My kale stopped growing. It's been stuck in space and time for a few weeks now. What's going on?

Have they not started making flowers yet.

I planted mine outside and they didn't thrive in the dry spell and bolted very soon.

I never knew they could be grown in pots.Why not see if you can knock them out of the pots ?

Turn them upside down and see if the plant is rootbound.

You seem to have done quite well so far .Maybe they have come to the end of the road but you can still eat the flowers and the stalks if they appear⁹)

I don't imagine you would get as good a harvest in a pot as outdoors ...

To look at the roots you just turn the pot upside down carefully and tap the bottom with one hand or with something hard.Stop the plant falling on the floor with the other and take a look at the roots.

If they seem to have plenty of room then that is not the problem.

Could you have overwatered or damaged the small leaves that grow between the stem and the big leaves when you harvested them?(I think they would be hard to damage as they are so small at first)

I hope someone else will advise you .They probably have a better idea than me.

Btw what is "10 litres " in your op?Not 10 litres of soil in the pot,surely?