Simple wicking box butterfly excluder

I’m determined to grow a good crop of brassicas this year. As well as the usual kale and broccoli, I’m going to have a go at red cabbage. I’ve been buying it recently and love it—sliced, steamed and dressed with a splash of balsamic vinegar and a sprinkle of raw sugar.

I always seem to put brassicas in too late and they don’t get much growth on before they’re slowed down by the cooler weather and winter. Then annoyingly, I find them running to seed in early spring.

I note that some of the other food-growing bloggers in Melbourne are sowing their brassica seeds in January, so this year, I’m doing the same.

But Cabbage White butterflies will be around well into autumn. Even though the hot weather has all but eliminated them at the moment, I wouldn’t be surprised if they make a comeback when it gets cooler. So I need to keep them off the plants right from the seedling stage.

So—covers for the wicking boxes are needed.

Easy! Just poke a short stake into each corner:

Two lengths of poly tubing over the stakes:

And some fine netting over the top:

That should keep the little so and so’s out! I should stress that the netting should be fine. I’m using mosquito netting, but any old lace curtains will do. I’ve seen Cabbage Whites get through wire mesh with a 1 cm opening. Bird netting is too coarse, too. I don’t know how they do it—just seem to fold their wings and they’re through. They’re very persistent where their food plants are concerned.

I’ll be potting up seedlings in the polyhouse but will want to put them out in the open eventually to grow on, so I’ll just put the tray of pots under the cover, on the surface of the box, until they’re ready to be planted out.