Gardens: It's time to freshen up borders After a slow start because of the very cold spring, we are emerging into a good flowering season. At the Botanics, the magnolias are now looking terrific, as are some of the late rhododendrons, and the tiny jewels in our Alpine House are a blaze of colour. In your own garden, now is a good time to freshen up the borders. Turn over the soil with a fork and apply bark mulch. If you haven't already done so, scarify and aerate your lawn. Scarifying removes moss, thatch and general debris that have built-up over the winter months. Aerating allows water, air and nutrients to reach the roots. Next, apply a nitrogen-rich fertiliser to feed and stimulate growth: if it doesn't rain within two or three days then water the lawn. Be sure to cut it weekly during the summer for a lush, green, lawn. The plants in your greenhouse are now likely to be requiring daily attention and you should be increasingly careful to shade plants to stop them getting scorched as the sun intensifies. Spray water on the path to help lower the air temperature and increase the humidity. Where possible, open ventilators or leave the door open during the day to increase air movement. This is a great month for sowing vegetables such as radishes, lettuces and turnips. Freshly-picked peas are a lovely treat but remember that early sowings will require staking by sticking in small canes or twigs alongside the shoots when they reach about 5cm in height. Similarly, any early potatoes already showing through already should be earthed-up using the loose soil around them to form a ridge. This helps them avoid being caught by late frosts and provides darkness to stop the ripening potatoes turning green. All your hard work will be well rewarded. Pete Brownless is garden supervisor, Royal Botanic Garden Edinburgh