Lawn care: watering, mowing, feeding and a month-by-month calendar

A good-looking lawn doesn't depend on a miracle product, but on doing three things well and consistently: mowing at the right height, watering deeply but rarely and feeding at the right time. Get those right and the grass thickens on its own, covers the gaps and leaves no room for weeds or moss. Add one scarification a year and top up the thin patches, and you'll have a lawn that's a pleasure to walk on barefoot.

This guide gets to the point: cutting height by season and why "mow lower to mow less often" is the most common mistake; how and when to really water; which fertiliser to use each season and how to apply it without scorching the grass; moss and weeds; and a month-by-month task calendar so you always know what's due. Ten FAQs at the end.

Mowing: the task that matters most

The golden rule is to never cut more than one third of the blade height in a single pass. If the lawn is 9 cm tall, don't go below 6. Cutting too short stresses the plant, exposes the soil (it dries out and weeds germinate) and forces the grass to spend its reserves regrowing instead of thickening the root.

In summer you raise the height because a longer blade shades its own base, keeps the soil cool and helps the root cope with drought. Keep the blades sharp: a blunt blade tears the tip instead of cutting it, and the lawn wakes up with white or brown tips the next day.

Leave the fine clippings on the lawn (mulching) whenever the grass isn't too tall or wet: they break down in a few days and return up to 25% of the nitrogen the lawn needs in a year. Only collect the clippings when the grass has grown too much and leaves "rows" that smother the base.

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Watering: few long soaks

A lawn needs between 3 and 6 litres per m² a week in spring and 25-35 litres per m² a week at the height of summer, rain included. What matters isn't just the amount but how you deliver it:

• Long, spaced-out soaks, not short daily ones. A soak that wets 15-20 cm deep makes the root go down looking for water; a short watering only wets the surface and creates a dependent lawn that yellows on the first hot day.
• At dawn (4:00-8:00). Watering during the day evaporates up to 30%; watering at dusk leaves the lawn wet all night and encourages fungi.
• The can test: place several glasses around the lawn, water for 15 minutes and measure the millimetres collected. That tells you how much your system applies and whether the spread is even.
• On clay soils or slopes, if the water runs off before it soaks in, split the watering into 2-3 short passes with half an hour between them.

To automate it properly, see the guide to automatic sprinklers and the one on smart WiFi irrigation, which adjusts watering to the actual weather.

Feeding: the timing matters more than the brand

Lawns consume mostly nitrogen (N), and they consume it spread over the growing season. A slow-release fertiliser releases the nitrogen gradually over 2-3 months, so 2-3 applications a year are enough:

Apply fertiliser with a spreader (never by hand: you get scorched strips and unfed patches), on a dry lawn, and water straight after so the granules reach the soil and don't burn the blade. Never feed during a heatwave or on dry soil.

Moss and weeds: symptoms, not diseases

Moss appears where the lawn is weak: shade, compacted soil, waterlogging, mowing too low or lack of feed. You can remove it with iron sulphate and rake it out, but if you don't fix the cause it comes back in two months. Aerate, raise the cutting height, improve drainage and feed: the lawn thickens and pushes the moss out on its own.

Weeds are the same: a dense, well-fed lawn barely leaves gaps for them to germinate. Pull the ones that do appear out by the root with a weeding tool when the soil is moist, before they flower and set seed.

Month-by-month task calendar

Quick glossary

• One-third rule: never cut more than a third of the leaf height in one mow, so as not to stress the plant.
• Mulching: leaving the fine clippings on the lawn so they break down and return nitrogen to the soil.
• Tillering: the grass sending up new shoots from the base; it's what thickens the lawn and closes gaps.
• Slow-release: fertiliser that releases nitrogen gradually over 2-3 months, rather than all at once.
• Scarifying: running vertical blades that pull out the thatch (layer of dead debris between the grass and the soil).
• Aerating: making holes in the soil to decompact it so air and water reach the root; different from scarifying.
• Top dressing: a thin layer of sand and sieved compost spread over the lawn to level it and add organic matter.
• Can test: placing several cups around the lawn and measuring the millimetres they collect to find out how much water the irrigation applies.

Frequently asked questions

Why is my lawn green but thin, with soil showing through?

Almost always mowing too low combined with too little feed. The grass spends its reserves regrowing and has none left to produce new side shoots (tillering). Raise the cutting height, feed in spring and autumn with slow-release, and overseed the bare patches: it thickens up in two months.

How often should I mow the lawn?

It depends on growth, not the calendar: mow when the grass has grown a third above your target height. In spring that's usually once a week; in summer, every 10-15 days; in winter, hardly at all.

Is it better to collect the clippings or leave them (mulching)?

Leave them whenever possible: fine clippings break down in days and provide free nitrogen. Only collect them if the grass has grown a lot and there are piles covering the base, or if there's a fungal disease and you don't want to spread it.

How much should I water the lawn in summer?

Between 25 and 35 litres per m² a week in the hottest areas, split into 2-3 long dawn soaks. Check with the can test and by digging: the day after watering, the soil should be moist to 15-20 cm.

Can I feed the lawn in summer?

Better not with high-nitrogen fertilisers: they force soft growth that suffers in the heat and uses water. If the colour is really flagging, a balanced slow-release feed in early June, and nothing else until September.

How do I get rid of moss in the lawn for good?

Moss is a symptom. You can remove it with iron sulphate and a rake, but it will return unless you fix the cause: aerate compacted soil, improve drainage where it waterlogs, raise the cutting height, reduce shade if you can, and feed so the lawn thickens and displaces it.

What's the ideal cutting height?

4-5 cm in spring and autumn, and 6-8 cm in summer. Never below 3 cm except on ornamental fine-grass lawns with intensive watering and feeding.

Why does the lawn yellow in stripes right after mowing?

Blunt blade (tears instead of cuts), mowing wet grass, or taking too much height off at once. Sharpen the blade, mow dry and never go below a third per pass.

Is a robot mower any good for lawn maintenance?

Yes, very much so: cutting a little every day means constant mulching and the lawn thickens. See the comparison in best robot lawn mowers and the debate in robot mower vs manual mower.

When do I stop mowing in winter?

When growth stops, usually in November. Do a last cut leaving the grass at about 5 cm (not too short, which gets cold, nor too long, which mats down in the damp) and store the mower clean with a sharp blade.

How many times a year should you feed a lawn?

With slow-release fertiliser, two or three: a high-nitrogen feed in March-April, a balanced one in June and a potassium-rich one in September-October. With fast-acting fertiliser you'd need more passes and the risk of scorching the leaf is higher. Never feed when the soil is dry or during a heatwave.

How do I get a greener lawn without feeding more?

Raise the cutting height slightly, leave the clippings (mulching), water deeply and spaced out rather than little and daily, and sharpen the blade for a clean cut. A one-off dose of iron (chelate or sulphate) intensifies the green in a few days without forcing growth. For full care of the area, see a patchy, dry or yellow lawn.

If you're starting from scratch or thickening a thin lawn, follow how to sow a lawn step by step, and to automate watering see smart WiFi irrigation.