What is eating these cabbages?
A close look reveals no caterpillars or caterpillar poo anywhere on the leaves. There are no silvery slug and snail trails on the leaves or surrounding compost. The obvious culprit is a peckish pigeon.
This problem can be easily avoided by making hoops over the plants and then pegging down an old net curtain over the top before any fat pigeon comes waddling along looking for a nice fresh bit of salad.
One of the allotment plots was planted up with peas. Within a short time they were a low-growing matted mound full of aphids. Always put in peasticks when you sow peas (you can just prune them off a nearby shrub like Buddleja) so that they grow tall towards the sky, not slump into a muddled tangle. Having plants with a bit of growing room makes it easier for you to pick off any pests too.
You can see little white specks on the leaves. These are the shed skins of aphids who have got so fat on delicious easy to reach pea tangle they've split their skins and grown a new one. In the top half of the picture you can see the red and black crocodilian larva of a Harlequin ladybird. Although they eat aphids they also eat native British ladybirds.