Lawn Feed Calculator

How Much Lawn Feed Do I Need?

This free lawn feed calculator tells you exactly how much feed your lawn needs based on its size and the product you're using. Select from popular UK lawn feed types — spring/summer, autumn/winter, weed & feed, moss killer — or enter a custom rate. Get results in grams, kilograms and pack counts instantly.

Getting the amount right matters. Too little and you won't see results. Too much and you'll scorch your lawn with brown patches that take weeks to recover.

Got bare patches that need reseeding? Use our grass seed calculator to work out how much seed you need.

Lawn Feed Application Rates

Different products need different rates. Use this guide with the calculator above.

How to Apply Lawn Feed Evenly

Using a spreader

A wheeled or handheld spreader gives the most even coverage. Set the aperture to the product's recommended setting. Walk at a steady pace, overlapping each pass by about 10cm. Apply half the product north-to-south, then the other half east-to-west for the most uniform result.

Applying by hand

If you don't have a spreader, divide your total feed into equal portions — one per strip of lawn about 1 metre wide. Scatter each portion evenly as you walk the strip. A level adult handful of granular feed is roughly 35–40g, which covers about 1 square metre at standard rate.

After applying

Water in thoroughly if rain isn't expected within 48 hours. Keep children and pets off the lawn until the feed has been watered in and the grass is dry. Don't mow for at least 3 days after feeding to give the product time to work.

Frequently Asked Questions

When to Apply Lawn Feed in the UK

Timing is everything with lawn feeding. Apply at the wrong time and you'll either waste product or damage your grass. Here's the month-by-month guide for UK lawns.

Top tip: Never feed a waterlogged, frozen, or drought-stressed lawn. The granules need moisture to dissolve into the soil, but standing water causes root damage. The sweet spot is moist soil with rain expected within 48 hours. Need to know what to plant this season? Check our UK planting calendar.

Common Lawn Feeding Mistakes

Even experienced gardeners make these mistakes. Getting them right can mean the difference between a bowling-green lawn and yellow, patchy grass.

1. Using too much feed

More is not better. Over-feeding causes fertiliser burn — brown or yellow stripes where the granules sat too long. The nitrogen salts draw moisture out of the grass blades, scorching them. If you've over-applied, soak the area immediately with a hose to dilute the feed. Always use the calculator above to measure the right amount.

2. Feeding in the wrong season

Spring feed in autumn (or vice versa) causes problems. High-nitrogen spring feed applied in September promotes soft, lush growth that can't survive frost. Autumn feed applied in spring doesn't provide enough nitrogen for the growing season. Always check the product label and match it to the season.

3. Applying on dry, hot days

Granular feed needs moisture to dissolve. Applied on a scorching July afternoon, it sits on the grass surface and burns. Feed in the evening or when rain is forecast within 48 hours. If no rain comes within 2 days, water in with a sprinkler or water butt.

4. Not measuring your lawn

Guessing your lawn size leads to under- or over-feeding. A 10m × 8m lawn is 80m² — at 35g/m², that's 2.8kg of feed. Without measuring, most people over-apply by 30–50%. Use the calculator at the top of this page to get the exact amount.

5. Mowing immediately after feeding

Wait at least 3 days after feeding before mowing. Cutting too soon removes the feed granules before they've dissolved into the soil. Some weed & feed products need 5–7 days to work on the weeds before mowing.

Lawn Feed Schedule — Month by Month UK Guide

Knowing when to feed is just as important as knowing how much to apply. UK lawns have a clear feeding cycle tied to the seasons, and getting the timing right means stronger roots, fewer weeds and a lawn that stays green from March to November. Here is the full month-by-month schedule.

March–April: Spring Feed

This is the most important feed of the year. Use a high-nitrogen spring feed (NPK around 14-2-5) to promote vigorous green growth after winter dormancy. Wait until the grass is actively growing — if it needs its first mow, it is ready for feeding. Soil temperature should be consistently above 5°C. In northern England and Scotland, this window often starts 2–3 weeks later than the south. Apply at 35g/m² and water in if rain is not forecast within 48 hours.

