If you go ahead and grow some kale I bet the cabbage whites won't be invisible to you for very long, LOL! My kale! So beautiful one day and then, the next day, full of holes! And on one leaf, three fat green cats lined up munching away!
I left them there! Because I have other sources of kale and they don't, really. So. And they've finished and those plants still have good leaves on them. But the ones I watched the female lay eggs on, those I did wipe the eggs off because, enough is enough. And hey, they weren't cats yet!
