- In the north, plant out summer vegetables and balcony plants.
- Stake tall perennials and tie in climbers.
- Mulch before the heat arrives.
- Hoe weeds while they're small.
- Water pots regularly.
Spotlight: a summer balcony that lasts into autumn
Balconies that look great in May and tired by July have usually run out of water and food, not luck. The first rule is to use the largest pots you can: more compost means a bigger water reserve and fewer emergencies on hot days.
Choose plants to suit the aspect. For full sun and south-facing balconies: pelargoniums, bougainvillea, lantana, mandevilla, plumbago and gazanias. For partial shade: busy lizzies, fuchsias and begonias. Climbers such as mandevilla need a small trellis from the start. Use a good-quality compost with a little sand or perlite, and mix in a slow-release fertiliser at planting time.
In summer water early in the morning until it runs out of the bottom – every day in hot weather – and from mid-June add a high-potash liquid feed every week or two. Deadhead regularly and, in July, cut back straggly stems for a second flush of flowers that carries on into October.
PelargoniumBougainvilleaLantanaMandevillaBusy lizzie Watering plants in pots ›
In your area
Plant out tomatoes, peppers, aubergines, courgettes and basil. Dahlias, coloured callas and balcony plants go outside. Thunderstorms and hail can arrive by the end of the month.
The whole summer vegetable garden is in; make second sowings of French beans and courgettes. On light soils, start watering regularly.
Olives and oleanders are in flower. Mulch every bed and the vegetable plot, install drip irrigation, and harvest broad beans, peas and the first courgettes. Lettuces bolt in the heat: sow them in the shade.
Jobs this month
Planting out and balconies
With nights now mild, tender plants can go outside in the north. Water them in well and keep an eye on them for the first week: a cold wind can scorch leaves even without frost.
Borders, hedges and shrubs
Perennials grow at their fastest in May: supports put in now disappear beneath the foliage, while those put in after a storm never look right.
Mulching and watering
A 5–7cm layer of mulch on moist soil halves the watering you'll need in summer. In the centre and south it should go down now, before the soil dries out deeply.
Pests
Pests multiply in the warmth, but most are brought under control by predators within a week or two. Check before you spray.
Sow and plant
- French beans, courgettes and cucumbers direct
- Lettuces and chard (in the shade in the south)
- Biennials: foxgloves and wallflowers
- Basil
- North: tomatoes, peppers, aubergines and courgettes
- Balcony and bedding annuals
- Dahlias, callas and cannas
- Herbs
Watch out for
Questions
When should courgettes be planted out?
When nights are above 12°C: April in the south, late April to May in the centre, May in the north. They can also be sown direct where they are to grow.
When should mulch go down?
On soil that is already warm and moist, in late spring: April–May in the south, May in the north. Laid on cold soil, it holds back growth.
Should I cut back daffodil leaves?
Only once they have turned yellow, about six weeks after flowering: the leaves are feeding next year's bulb.