Now is a good time to sow some of the less hardy varieties, such as courgettes, "outdoor" cucumbers, french beans (dwarf or climbing) and runner beans. Take care though, as these will all take fright if they get cold or too wet. I haven't mentioned tomatoes as ideally they would have been started off with heat earlier on, but maybe plants can be procured for growing on in a greenhouse. The same goes for peppers and aubergines - they do need a bit more nurturing.
Courgettes, french beans and runner beans on the other hand are fairly easy to look after and will grow well outside given a sunny position and some shelter from the wind BUT won't tolerate frosts.
These wee cucumbers, "Small Green Paris" would normally be described as gherkins. They are really cucumber-y in flavour. They don't have complicated pollination requirements as some cucumbers do, but will do best in a greenhouse.