Action for May Greenhouse and patio
On the patio
Plant up hanging baskets, pots and window boxes
But don’t put them outside until the risk of frost is unlikely.
Top-dress plants in containers
Remove the top layer of compost and replace it with new compost mixed with a slow-release fertiliser. Water and feed plants regularly as the weather warms up – pay special attention to hanging baskets.
Check for vine weevil
If patio plants suddenly wilt and start to die, vine weevil grubs could be to blame. If the plant isn’t too badly damaged, pick out all the creamy white grubs from the soil and repot in fresh compost. Treating the soil with a nematode biological control will put a stop to further damage.
Soak terracotta pots
Soak terracotta pots in water before planting them up – it will prevent the porous terracotta drawing moisture out of the compost. Alternatively, line them with old compost sacks with a few holes punched in them for drainage.
In the greenhouse
Repot greenhouse tomatoes when they outgrow their pots. You could even plant tomatoes in your hanging baskets.
Pinch out sideshoots – these can then be treated as cuttings and thereby give you more tomato plants for free. Put them into pots of free-draining compost, water in and keep in the greenhouse until they root.
Alternatively, look out for plants in the garden centre.
Sow seeds of pumpkins, squash, courgettes, sweetcorn and chillies in small pots or modular seed trays. They can be planted out at the end of the month to avoid frosts.