What to do in your garden in May

What to do in your garden - May

After taking time to relax after Easter it’s now time to carry on with the gardening. What’s more, May is the month that kicks up a gear as vegetable and flower plants can be planted outdoors into their final growing, weather conditions allowing of course. It is also good to be able to start taking care of lawns to get that appearance we love so much! Now that the soil should start to warm up, with weeds sprouting, it’s the perfect time for sowing seeds such as primrose, sweet william, cauliflower, spinach and radish. However, keep an eye on any weeds appearing as they will need taking in hand!

phoenix grape vine plant


  • Keep well watered in dry spells to ensure good setting and fruit development.
  • For more growth on grape vines, pinch out the tips of shoots that are two leaves beyond a developing fruit truss.
  • Rhubarb stems that have been forced under jars can be harvested by gripping them firmly at the base, then pulling them sharply away from the crown.
  • To keep fruit clean and discourage mould lay straw between strawberry plants.


  • Provided the weather is mild and the grass is growing, applications of lawn fertilisers and weed killers can be made to established lawns.
  • Depending on growth, regular mowings with the blades set at maximum height may be necessary, remembering to remove any dead foliage beforehand.
  • This is the time to control fairy ring, also yorkshire fog, couch weed, bindweed along with other weeds being eradicated by teasing them out and cutting the roots.
  • Continue to sow new lawns.


  • Beetroot and spinach can be thinned out at this time.
  • Earth up potatoes by using a hoe to pull up the soil when they are approximately 23cm (9″) high.
  • For extra support use a hoe to place soil up around the base of the stems of broad beans.
  • If weather conditions allow, runner and french beans raised under glass can be planted out towards the end of the month.
  • Seeds could also be sown outdoors at this time under cloches. However, for an early crop sow two seeds per deep pot in the greenhouse or on a windowsill, thinning out to leave the strongest seedling for planting outside in late May or June.
  • Marrow, courgette and sweet corn should be sown in the greenhouse and also outdoors at the end of the month, into early June.
  • There are also a number of other subjects which may be sown either outside or under cloches during early May including broccoli, brussels sprouts, cauliflower, kale, peas, lettuce, radish, spinach and swede.
  • Baby vegetables (see our Speedy Veg Seeds section) are becoming very popular especially where space is limited. Many can be sown at this time and, with the exception of sweet corn, can be grown in containers and growbags on the patio as well as in the vegetable garden. However, should soil conditions be cold and wet, delay sowing.

Hanging Baskets / Patio Containers

  • As long as your patio is sheltered or under cover, hanging baskets/containers can be planted up with fuchsias and tender perennials.
  • Why not incorporate a slow release fertiliser and water storing crystals to reduce feeding and help water retention at the same time but remember not to place outside until the end of May/early June so that containers do not dry out. Watering can be stepped up on warm, breezy days.
  • Dwarf dahlias can be potted up into containers ready to provide colour from mid summer to early autumn.
water storing crystals


  • If soil conditions are not too wet, dahlia tubers can be planted direct into the garden soil from early May onwards for late summer flowering. Gladioli can also be planted at this time directly outdoors for late flowering.
  • Provided the risk of late frosts have passed, tender summer bedding plants can be planted outdoors towards the end of the month, but if weather conditions are still wet and cold delay planting until early next month.
  • Taller perennials or those subjects which may tend to fall over will require the support of frames.
  • The sowing of hardy annual flowers should now be completed, however, later sowings will result in the plants flowering later.
  • You may find it worthwhile with some plants, such as fuchsias, to remove the very tip of a shoot which will then encourage them to branch out.
  • Nasturtium seed couldn’t be easier to sow, just push it into damp compost.
  • It is always a good idea to regularly check your plants making sure they receive sufficient water and do not dry out.
  • It is also a good idea to commence weekly liquid feeds which will prove beneficial and to re-pot any plants that show signs of becoming root-bound.
  • As pansy flowers wither remember to dead-head them to encourage further flowering.
  • Now is also a good time to check for greenfly especially on spring bedding and bulbs such as daffodils and tulips.
  • During early May chrysanthemums raised from cuttings can be planted out along with a tall cane for support as the plants grow.


  • Should weather conditions still seem uncertain, take precautions to guard against frost especially at night by placing garden fleece over emerging crops such as potatoes, covering cold frames with either polythene or sacking, and young plants that are in the greenhouse can be covered with newspaper.
  • Prevent weed seedlings from becoming established by hoeing borders once a week.
  • Any plants being delivered this month must be opened immediately, if not, the leaves will go yellow with rot setting in.
  • Remember, if you are going to be away, make arrangements for them to be delivered to a friend so that they can still be opened up.
  • Many plants are susceptible to attack by aphids and measures should be taken to bring this common pest under control.
  • Vine weevil can sometimes cause quite a problem so it may be an idea to use a biological nematode – simply mix into a solution and water plants when larvae are active (soil temperature should approximately be above 5ºC/40ºF).
  • To keep control of slugs and snails, trap them under tiles or even grapefruit skins remembering to collect them up and disposing of them. There are also non-chemical traps available such as Slug Umbrellas and Nemaslug Slug Killer – use pellets only sparingly.
fleece provides great protection for all sorts of garden/allotment plants


  • Water lilies and other pond plants can be planted up in new aquatic baskets and compost, do not use ordinary compost as it encourages algae and is too rich.
  • Any plants that have become overcrowded should be lifted and divided, trimming any stray roots and this procedure should be carried out every few years.
  • If you have a new pond, let it settle for at least six weeks before adding fish.
  • When the water reaches 10ºC (50ºF) start to feed fish but remove any uneaten food after about 10 minutes.
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