When to pot on my cucumber?

[Babru]

Thanks to you all for your sage advice. I've potted the plant with the most roots showing to an intermediate pot, gravel on the top and a paper collar for sciarid protection. It's been back under the growlight for a couple of days and seems so far unscathed. Second plant has its paper collar and I will plant into a much bigger pot when the time comes.

One will stay in as a houseplant, one will go into the greenhouse.

Looking forward to some tasty cucumbers this summer, and with two plants, hopefully enough to share.