May–June: Summer Feed

Switch to a balanced NPK summer feed once the lawn is established and you have mowed at least twice at 25mm or above. This sustains growth through the main season without pushing excessive leaf production. Apply in the evening or on an overcast day to reduce the risk of scorch. If you are also dealing with broadleaf weeds, a weed & feed product works best during this window because the weeds are actively growing and absorb the herbicide more effectively.

July–August: Mid-Summer Caution

If the weather turns hot and dry, skip feeding entirely or use a liquid feed at half the recommended rate. Never feed drought-stressed grass — the nitrogen salts draw moisture out of already-struggling blades and cause severe scorching. If you want to maintain colour during a dry spell, iron sulphate at 4g/m² dissolved in water gives an instant green-up without stressing the roots. Resume normal feeding once rain returns and the grass starts growing again.

September–October: Autumn Feed

Switch to an autumn feed with high potassium and low nitrogen (NPK around 3-12-12). Potassium strengthens cell walls and hardens the grass against frost, disease and waterlogging. Low nitrogen prevents soft, lush growth that cannot survive winter. This is also the best time to overseed bare patches — feed first, wait 3 weeks, then sow seed. For general garden feeding at this time of year, our fertiliser calculator covers balanced and specialist fertiliser rates.

November–February: No Feeding

Grass is dormant through winter and cannot absorb nutrients. Any feed applied now washes straight through the soil and into waterways, wasting money and harming the environment. The only exception is a light application of iron sulphate in November to suppress moss and maintain colour, but this is optional — most lawns manage fine without it.

A word on overfeeding: Applying more than 4 feeds per year — or exceeding the recommended rate — causes thatch buildup. Thatch is a layer of dead organic matter between the grass blades and the soil surface. A thin layer (under 10mm) is normal, but thick thatch blocks water and air from reaching the roots, creating a weak lawn that is prone to disease and moss. If your lawn feels spongy underfoot, you likely have a thatch problem caused by overfeeding.

Granular vs Liquid Lawn Feed

Most UK garden centres stock both granular and liquid lawn feeds, and each has distinct advantages. Choosing the right format depends on your lawn size, how quickly you want results, and how often you are willing to reapply.

Granular lawn feed

Granular feeds are the most popular choice for UK lawns. They are easier to spread evenly — especially with a wheeled or handheld spreader — and most products are slow-release, meaning one application lasts 6–8 weeks. The granules dissolve gradually with rain or watering, delivering a steady supply of nutrients to the roots. The main downside is speed: you will not see results for 2–3 weeks. For large lawns over 50m², granular feed with a spreader is by far the most cost-effective and consistent option.

Liquid lawn feed

Liquid concentrates deliver nutrients directly to the grass blades and are absorbed almost immediately. You will typically see a greener lawn within 7–10 days — roughly half the wait compared to granular products. Liquid feeds also give more even coverage because there are no granules to clump or miss. The trade-off is that they need more frequent application (every 2–4 weeks versus 6–8 weeks for granular) and cost more per square metre on larger lawns. Liquid is ideal for small lawns under 30m² or as a quick colour boost between granular applications.

What about weed & feed products?

Weed & feed combines lawn fertiliser with a selective herbicide that kills broadleaf weeds (dandelions, clover, daisies) without harming grass. It is convenient but should only be applied where weeds are actually present — blanket-treating your entire lawn with herbicide when only one corner has dandelions is wasteful and puts unnecessary chemicals into your soil. For weed-free areas, use a standard lawn feed instead. Apply weed & feed between April and September when weeds are actively growing, and never use it on newly seeded or turfed lawns within the first 6 months.

Spring Lawn Feed Guide — March & April 2026

Spring is the most important feeding window of the year. Your lawn has been dormant for months and needs a nitrogen boost to kick-start growth. Here's how to get it right in the UK climate.

When to start spring feeding

Wait until your grass is actively growing — you'll see it needs its first mow of the year, usually mid-March to early April depending on your region. Northern England and Scotland typically start 2–3 weeks later than the south. The soil temperature needs to be consistently above 5°C for the grass roots to absorb nutrients. A good rule: if your lawn needs mowing, it's ready for feeding.

