Summer arrives
June 21 is the longest day of the year, and the associated extra light and warmth encourages the garden to put on an exuberant burst of growth. As a result, herbaceous borders are reaching their early summer peak and the kitchen garden is becoming productive.
The growing season is now most advanced in south-central and south-east England, taking over from the mild but slightly cooler south-west. Otherwise, average June condition arrive one to two weeks later in the Midlands, three weeks later in most of Wales and in areas just above Manchester. Unfortunately, these conditions take even longer to reach northern England and Scotland this month.
The strong sunshine means that gardeners need to hoe off weeds vigilantly and to keep new plants well watered.
Temperature
Afternoon temperatures can reach 27°C (80°F) in most parts of the country during June. This is particularly likely when there are few clouds in the sky, allowing the sun’s heat to easily reach the ground.
Daytime temperatures in southern England average 19°C (66°F), and there should be no frost at night. In the rest of England and Wales, the days are just a little cooler but, in Scotland, they average just 15°C (59°F). In these cold regions, there is still the outside chance of a frost so be prepared to cover tender plants with fleece when it’s forecast.
Ventilate conservatories and greenhouses in the daytime to prevent the sunshine causing inside temperatures to soar. Be ready use blinds if shading paints haven’t been applied to the glass. Prolonged warm spells will also accelerate the rate at which the soil dries out.
Rain
Periods of widespread rain are often brought by north westerly winds. In contrast, a south-west wind usually just brings drizzle to mountainous areas in north-west England and south-west Scotland. Occasionally, thunderstorms will rumble in, especially at the end of a fine period of weather.
June is one of the drier months of the year, particularly in southern and eastern England where less than 5cm (2in) fall on average. Higher rainfalls can be expected in south-west England, and an average of 8.5cm (3.5in) lands on gardens in Scotland and Wales.
This is generally not enough to keep soil thoroughly moist so, in most gardens, it will begin to dry out. In dry spells you may still need to water, particularly in south-east England and East Anglia. Don’t wait for plants to wilt before taking action and pay particular attention to new plantings and seed beds.
Wind
Light westerly winds cross the country, bringing generally cloudless conditions. There should be fewer gales than any other month, but it’s worth ensuring that herbaceous borders are well staked, just in case gusts flatten perennials.
Light
Plenty of strong sunshine will continue to ensure that plants grow rapidly this month. Levels vary across the country, but Scotland and Wales average around 160 hours of sunshine. In East Anglia and south-east England over 180 hours can be expected.