Perennials

[Holly Daze]

I shall pinch them out. They will be stored in greenhouse. Fingers crossed. Thanks for your advice and guidance all. Brilliant as ever.

[Babru]

I would always pinch out cosmos so you get a nice bushy plant. However, as others have said, cosmos will be killed by frost so it needs to go under cover. Monty maybe said he was sowing hardy annuals (pot marigolds, poppies and suchlike). This is a good time to sow some sweet peas for next year, as long as you have somewhere sheltered outside to keep them. They're fine with cold temperatures.

[Holly Daze]

The variety is Cosmos Seashells. It does say on the packet that they can be sown in October. They are now 6 inches tall and look like they are going to be leggy. If I pinch them out, will they get bushier?

[nickdub]

You need to distinguish between hardy perennials and tender ones, before you decide which to sow when.

[peanut]

Monty Don suggested sowing perennial seeds a couple of weeks ago. I sowed cosmos ready for next year as an experiment. My seedlings are now about four inches tall with potential flower buds displaying. Can anyone tell me what to do now considering they are to be overwintered. Do I pinch them out or just leave them. Thank you.

Which Cosmos have you grown? The pretty pink and white Cosmos are tender and should be sown in Spring. Chocolate Cosmos is perennial but even a mature plant is unlikely to survive the winter and is best lifted.
You might be able to keep them alive indoors but they will need plenty of light. Give it a go, you might as well
But I'd brace yourself for losing them and re-sowing in Spring.

[Plot70]

The frost will pinch them out for you.

[Holly Daze]

Monty Don suggested sowing perennial seeds a couple of weeks ago. I sowed cosmos ready for next year as an experiment. My seedlings are now about four inches tall with potential flower buds displaying. Can anyone tell me what to do now considering they are to be overwintered. Do I pinch them out or just leave them. Thank you.