We always keep picking them until they 'feel' a bit hard when you put a knife to them. Always try and pick all of them so that new ones grow throughout the growing season. When they start to get a bit hard, we will leave them on the plant and save them for planting next year. As soon as they have dried out, pick them and dry them further by lobbing them in a box indoors. When they are proper dry, take them out of the pods and put them in a jar.
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Our courgettes have been amazing this year Mabon. Again, keep picking them so that they keep coming. Peas should climb about three foot (ish). We use old broken canes that aren't big enough for the runner beans any more. Like you say, they go a bit straggly though.
Anyone grown any Parsnips this year? Ours haven't done as well as usual.
Leeks plants (from neighbour) are going in. One of the few veg to keep you going through the winter months.
Broccoli just didn't happen.