardy for example, which means they can go outside even in frosty weather + others really hate to be too wet etc.

[jonahjonah]

I've got poppies, foxgloves, cornflowers, Veronica, Ammi majus, hollyhocks, pansies, violas, larkspur... I'm sure there are more but they include hardy annuals, perennials and biennials. I have a small GH, about 6' square.

[annie8]

Will be keeping an eye on this post as I’m new to flower growing too. Can I ask another newbie question. Should I use seed sowing compost or mpc for things like foxgloves etc.

[Babru]

I had an opened bag of seed compost but didn't put a clippy on it to keep it closed as I usually do. Result - found a load of slugs had set up home inside the bag.

I've been using a bag of mpc since then to sow seeds, and so far they've been fine. I've sown foxgloves, wallflowers, salad leaves, knautia macedonica, echinacea, basil and winter pansies. They've all come up fine. I think perhaps if your seeds are extremely tiny eg begonias, then maybe they would struggle with the coarser mpc. However you could top with vermiculite to get past that.

I've been using mpc for cuttings too. Some have worked, some haven't. Is this to do with using mpc? Who knows!

[nickdub]

poppies, foxgloves, hollyhocks can overwinter in the ground outside no problem - you can start them as seeds in trays or sow direct in to the soil, but you can only move the seedlings when they are really small, as soon as they start to get longer roots it becomes v difficult.

Pansies I would over winter in some sort of container as seedlings, they are quite hardy so don't need much warmth, but they are favourites with slugs and snails, so keeping them away from attack is sensible.

I'll leave someone-else to comment on the other sorts of flowers you mention as I don't feel too confident on them.

[Mitzi]

I sowed hollyhocks last autumn and overwintered them in small pots. They havent flowered this year. Would have been better in the ground but the bed wasnt ready.

This year I am going to put half my seedlings in the ground and the rest in pots.

You mention poppies - they don't transplant well so if you can't direct sow now, I'd leave them until spring.

[jonahjonah]

Thanks for the advice! I'll prioritize getting the flower area clear for the ones that want to be in the ground. Although I am lazy about potting on, I still prefer seeds that can be sown indoors because I love watching them germinate. Probably not my most practical concern though.

I hope it is helpful for you too, Annie. Although I'm obviously no expert, I sow into mpc. I just discard big, woody bits and try not to keep the pots too wet, to avoid damping off or anything like that.