Kitchen Garden Forum

There seem to have been more whitefly around in the past couple of years, even flying out of brassicas in the middle of winter, but I never have a problem with them in the greenhouse.

I always grow a few Tagetes plants - French marigolds - in the greenhouse border and it keeps them away. This is usually mentioned in articles about companion planting and it definitely works.

Plumpudding

That's because they are different whiteflies altogether. I presume if you grow brassicas inside (greenhouse or polytunnel) you could get cabbage whitefly. I grow a lot of brassicas in the tunnel all year round and have not noticed any - but, as I have mentioned on the topic before, I have never seen any brassica whitefly in this part of Wales.
For greenhouse whitefly tagetes or French marigolds do seem to work. I always have some of the latter and no whiteflies, but perhaps they wouldn't have come anyway - but the flowers look pretty.

Click on the RHS links above for more info.

Alan

I'll have to try growing some brassicas in the greenhouse and see what happens.

I must say I also grow some tagetes outside among the veg in summer and don't have a whitefly problem, but only notice them in winter when there aren't any flowers about.