May in the Garden

By Glyn Smith Head Gardener at Erdigg Hall National Trust Garden

After all the rain we have been having lately, we will be busy catching up with our lawn mowing and planting. The greenhouses and cold frames at Erddig are full to bursting with young plants, just waiting to get out into their beds.

We will make sure that all are hardened off properly before planting. Hardening off is when plants are slowly subjected to cooler conditions, before trusting them to the weatherman. The usual way is to put them into a cold frame. This can be fully ventilated in the daytime, closed at night, or propped open a gap as they get used to cooler conditions. Look out for slugs and mice though, as they can easily damage young seedlings.

Plants like sweet peas, chrysanthemums and young herbaceous perennial seedlings are pretty hardy and can be planted out now, as can many vegetable plants. Some outdoor sown vegetables and salads may need thinning out. Don’t waste those lettuce seedlings, they can be planted out to give a later crop. It is not too late either to sow hardy annual seeds directly where they are to grow.

Tomato and cucumber plants are in the garden centres. They can be planted in the greenhouse now. Wait a while before planting outdoors.

As their shoots emerge, Potatoes should be earthed up. This protects them from late frosts and the potatoes will grow in the dark. Green potatoes that develop in the light are poisonous.

If you have not fed your lawns yet, now the ground is moist it will be a good time. Time too to consider controlling any moss, by raking, or with a moss killer.

Stake herbaceous perennial plants now whilst they are still small and don’t forget vegetables, like peas and beans, may need support too.

Later in the month, the spring bedding can be stripped out and composted. Tulip bulbs can be dried off in a shed and daffodils healed in a corner of the garden, or planted in natural lawn areas and borders.

Apply a preventative fungicide spray to roses and other plants before you see the diseases. Mildew and black spot will become evident soon. Look out too for aphids.