How to Apply Lawn Fertiliser Properly for Professional Results in the UK

The best results come from using a fertiliser that is formulated specifically for the current season.

Different times of year require different nutrient balances. A one-size-fits-all product cannot provide the same level of targeted support.

Our seasonal range was developed through years of professional lawn care experience and is designed to work as a complete programme throughout the year. When used consistently, it builds stronger roots, more even colour and better resilience.

• Spring Surge Pro supports recovery and early growth.
• Summer Boost Pro provides steady feeding during heat and dry spells.
• Autumn Guard Pro focuses on strengthening roots before winter.
• Winter Shield Pro helps maintain colour and resilience in colder conditions.

Apply lawn fertiliser when the grass is actively growing and soil temperatures are above 8°C.

The lawn should be frost-free and not waterlogged. Avoid applying just before heavy downpours. Light rain within 1–2 days is ideal, as it helps move nutrients into the soil.

All Johnson Lawn Care Direct fertilisers are applied at 23–25 grams per square metre.

Although this may not look like a large amount, it is precisely the correct rate for professional-grade fertiliser. More does not mean better. Careful measurement ensures safe, consistent results and helps you get the full benefit from each bag.

If you are unsure of your lawn size, use our online measuring tool before you begin.

As a guide:

• 50m² lawn = 1.25kg
• 100m² lawn = 2.5kg
• 200m² lawn = 5kg
• 300m² lawn = 7.5kg
• 400m² lawn = 10kg
• 500m² lawn = 12.5kg
• 1000m² lawn = 25kg

Applying more will not improve results and increases the risk of overfeeding. Measuring accurately is key.

For a strong, healthy lawn, fertiliser should be applied every 10–12 weeks using a product designed for the current season.

Lawns have different needs throughout the year. Spring feeding supports recovery and growth, summer feeding helps the lawn cope with heat and stress, autumn feeding strengthens roots, and winter feeding maintains condition during colder months.

Feeding seasonally and consistently is what builds long-term lawn health.

Many customers choose our auto-delivery option so the correct seasonal fertiliser arrives automatically every 3 months. It takes the guesswork out of timing and ensures the lawn is always supported at the right stage of growth. For more information, see our Fertiliser Range.

The safest and most effective way to apply lawn fertiliser is to measure carefully and spread evenly at 23–25g per square metre.

Professional-grade fertilisers are more concentrated than typical shop products. Accuracy is important. Applying more will not improve results and may cause damage.

Using a handheld or broadcast spreader makes it much easier to achieve an even finish. If you do not already have one, our Handheld Fertiliser Spreader is designed specifically to deliver the correct application rate.

When applied correctly and at the right time of year, seasonal feeding produces visible improvement within days.

Yes, but extra care is needed.

Measure the full amount out before you begin and wear gloves. Familiarise yourself with what 25g per square metre looks like, then spread small amounts evenly as you walk to avoid over-application in one area. Uneven hand application is the most common cause of dark patches or scorch.

A spreader provides more consistent results.

The most reliable method is to use a spreader and apply in two passes at right angles to each other.

This helps prevent missed strips and overlapping areas.

Before applying to the whole lawn, you can calibrate your spreader by testing on a measured 10m² area to ensure the correct rate.

Yes. Our Spring, Autumn and Winter fertilisers must be watered in within 1–2 days of application. Watering moves the nutrients into the soil and down to the root zone where they are needed. If left sitting on the leaf during warm or dry conditions, concentrated nutrients can cause the grass to scorch, resulting in brown patches.

Summer Boost Pro works differently.

It contains a technologically advanced moisture-responsive nitrogen coating. Unlike conventional fertilisers that begin releasing immediately, this coating responds to moisture and temperature. Feeding begins only when moisture returns.

This means Summer Boost Pro can safely be applied during dry spells and even during hosepipe bans without the same risk of scorch. When rain arrives, feeding begins naturally.

If you are able to water during dry conditions, results will always be enhanced. However, the formulation is specifically designed to provide greater flexibility and safety during summer stress.

In active growing conditions, you can usually expect visible improvement within 7–10 days.

Cooler temperatures or low moisture may slow visible results slightly. Fertiliser also supports root development beneath the surface, which may not be immediately visible.

Avoid mowing for 1-2 day before application and 2–3 days after application to allow the fertiliser to settle and begin working.

All of our fertilisers are safe for children and pets to walk on once it has been watered in and the grass is dry. We do not recommend grazing pets are allowed to digest the grass for at least 4 weeks. For more information, see our Children & Pet Safety Guide.

Most issues arise from over-application, uneven spreading or incorrect timing.

Measure carefully. Apply evenly. Follow seasonal timing.

Professional-grade fertiliser works extremely well when used correctly. Feeding little and often, in line with the seasons, produces far better long-term results than occasional heavy applications.

That is why our fertilisers are designed as a year-round programme rather than a single treatment.