May is the time when it is beginning to warm up, spring is here and summer is on the way.
This is the season of vigorous growth in the garden – but watch out for cold snaps as you plant, sow and weed.
Most seeds sown now will germinate fairly quickly and frost tender plants can go out at the end of the month.
Don’t forget to take time out from the hard work to relax and enjoy your garden when the warmer weather arrives.
Want to know the secrets to handsome hanging baskets? Firstly, when you plant up, always use a good quality compost, an add some slow release fertiliser and water retaining crystals – they’ll make the baskets so much easier to care for come midsummer! You should also make sure you always plant up around the sides of the baskets, this will give more impact, quicker! Finally, through the season, keep taking off the dead flowers and you’ll get more and more grow on!
- Continue sowing annuals
- Support tall perennials in windy sites
- Harden off plants to be planted outside
- Pot on plants to be kept in containers
- Plant out hardy perennials and alpines grown from seed
- Trim alpines after flowering and propagate by division
- Put lilies grown in pots outdoors
- Plant out dahlias and chrysanthemums in late May
- Begin planting hanging baskets, tubs and containers
- Trim box hedging and topiary
- Feed roses and shrubs
- Plant dahlia tubers in borders outside
- Divide perennials that are congested
- Trim back winter flowering heathers
- Plant gladioli in groups outside
- Sow hardy annuals in any gaps in flower beds
- Prune forsythia after it has flowered and if you cut back Choisya after it has flowered it will promote a second flush of flowers in autumn.
- Check plants for signs of greenfly
In The Greenhouse
- Sow summer bedding
- Plant up hanging baskets and pots
- Pot up begonia and gloxinia tubers
- Hang up yellow sticky pest traps
- Open greenhouse vents on warm days and put up shading
- Check plants for pests and diseases
- Plant early crops in growing bags
- Sow seeds of melons in small pots
- Feed pot plants every week until autumn
- Take cuttings from chrysanthemums
- Repot established houseplants
- Sow Runner Beans either in cold frame or direct in your prepared bean trench
- Sow Sweetcorn in modules or toilet roll tubes in cold frame
- Sow French Beans directly into the soil
- Harden off Tomatoes and plant out at the end of the month in good rich soil
- Sow cucumber and gherkins in the cold frame or greenhouse
- Plant Brussels Sprouts – use the ground in between them for a catch crop of cauliflower or cabbage
- Sow succession crops such as lettuce, radish, rocket, spring onions, peas etc, every two weeks
- Thin Carrot and Beetroot sowings
- Net Strawberries against bird attack. To discourage slugs and protect fruit from mud splashes use pine needles instead of straw for mulch. It will keep the fruit clean and soil moist AND it gives the strawberries the slight acid edge they like AND slugs don’t like it.
- Keep Onions and Shallots free from weeds
- Sprinkle fertiliser around roses, shrubs and along the base of hedges
- Water newly planted trees and shrubs regularly, until they have established
- Hoe areas of bare soil on dry days to prevent weed seedlings taking hold
- Plant up aquatic baskets of new pond plants or water lilies
- Remove red lily beetles from lilies and fritillarias
- Pressure wash patios, paving and steps to remove slippery moss, slime and built-up dirt and grime