Complete Guide to Feeding your lawn
A healthy lawn doesn't happen by chance. Every time you mow, your grass uses valuable nutrients to produce new growth, repair damage and maintain its rich green colour. Over time these nutrients become depleted, which is why regular feeding is one of the most important parts of lawn care.
Whether you're establishing a new lawn from seed or maintaining an established garden lawn, understanding how fertilisers work will help you choose the right product and apply it at the right time.
Why Feed Your Lawn?
Like all plants, grass requires frequent feeding to be at it's best. Grass especially is constantly growing, producing new leaves and roots while recovering from mowing, foot traffic and changing weather. To support this growth, it requires a steady supply of essential nutrients.
By feeding your lawn correctly you will get a deeper, richer green colour in your lawn, as well as more dense growth (crowding out and naturally suppressing weeds). Your lawn will also recover faster from wear and heat damage, develop stronger roots and have better resistance against drought, heat and turf diseases.
Without regular feeding lawns can become pale, thin and weak.
Not Every Lawn Needs the Same Amount of Fertiliser
One of the biggest misconceptions is that every lawn should be fed heavily throughout the year. The amount of fertiliser required depends largely on the type of grasses growing in your lawn.
Lawns containing a high proportion of fine fescues naturally grow more slowly and generally require much less fertiliser. Excess feeding can actually reduce their performance and encourage coarser grasses to dominate.
By comparison, lawns containing perennial ryegrass or bent grasses are more vigorous and often benefit from a more regular feeding programme, particularly where the lawn experiences frequent use. This is one reason why professional sports turf receives far more fertiliser than a typical domestic lawn. It is under significantly greater stress and expected to perform to a much higher standard.
Understanding NPK
Every lawn fertiliser contains a combination of three primary nutrients, known collectively as NPK.
Nitrogen (N)
Nitrogen is the nutrient most responsible for visible lawn growth.
Effect on lawn:
- Rich green colour
- Faster leaf growth
- Improved recovery after mowing
- Greater shoot density
- Better wear tolerance
Nitrogen deficiencies often appear as pale green or yellowing grass and reduced growth. Excessive nitrogen, however, can produce soft growth that requires more mowing and may become more susceptible to disease.
Typical sources: Ammonium sulphate (21% N), Ammonium nitrate (35% N), Potassium nitrate (13% N), Isobutylidene (32% N), Urea formaldehyde (40% N), Sodium nitrate (16% N), Potassium nitrate (15% N), Hooves & Horns (13% N) & Dried blood (10-14% N)
Recognising nitrogen deficiency: Yellowing older leaves, closely followed by yellowing of entire plant and slow growth.
Phosphorus (P)
Phosphorus is primarily responsible for establishing healthy root systems.
Effect on lawn:
- Supports seed germination
- Better Root development
- Strong early establishment
- Energy transfer within the plant
Young lawns benefit most from phosphorus, while established lawns generally require lower levels.
Typical sources: Superphosphate (19% P), Triplesuperphosphate (47% P), Ammonium phosphate (50% P) & Bone Meal (22% P)
Recognising phosphorus deficiency: Older leaves become unusually dark green before discolouring to purple on leaf edges.
Potassium (K)
Potassium acts as the lawn's natural defence system.
Effect on lawn:
- Improved drought tolerance
- Improved disease resistance
- Improved winter hardiness
- Improved water regulation
- Improved overall plant strength
Autumn lawn feeds usually contain increased potassium levels to prepare grass for winter conditions.
Typical sources: Potassium chloride (60% K) & Potassium sulphate (50% K)
Recognising potassium deficiency: Browning around leaf tips and plant begins to dry up. Possible excessive amounts of new growth.
Secondary Lawn Feed Nutrients
While NPK receives most attention, grass also relies on several secondary nutrients.
Calcium (Ca)
Calcium helps strengthen plant cell walls, improving structural strength and supporting healthy root growth.
Typical sources: -
Recognising calcium deficiency: Very uncommon, but when present in young leaves they turn red-brown colour. Likely to turn fully red if deficiency left untreated.
Magnesium (Mg)
Magnesium is an essential part of chlorophyll, making it critical for photosynthesis and maintaining a healthy green colour.
Typical sources: Magnesium sulphate (10% Mg), Kieserite (27% Mg), Dolomitic limestone (11% Mg) & Epsom salts (17% Mg)
Recognising magnesium deficiency: Older leaves will exhibit a red discolouration. Necrosis (browning/death to some or all of the plant) will appear if untreated.
Sulphur (S)
Sulphur supports protein production and helps grass efficiently utilise nitrogen.
Typical sources: Unlikely to be used as a single nurient
Recognising sulphur deficiency: Rare but leaves will turn a pale yellow while the leaf tip & edge turns brown or appears burnt.
Iron (Fe)
Iron enhances lawn colour without encouraging excessive growth. It is widely used in lawn treatments because it produces a darker green colour, helps discourage moss, improves visual appearance & supports chlorophyll production
Typical sources: Ferrous sulphate (20% Fe) & Ferrous oxalate (30% Fe)
Recognising iron deficiency: Interveinal (between the leaf veins running up the leaf) yellowing on the grass leaf. Slower growth of the plant.
