April is the best month to apply a lawn fertiliser, just before rain - if it does not rain within 24 hours you will need to water the fertiliser in to avoid scorching the grass.

Apply lawn fertiliser

April is the best month to apply a lawn fertiliser, just before rain - if it does not rain within 24 hours you will need to water the fertiliser in to avoid scorching the grass. I apply a lawn feed, weed and moss-killer which tend to be quite expensive but do work. Lawn sand can be used to feed the lawn and reduce moss. It is less expensive but will not touch weeds. Unlike most things the cheapest brands are often as good as the expensive well-known brands.

Repotting houseplants

Many indoor plants will need to move up a pot size and will appreciate some fresh compost. Water them a day or two before repotting; tap them gently out of their old pots, supporting the plant with one hand. Do not be tempted to over-pot the plant as they tend to grow slowly, and use a good-quality potting compost - John Innes Number 3 would be suitable for most houseplants, or a peat-based compost. Put a layer of compost in the base, tapping the pot to settle it and put the plant in. If the plant is pot-bound, tease out the roots. Push more compost around the sides of the plant until it is 1-2.5cm from the rim. Water houseplants from the base so the compost is thoroughly soaked. When you see the top of the compost is moist after a few hours allow the excess to drain off.

Healthy eating...

Fruit trees and bushes will benefit from an application of general fertiliser. Pelleted poultry manure is good in the organic garden, but bonemeal or blood, fish and bone are all suitable feeds for fruit and ornamentals. Daphne mezereum, which will soon finish flowering, is a fine ornamental shrub that will benefit from a feed now, although don't prune it or move it as they can be very temperamental.

Spraying roses

Start spraying roses to prevent the build-up of black spot and mildew. Use a fungicide containing carbendazim applied every two weeks. Alternate this with a copper sulphate fungicide spray to prevent resistance building up. Roses need a good heavy soil with plenty of stable manure applied as a mulch - roses are surprisingly heavy feeders.

A well-known potato trick

I am preparing to plant my potato crop on the allotments. It is a well-known trick to plant early spuds late and late spuds early - it actually makes sense. What you need to do is plant early or new potatoes early, but if you plant them too early they will send up green lush new growth that then gets burnt off by the frost which will destroy young growth coming through the soil. Late or maincrop varieties should be planted early because they need a long growing season, and the sooner you can get them in the ground the more time the crop has to develop and grow. You only learn the best planting time from experience, but expect some frosts up to mid May which can damage the top of the plant so keep them earthed up well until then.

Preparing for spuds

Potatoes are heavy feeders and so prepare the soil well. Traditionally it would have been well manured in autumn. A generous application of a fertiliser - blood fish and bone or bonemeal or growmore - should be raked in at about 112g/m a few days before planting. Don't lime the soil, or plant in an area that has been limed in the last two years as it promotes potato scab. Try to cover the bed with a sheet of polythene for two weeks to warm it up, but remove it before planting. Dig a small trench 10cm deep and the length of the row. Place chatted seed potatoes 30cm apart in the trench with the sprouted eyes upwards, replace the soil carefully to avoid moving the potatoes. Space the rows 60cm apart to allow room for earthing up later.

Martyn Davey