May can be a seductive month with longer days, higher temperatures and hopefully enough warm sunshine. It’s the month to begin planting and sowing outdoors in earnest, however only transplant tender seedlings when the last chance of frost has gone. Harden off any plants grown indoors before planting out and be aware of the possibility of a night time attack from slugs.
Move seedlings grown under cover outdoors in the daytime to enable them to adjust to outside temperatures.
Continue to earth up rows of potato plants to ensure tubers underground are not exposed to light
Cover strawberry plants with cloches overnight for an early crop. Remove cloches during the day
Sow outdoors if the weather is mild
Protect tender plants against sudden frosts, keep an eye on the weather forecast and be ready with cloches and fleece
Weed regularly and thoroughly and keep young plants well-watered
Net fruit bushes to protect them from birds
Brussels sprouts, summer, autumn and red cabbage plants and cauliflowers – all these plants grow quite large therefore space out well across the plot, don’t crowd them
Celery – begin planting out this month
Courgettes, marrows, pumpkins and squashes – plant out in soil that has been enriched with plenty of organic matter.
Globe artichokes – this month is your last chance for propagating artichokes by dividing and taking offsets from established plants
Leeks – May is normally the first month to start transplanting out leek plants
Sweetcorn – start planting out, plant in blocks – if you’re struggling for space you could adopt an old Native American styled system of the Three Sisters – blocks of corn with climbing beans planted at their base and courgette/marrow /pumpkin planted in between.
Continue with successional sowing of most vegetables and salad crops
Tie in new shoots on Autumn raspberries
Apply mulch to discourage weeds and retain moisture
Plant out seedlings from your cold frame once frost danger has passed, i.e. towards the end of the month.
Tie in sweet peas as they grow
Watch out for pests on fruit
Apples – Codling moth pheromone traps should be put up the middle of May.
Plums – Plum moth pheromone traps should be put up the beginning of May.
Still very cold at the moment but shade your greenhouse on hot days and/or leave the door open or your plants will fry in the heat.
Straw strawberries, put straw, cardboard or polythene under plants to keep them off the soil.