Feed Application Based on Soil Type & Seasons
Your soil has a major influence on how often fertiliser is needed.
Soil Type |
Suggested Feed Frequency |
| Very Sandy | Two to four light applications. |
| Silt Loam | One or two light applications. |
| Clay Loam | One or two light applications. |
| Organic | One or two light applications. |
To find out what soil your lawn is simply carry out a hand test & compare to soil characteristics - Soil identification page coming soon...
For feeding throughout the year, we only look at 3 of the seasons. In winter you are unlikely to feed your lawn & have any grass growth. The 3 feeding regimes:
Spring Feeding
As soil temperatures begin to rise and grass starts actively growing, a spring fertiliser provides the nutrients needed to kick-start the growing season.
Spring feeds are usually higher in nitrogen to encourage fresh green growth.
However, avoid feeding while the lawn is still dormant. Grass should already be actively growing before fertiliser is applied, otherwise nutrients cannot be efficiently absorbed.
Summer Feeding
Nitrogen remains important throughout summer because the lawn continues producing new leaves.
If your lawn receives regular family use or heavy wear, a summer application can help maintain colour and density.
Avoid applying fertiliser during prolonged hot, dry weather unless irrigation is available.
Too much nitrogen during summer can also encourage excessive leaf growth at the expense of root development.
Autumn Feeding
As temperatures cool, the lawn prepares for winter. Autumn fertilisers reduce nitrogen levels while increasing potassium.
This encourages:
- Stronger roots
- Improved disease resistance
- Better winter survival
- Reduced risk of soft frost-damaged growth
How to Choose Your Lawn Feed?
Lawn feeds tend to come in 2 forms; Granular & Liquid
Granular fertilisers are the most popular choice for home lawns because they provide longer-lasting nutrition and are easy to spread evenly.
Liquid fertilisers provide a rapid colour response and are often used by professional grounds teams for fine-tuning turf appearance, but generally require more frequent applications.
Other factors to consider include the feed's nutrient release, which cmes in 3 different options:
- Quick Release - Nutrient released over short period
- Slow Release - Nutrient released over a 3 - 6 month period
- Controlled Release - Nutrient released in a controlled manner generally over a long period of time. Control can be through temperature or moisture.
Quick Release vs Slow Release
| Feature | Quick Release | Slow Release |
| Response Time | Rapid | Gradual |
| Duration | Days to Weeks | Several Weeks to 6 Months |
| Growth Pattern | Fast Flushes | Even & Consistent Growth |
| Burn Risk | High | Low |
| Cost | Low | High |
| Best for | Fast Recovery | Long-term Lawn Health |
How to Apply Lawn Feed/Fertiliser
Applying lawn fertiliser correctly is just as important as choosing the right product. Applying too little may not give your lawn the nutrients it needs, while applying too much can lead to excessive growth, wasted product or even scorch the grass.
Follow these simple steps for the best results.
For fertiliser to work effectively, the grass needs to be actively growing. The ideal conditions are; soil temperatures above 8–10°C, A dry lawn before application, rain forecast within the next 24–48 hours (or the ability to water afterwards) & mild weather without extreme heat or frost
You want to avoid feeding during prolonged drought or frozen ground temps, as well as immediately before heavy rainfall, as nutrients can be washed away.
Mow your lawn one or two days before applying fertiliser. This allows the granules to reach the soil surface rather than sitting on long grass leaves.
Avoid mowing immediately after applying lawn feed. Give the fertiliser time to be absorbed first.
Always follow the application rate shown on the product packaging. Applying more fertiliser won't produce a better lawn - it simply increases the risk of scorching and unnecessary nutrient loss. Using the correct rate ensures your lawn receives a balanced supply of nutrients while protecting the environment.
Even coverage is essential for consistent colour and growth.
The easiest way to achieve this is by using a lawn spreader, for the granular feeds, which distributes fertiliser evenly across the lawn. For larger lawns, a wheeled broadcast or drop spreader is ideal. Smaller lawns can be treated using a handheld spreader. If spreading by hand, walk at a steady pace and overlap each pass slightly to avoid stripes or missed areas.
Most granular lawn feeds should be watered in after application unless rainfall is expected shortly afterwards.
Watering helps:
- Wash granules off the grass leaves
- Move nutrients into the soil
- Reduce the risk of leaf scorch
- Begin the nutrient release process
If heavy rain is forecast, it's usually better to wait, as excessive rainfall can wash nutrients beyond the root zone before the lawn has a chance to absorb them.
Once fertiliser has been watered into the soil and the lawn has dried, it can usually be used as normal. Until then:
- Keep children and pets off the lawn - especially if fertiliser chosen has harmful chemicals.
- Avoid brushing against wet fertiliser granules.
- Sweep up any fertiliser that lands on paths, patios or driveways to prevent staining and nutrient runoff.
Always follow any specific safety advice provided on the product label.
Stay Green - All Year Round
A winning lawn starts here - Ace Lawn has drought resistant Microclover, meaning your lawn stays green all year round.