RHS top gardening tips - Telegraph In mild areas, plant early potatoes. Once shoots appear, earth them up but be prepared to cover any exposed growth to protect against frost. In colder regions, wait until April to plant. If you have a greenhouse, sow sweet peppers, tomatoes, cucumbers, aubergines and celery. Good results can be achieved using a heated propagator on a well-lit window sill, but delay sowings until the end of the month. 3 Blueberries fruit best on wood up to about four years old. On established bushes, prune out a few older stems from the base, plus any spindly growth. Also cut back shoots growing horizontally at the base of the plant. 4 Nitrogen is in a short supply in soils at this time of year. Ground used for intensive crops, such as fruit and vegetables, will benefit from additional feeding. Growmore is a cost-effective general fertiliser but organic gardeners may prefer pelleted chicken manure. 5 Barley straw can be useful in reducing the growth of algae in ponds, but it needs to be put in place now to be effective. It is readily available from pet stores, where it is sold as animal bedding. Place in the pond margins in large net bags with a couple of bricks. 6 Most gardeners either overlook feeding bulbs or feed too late, when they are in bloom. If not done already, apply a high potassium fertiliser to emerging bulbs. 7 Sow fresh seed of parsnips in clusters of five seeds 6in apart, to ensure there are no gaps in the rows of this slow-to-germinate vegetable. Thin them out later. Other slowly maturing vegetables, such as leeks and Brussels sprouts, should also be sown now. 8 Hard-prune dogwoods and willows grown for their bark colour to get bright, young stems for next winter. This is also a good time to renovate old camellias by cutting back to a framework of main branches.