How far apart to plant sempervivum (house leeks / hens & chicks)?

[Aridane]

Just that really!

I want in due course for them to be a carpet of sempervivum - was but not sure the balance between planting them to far apart and they never 'join up' or spread quickly enough and planting them too close for immediate impact but they then get overcrowded quite quickly

Went online and what I found wasn't that helpful in this regard

Are they going to be different varieties/species? I think it depends on which ones you want to plant. Some will grow larger than others, so it's a bit difficult to say. I suppose most will grow to about 6" across eventually, so maybe space them 6-9" apart. Again, some will probably spread more quickly than others. If they get too crowded, it's easy to remove the outer offsets, but remember that flowering rosettes will die, which can leave them looking a bit gappy.

They will all be the same - cobweb house leeks (Sempervivum arachnoideum) although x1 tray are yellow ones and another tray red ones

The offsets root easily. So err on the side of too close because you can easily transplant some if they get too crowded.

Ah, good point!