AS THE weather warms up, the grass will be growing – so you need to get rid of lumps, bumps and bald patches to ensure you have a carpet of green velvet in the months ahead.

A good-looking, healthy lawn not only makes the whole garden look tidy and provides a wonderful framework for colourful beds and borders, but it also helps encourage wildlife into the garden.

You should already have begun work on drainage and oxygenation, but it’s still not too late to scarify the lawn with a springtine rake to remove thatch – dead grass that mats beneath growing grass – and moss. For larger lawns, it’s worth renting a petrol driven lawn scarifier to do the same job.

If you have loads of moss, apply a moss killer before you scarify and wait a few days before raking it up, following instructions carefully.

Next, you need to improve badly draining soil by aerating the lawn, driving a garden fork into the ground all over the lawn when it is moist, making holes to a depth of 10-15cm (4-6in). I once bought a pair of lawn aerating shoes, but they were pretty cumbersome and kept falling off, so I went back to the fork.

Others use hollow-tine lawn aerators, which remove plugs of soil from the ground, but they are hard work and aren’t very good on stony soils or heavy, dry soils.

The holes you make allow air and water to get into the grass roots and should then be filled with a mixture of sharp sand and organic soil conditioner to stop the holes from closing up.

Feed the grass with lawn fertiliser available at most garden centres. This can be done by hand, applying aboutpproximately two grams per square metre, and water it in.

All lawns need good drainage and oxygenation. Some lawn dressings incorporate a slow-release fertiliser, but if this isn’t the case, add a little amount of general lawn fertiliser (not containing weed or moss killer) before applying it. Make sure you brush it evenly over the area or it will become patchy when the fertiliser kicks in.

A few weeks later, if your lawn is still patchy, oversow it lightly with a quality lawn seed.

Bumps in a lawn are a common problem. They’ll be regularly scalped by the mower and tend to become bare. To correct this, you may need to cut the turf at the area of the bump with a spade or an edging iron, peeling back the turf carefully and removing or adding soil as necessary to level the turf.

If the bump is prominent, you may need to remove some subsoil and replace topsoil, treading down the disturbed soil before firming back down the rolled-back turf after checking that the area is level, and filling the cracks with sifted soil.

You may feel your lawn is beyond repair if it’s weed and moss-ridden or full of bald patches. If two-thirds of the area is moss and weeds you may be better off starting again, turfing or seeding a new lawn.

But if you do decide that it’s worth saving, first cut it with the blades set quite high. If your grass is already long, give it a few cuts over a number of weeks, lowering the blades a little at a time, so that you cut the grass length down gradually.

By summer, you should be mowing weekly, stepping up to twice a week when necessary, but don’t mow the grass shorter than 2.5cm (1in) high and keep on top of weeds in the lawn.

Annual weeds that emerge in any bare patches will be removed by mowing.

Feeding should continue monthly through the summer, and in the autumn a high-potash fertiliser should be applied to keep grass luxuriant over the winter.

In dry weather, leave the clippings to shower and cool the surface, or a mulching mower can be used, which chops the cuttings up very finely and forces them back into the lawn where they provide valuable nutrients and help to prevent the turf drying out.

If it becomes necessary to water the lawn, avoid evaporation by watering in the early morning, late evening or using a timer at night. And even if watering does have to stop completely for a while and the lawn goes brown, it will recover once the rain comes.