Garlic and onion store super well. We still have some 2 year old garlic which has done fine. Cool dark place and you are good to go. Potatoes can start to root up over time but still perfectly edible. In ground storage for root veg seems to do well for us as well (although some of our carrots end up a bit wonky looking) but wouldn’t leave potatoes in once the ground is getting too wet.

I think cucumbers did particularly well last year due to all the rain and just enough sunshine too. Cucumbers are heavy feeders though so we usually fertilise them every couple of weeks (with homemade fertiliser so it’s cheap).

With our brassicas once it’s white butterfly / caterpillar time we put insect netting over them. Mitre10 had some reasonable insect netting cloches which are fine to start with. We find them quite prone to bolting if they get too much Sun so also recommend planting them in a semi shaded area of your garden. Over summer the area we plant them only gets 3-4 hours of Sun a day and that seems to be plenty.