May

Written by Julia Parker

May Greenhouse Growing Guide – Julia Parker

May heralds the beginning of summer, the days are warmer and longer, and it’s probably my favourite month, both in the vegetable patch and the main garden. Borders are full of bright green foliage and emerging flowers, namely peonies which are beginning to burst into flower along with camassia, geums, azaleas, wisteria and early roses.

It’s also a key time for growers deciding what to plant in May, with asparagus spears in full flow, early salads thriving, and first early potatoes ready to harvest by the end of the month. Rhubarb forcers can be thrown off allowing the edible stems to romp away all summer. Perennial and annual herbs will also be producing young fresh leaves ready for harvesting, and fruit will be swelling on trees and bushes after the last of the blossom.

What to plant in May: In the greenhouse

Heat loving crops i.e. tomatoes, cucumbers, melons, aubergines, peppers and chillies will all be ready for potting on or transplanting to their final resting place, be that grow bags, pots or beds. Once these plants start to flower give them a weekly feed and provide them with appropriate support in the form of canes and or string. There is still time to sow cucumbers and courgettes so don’t panic and looking ahead to autumn harvests, you can sow pumpkins and squashes in May. Sow annual herbs, such as basil, dill & coriander, basil is best planted near tomatoes to help keep white fly away.

Sow salad seeds every 6 weeks for a successional crop along with radishes, both can remain in the greenhouse to grow on or you can transplant them when big enough to handle to beds or borders outside. Start sowings of chard, beetroot, spinach, courgettes, sweetcorn and climbing beans and transplant outside next month.

Ventilate greenhouses on warm days but remember to close windows and vents at night when temperatures can drop.

TIP: Water early in the morning and try to keep water away from foliage this helps reduce fungal issues and mildew. On very hot days, water paths and flooring to keep the temperature cooler.

What to plant in May: In the vegetable garden

Plant out salads sown last month and regularly harvest asparagus spears every few days. Check peach, nectarine, apricot and almond trees for peach leaf curl and remove damaged leaves. Net gooseberries and blueberries.

Top dress citrus trees and switch to sing summer feed. Earth up first early growing potatoes in case there is a late frost, to protect the tubers below. Tie in climbing beans and keep beds weed free as much as you can, pulling the weeds up as soon as you see them helps as they are easier to remove at a young stage.

Check autumn sown broad beans for ripening pods, these mature first at the base of the stems, pinch out the growing tips when they reach 3 foot tall. Keep parsnip beds weed free and remove any overcrowded seedlings, if you haven’t sown them yet it’s your last chance to do so. Sow peas, carrots, beetroot directly outside along with french and runner beans by the end of May. Harden off pumpkins, courgettes and squashes seedlings by the end of the month.

TIP:Broad bean tips are edible, steam or stir fry, they taste like a mile broad bean.

What to plant in May: In the main garden

Stay on top of the weeding. Sweet peas should be planted out now with supports to climbing in place. Peonies will require stakes and ring support for heavy flower heads later. Check dahlias for new growth and protect as best you can from snails and slugs, try using wool pellets, ground coffee, egg shells or copper rings.

Plant out summer bedding, dead head spring bulbs and allow foliage to die back naturally. Mow lawns weekly and try to leave an area to grow wild for pollinators. Continue to sow hardy annuals such as nigella and cornflowers. If you have box plants growing in your garden check for box moth caterpillars and treat accordingly. You will never eradicate these pests but they can be controlled and managed.

TIP: Cut back herbaceous perennials in late May, coinciding with the Chelsea Flower Show this is known as the Chelsea Chop. It involves cutting back all or some of the stems to about one third to encourage bushier growth, more flowers and a better structure. Chives respond particularly well to this pruning method too.