Brassica's going white and dying

[Jonnyt]

Hi,

I've had some cabbages and purple sprouting with the leaf tips going white the the plant dies.

Anyone know what's causing this?

[burnie]

Tell us a bit more, where are they planted, have you just put them outside recently, are they in soil or in compost? All helps as do photographs in getting to the bottom of the problem

[Jonnyt]

They are in Compost and it's happened in both my Greenhouse and outside in pots

[nickdub]

Try knocking one of the affected plants out of its pot and see if anything is eating the roots, would be my first move.

[dammad49]

I have the same/similar problem. Lost most of my overwintered caulis about 6 weeks ago, now the Romanesco seedlings are going the same way. They are in GH, in virgin compost. Nothing visible on roots/in pots?

[ameno]

It's sun scorch/scald.
I get it quite often. Some crops are more sensitive to it than others (cucurbits and French/runner beans are very sensitive, peas, lettuce and brassicas somewhat).
You get it worst when you transfer the plants somewhere much brighter than they are used to without giving them an interim period to adjust to brighter sunlight.
If the plants survive then new leaves should be unaffected, and it doesn't affect mature plants usually. Symptoms tend to be worse with outdoor plants, as not only is the light stronger but they also have the drying effects of the wind, and they'll also be worse if the roots are allowed to dry out (although this isn't what causes it in the first place).
In future, you should give them plants a "hardening off" period, but to harden them off to the intensity of the sunlight, not the cold. Move somewhere brighter than their starting location but not as bright as their final location for a couple of days first, then move to their final location.