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Lawn feeds and weeds

How to kill lawn weeds and moss

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How to kill lawn weeds and moss

Which? shows you how keep your lawn free of weeds and moss, plus how to feed your grass and keep it in top condition.


A weed-free lawn with no moss is an ideal that many gardeners would like to achieve, as the lush green turf makes the perfect backdrop to flower borders.

For small areas, removing weeds and moss is feasible, but for the the average lawn it's far easier to use a chemical lawn care treatment.

To discover the most effective treatments, head straight to our Best Buy lawn feeds, and lawn feeds, weeds and moss killers.

Tackling lawn weeds

You can dig out weeds by hand. Take care to remove all the root from perennial weeds such as dandelions, which will resprout if any root is left behind. Low-lying weeds can be weakened by raking them before mowing, so that the stems are raised and cut by the mower.

For turf with more widespread weeds, it's better to use a feed, weed and moss killer.

Dealing with moss

Although moss looks nice and green in winter, it dies back in summer, leaving unattractive brown patches. Dead moss accumulates as ‘thatch’ at the base of the grass, preventing air and water from reaching the grass roots. You can kill moss with a moss killer but, unless you treat the underlying cause, it will return.

The best way to discourage moss is to encourage the grass. Lawn grasses generally grow best on fertile, well-drained soil that gets plenty of sun. We found that it's best to feed your lawn four times a year, during the growing season. Drainage and soil aeration, particularly of compacted areas, can be improved by spiking with a garden fork to a depth of at least 7.5cm, or by hollow tining.

Lawn grasses grow most vigorously in open areas, and growth becomes weaker as shade increases. Densely shaded areas are never likely to support good lawn growth, and moss is likely to be a problem. If shade can’t be reduced, try thinning or removing overhanging trees.

Applying lawn-care treatments

Follow the instructions on the packaging carefully. Take particular note of the application rate and whether the product needs to be watered in. Some recommend repeated applications through the summer.

Some products are dissolved or diluted in water and applied using a watering can. Such products are best on smaller lawns. Make sure the granules are properly dissolved. Check what size area a full watering can will cover, and mark this out on the lawn using garden canes or similar. Walk up and down in one direction, spreading it as evenly as possible. Repeat at right angles until all the solution is used up.

Some products come in the form of granules that you spread by hand. If you have a large lawn, these are easier to apply using a lawn-fertiliser spreader. Check the product is suitable for the spreader and calibrate it to apply the granules at the correct rate.

If you apply granular products by hand, divide the lawn into equal areas. Work out how much of the product you need for that area, and weigh it into a plastic cup. You can then mark the cup so you apply the right amount to each area in turn. Scatter half the cup in one direction and the remainder at right angles to ensure an even distribution. If it doesn’t rain within 24 hours, you will need to water the lawn to wash the fertiliser into the soil. If possible, apply lawn feeds when rain is predicted.