With there being very little chance of the ground being dry, now is a good time to mulch your borders to feed them and retain some of that moisture during active growth of your garden plants. April and May can be a busy time in the garden, and if you mulch now you suppress that first irritating flush of annual weeds.
Keep an eye out for greenhouse pests. Catch them early to avoid an outbreak later on in the year which will be much harder to control.
Start sowing your seeds. Keep them well ventilated and prick them out early to avoid damping off.
As perennials begin their active growth, it is a great time to divide the clumps. By dividing in the spring the plants remain active and will recover from the division very quickly.
Chit your seed potatoes in a cool, well-lit place. By giving them lots of light and cooler temperatures you avoid the drawn, alien-like growth when it comes to planting time.