[missmoneypenny]

My onion sets should be arriving today or Monday. Is it too early to put them in? Nice weather forecast for next week, then cooler but no frosts forecast for the week after. I’m in London. Thank you.

[Blewit]

Mid March to mid April. If you plant them too early they're more likely to bolt. Hold back with red onions sets until mid April for the same reason.

[missmoneypenny]

That’s really helpful thank you Blewit.

[Nobbie]

Mid March to mid April. If you plant them too early they're more likely to bolt. Hold back with red onions sets until mid April for the same reason.

Never heard that about red onions before and always have trouble with them bolting. I’ll give it a go this year.

[mumofstig]

I've planted mine in modules in the greenhouse, so they get a good start..

[Sparkyweb]

I've planted mine in modules in the greenhouse, so they get a good start..

This is interesting. Is the greenhouse heated?
I assume you’ve just used normal compost?

[mumofstig]

Greenhouse heated? No. Ordinary compost? Yes, anything laying about  it's only to get them started - they'll be planted outside in a few weeks weather permitting.

[Sparkyweb]

Perfect! That’s this afternoons job sorted then!

[Alank]

I always start a few early in the greenhouse and save the rest to plant directly during March/April the later ones being for storage over the winter.

[missmoneypenny]

That’s interesting. I don’t have a greenhouse but my shed window lets in a decent amount of light so I might try this.