Gardening Advice | May

Our resident plant expert, Phil McCann, shares his top tips as you head out into the garden this May..

Top May Gardening Tips:

  • Watch for Frost
  • Weed
  • Sow
  • Watch for Birds
  • Mow
  • Ventilate
  • Plant out
  • Lift daffodils
  • Plant out bulbs
  • Veg planting

Overview of May:

April had that spell of lovely warm weather and the plants loved it. Everything is growing so well now, including weeds, and lawns have never looked as good. So, it’s a month to buckle down and get things done. Where do we start? 


Watch for Frost:

The last dates for the chance of frost extend well into May for many so keep an eye on the weather forecast and have horticultural fleece handy to drape over susceptible plants and seedlings.



Same as last month and repeated next - keep on top of the weeds. Bittercress is a born survivor and tiny plants will flower and set seed. And then you’ve got a whole new generation of problems. Perennial weeds such as ground elder and bindweed don’t take long to take over. Hand weed removing roots or use a systemic weed killer to kill weeds straight to the root tips. Always read and act on the instructions when using chemicals. 



Short rows of vegetables are best, avoiding one massive glut and extending the cropping period. Sow a row / half row of carrots, wait a fortnight and sow another. Same with lettuce and radish. When sowing, cover the seeds with a quality compost - it marks where you’ve sown and helps you weed out the weeds and leave the crop.


Watch for Birds:

It's tempting to get all your hedges in good shape before any garden entertaining - but birds may well be nesting in there. Check by watching and observing before getting the hedge trimmers out. Shred hedge prunings and use in the compost bin. Shredded woody material helps balance out all those grass clippings currently stewing away.



Your lawn loves being cut. It’s actually a massive pruning exercise and the plants respond by growing stronger, squatter and healthier. Blades can be lowered now and a weekly mow is good. Twice weekly is fantastic. Only do this if the weather is dry and warm. Always clean the blades when you have finished (obviously take all safety precautions when doing this).



Greenhouses, even larger models, get hot quickly on a sunny day and plants can suffer. Fit an automatic vent opener if you are away all day and, on really hot days (we did have one in April if you remember), pour water onto the floor of the greenhouse. This helps reduce transpiration from the leaves. Doors can be left open, hooked safely, all day but always check for birds when you go to shut up shop for the evening.


Plant Out:

It depends on where you are in the UK but you could just plant out summer bedding plants, dahlias, potatoes (all the frost sensitive stuff) nearer to the end of the month. Warmer or protected gardens will be fine but exposed Northerly gardens may have to wait until June. Or - research your own locale and make that same decision with a little bit of expert knowledge.


Lift Daffodils:

Crowded bunches of daffodils eventually flower poorly so lift the whole lot, tease apart into smaller clumps and replant elsewhere in the garden. This will invigorate every plant in the clump, resulting in a better spring display. All you need is a garden fork and a little bit of time. And a trowel to replant.


Plant out bulbs:

Bulbs that have flowered in pots can either be left in a quiet part of the garden to die down, have a snooze and then regrow and flower next year (hyacinths, fritillaries, muscari and tulips all spring to mind) or you can knock them out of the pots and plant, at the same depth they were growing in a container, into the garden. They’ll still die down etc but will flower in your beds and borders next year. It will also release plenty of pots for more summer bedding.


Veg Planting:

Hardened off seedlings of celery, artichokes, sweetcorn and squashes can all be planted out into soil warmed by the sun and helped even more by cloches. I do worry about the frost so be prepared - but celeriac and celery need long growing seasons so need an early planting.