I have lots of nasturtiums on my plot and I don't like to pull them up because they are so pretty. I also reckon they do a good job of covering the soil so stop it from drying out so quickly. But they are rather swamping my courgette/squash patch so I wondered, will they take much goodness and /or sun away from the veg? Given that the squash are very leafy anyway I wouldn't have thought they'd do much harm?