[Grubbypaws]

I grow my PSB in large containers. Every year I change the compost but is this absolutely necessary?

This year I am short on compost and was wondering whether it would be possible to use the same compost for a second year running?

[Hampshire Hog]

Two factors I would say exhausting nutrients and crop rotation.
I think you could address the first issue with fertiliser but the second is more complex.
(Potentially harbouring pests or disease) Ideally you could use compost from a pot that has grown a non brassica in the previous season. If that’s not an option I would just boost the fertility and cross my fingers.
Good luck HH

[Grubbypaws]

Thanks HH. Have you any idea how high the risk is? I have always rotated crops before but it is going to be difficult this year. However there is no use planting out if it is more than likely that not that I will run into problems.

[Hampshire Hog]

Not really sure how likely the risk is based on one season. Like you I have always used fresh compost perhaps one way to go is to use as much fresh compost as you have for a couple of pots and old for the others. If you mix them you spread the risk to the whole crop. Other thought is whether you have any garden soil you can use to bulk up compost. See if anyone has further thoughts.  Cheers HH

[Mr Dog]

 I wouldn't have second thoughts about going for it. The absolute worst that could happen is that the plants become diseased and die and you end up with no PSB, but you'd have to be pretty unlucky for that to happen. Don't try and you definitely won't get any PSB!
Much of my compost from last year is being reused rather than going onto beds this year due to the difficulty in getting fresh.

[JoshP]

I think it would be fine. The main risk would be clubroot but this can be prevented by liming the soil. Adding some fertiliser would sort out the nutrition side of things