How I keep half a kohlrabi from drying at the cut

I grated kohlrabi into a salad — half of it stayed with the cut open on the board. In a few hours the pale heart greys, the rim goes stiff like cardboard, and the crunch is gone. I shut the cut with film pressed tight at once, or lay the half cut-side down in a dry box in the cold — the stem-bulb does not give its moisture to the air.

How I keep half a kohlrabi from drying at the cut. Swede dries as a yellow root; fennel as anise after the knife; turnip as a woody heart; celeriac as soft earth. Here it is kohlrabi itself: a pale-green ball on a stem, cut kept from the air — not a new head from the stall.

A rim that already greyed I trim thin and grate the rest into salad, or cube it into a light broth. I don’t stand this stem-bulb in a glass of water like spring onions. I take only the half from our board.

I don’t need a cardboard crust instead of crunch. I need a half that still clicks between the teeth. In your kitchen is the kohlrabi cut shut at once — or does it dry on the board until supper?