Which spring feed to choose

Use a high-nitrogen spring/summer lawn feed (NPK ratio around 14-2-5 or similar). The nitrogen drives leaf growth and that deep green colour. Avoid autumn feeds in spring — their high potassium and low nitrogen ratio won't give you the growth you need. If you have a moss problem, treat with a moss killer feed first, wait 2 weeks for the moss to blacken, rake it out, then apply your spring feed.

Spring feed + overseeding

Planning to overseed bare patches? Feed first, wait 3 weeks, then overseed. Or overseed first and wait until the new grass has been mowed twice before feeding. Never apply both on the same day — the fertiliser can burn young seedlings. Use our grass seed calculator to work out exactly how much seed you need for bare patches.

Starting a new lawn this spring?

If you are laying a new lawn from scratch, you will need at least 100mm of quality topsoil before seeding or turfing. Use our soil calculator to work out how much topsoil to order — getting the soil right before you feed gives you a lawn that actually holds nutrients instead of washing them away.

Lawn Feed vs Fertiliser — What's the Difference?

Many UK gardeners use these terms interchangeably, but they're not quite the same thing. Understanding the difference helps you choose the right product.

Lawn feed is formulated specifically for grass. It contains a balanced NPK ratio designed for turf — typically higher nitrogen for leaf growth, plus iron for colour and moss suppression. Products like Miracle-Gro EverGreen and Westland Aftercut are lawn feeds.

General fertiliser (like Growmore 7-7-7) is designed for all plants — vegetables, flowers, shrubs and lawns. It works on lawns but isn't optimised for them. The balanced NPK ratio means less nitrogen per gram compared to a dedicated lawn feed, so you'd need to apply more for the same result.

Which should you use? For lawns, always use a dedicated lawn feed. The application rates in the calculator above are based on products designed for turf. If you're feeding flower beds or vegetable plots, use our fertiliser calculator instead — it covers general-purpose fertilisers, organic feeds and specific nutrient ratios.

How Much Does Lawn Feed Cost in the UK? (2026 Prices)

Lawn feed is one of the cheapest ways to improve your garden, but prices vary wildly depending on what you buy and where. Here is what I actually pay for different products and how much they cost per application on a typical 80m² lawn.

The cheapest option by far is iron sulphate — under £2.50 to treat a full lawn. It does not feed the grass (no nitrogen), but it kills moss on contact and gives an instant deep green colour that lasts 4–6 weeks. I use it as a top-up between proper feeds.

For a full feeding programme — spring feed, summer top-up and autumn feed — budget around £12–16 per year for an 80m² lawn using the large-coverage products above. That works out at roughly 15–20p per square metre per year, which is less than most people spend on grass seed. If you have a larger lawn, buying the bigger packs brings the cost down further — some 800m² boxes cost only £30–35.

Spreader vs hand application

A wheeled spreader costs £25–40 and pays for itself on the first application if your lawn is over 50m². Hand-broadcasting granules inevitably leads to uneven coverage — heavy stripes where you overlap and bare patches where you miss. The scorch marks from over-application can take 4–6 weeks to recover, and by then you have missed the feeding window. I bought a basic wheeled spreader five years ago for £30 and it has saved me from at least three scorch incidents since. For lawns under 20m², a handheld shaker spreader at £8–12 works fine.

More Lawn Feed Questions Answered

Best Lawn Feeds UK 2026 — Our Top Picks

These are the lawn feeds UK gardeners actually buy and rate highest. We've matched each product to the right season so you know exactly which one to grab.

These are affiliate links — we may earn a small commission at no extra cost to you. We only recommend products we'd use on our own lawns.

Tired of Mowing? Go Robotic

If you're feeding a lawn over 200m², a robot mower pays for itself in time saved. These are the UK's top-rated models for 2026:

One sale of a Mammotion LUBA 2 saves you hundreds of hours of mowing. Links are affiliate links.