Fertilising your lawn can be confusing.
One cause for confusion is the type of lawn fertiliser you should use. Should you use a liquid lawn food or a granular fertiliser?
The simple answer is to use both.
I’m going to explain when to feed your lawn with one over the other as well as how to use them together throughout the year.
The Differences Between Granular and Liquid Lawn Food
It helps to understand the difference between each type of fertiliser as that will provide more insight into how to use them and when.
Granular Lawn Feed
Granular fertilisers release their nutrients slowly over time as the granules within the feed break down into the soil.
Most of these products release their nutrients over the course of 10-12 weeks although some work faster and some take longer.
You can apply granular feed by hand which is fine for small lawns, however hand spreading becomes much less accurate over larger lawns. Its best to use a lawn spreader in these instances.
Moisture and water in the soil activates the fertiliser so that nutrients are consumed by the grass via its roots, prompting growth and greening of the leaf.
Liquid Lawn Food
Liquid lawn feeds usually act much faster at an average of 2-4 weeks.
They’re usually mixed with water and can be applied via a watering can or a knapsack sprayer.
These nutrients enter the grass plants via the leaf instead of the roots which causes faster growth and greening of the lawn at a faster rate than granular feeds.
How to Use Granular and Liquid Fertilisers
Many gardeners decide to use one type of fertiliser over another. In order to achieve the best results, gardening and lawn care professionals use both.
Granular feeds are used for ‘base feeding’ whereas liquid feeds are used for ‘demand feeding’.
Base Feeding with Granular Lawn Fertiliser
Granular fertilisers are generally applied 4 times a year for domestic lawns. Once in spring, summer autumn and winter.
These products should be applied routinely as they feed your lawn over a period of weeks.
Demand Feeding with Liquid Fertiliser
Demand feeding is used when your lawn needs a nutrient boost. This stimulates growth and greening of the leaf.
The nitrogen content is usually very high in liquid feed, so you need to be careful with how much you apply to your lawn.
Other Types of Lawn Food and How to Use Them
It isn’t just dedicated fertilisers that come in liquid or granular based products.
Lawn Weed and Feed
Lawn weed and feed products are marketed as ‘all in one’ products. They are sold as being designed to save you time and money.
They’re available as both granular products like Evergreen 4-in-1 Complete or in liquid form like Vitax Green Up.
They are designed to be applied once or twice a year, varying by product.
These products save time because they kill moss and broad-leafed weeds while feeding the lawn at the same time. They also save money because instead of buying a separate moss killer, a fertiliser and a weed killer, you have all three components in one product.
Iron Sulphate
Most lawn fertilisers contain Nitrogen (N), Potassium (P) and Phosphate (K) as these are the building blocks of lawn growth. But there are other elements that your grass needs in small amounts. These include:
- Molybdenum
- Boron
- Copper
- Chlorine
- Zinc
- Magnesium
- Iron
Most soils contain these elements with only the poorest soil lacking them. Iron is usually the element in the shortest supply.
Iron Sulphate (or Ferrous Sulphate) not only kills moss, but it’s also a component of chlorophyll which is what makes your grass green.
Applying a dose during the winter limits moss growth, will give your grass a boost of green colour and also protects the grass against poor weather and the cold and wet.
It comes in a powder form which you mix with water and apply as a liquid.
You should use ferrous sulphate with caution as it can permanently stain patios, pathways and driveways. Some fertiliser manufacturers add it to their weed and feed products to give the grass a further boost of green colouring, so be careful when using them near paved areas and garden furniture.
Which Type of Lawn Food Should You Use?
The simple answer is that it depends on your enthusiasm for gardening.
If You Don’t Like Gardening
If you would rather spend as little time gardening as possible, use a weed and feed product.
Evergreen 4-in-1 Complete can be applied twice a year. Once in the spring and once in the autumn.
Vitax Green Up feed is designed to be used once a year
Do note that these products are designed to keep on top of weeds and moss. If your garden is overrun with weeds, moss or thatch, they will not help.
You will first need to rake away the moss and discard it, scarify the lawn to remove excess lawn thatch and aerate your lawn to improve the penetration of water, oxygen and nutrients into the soil.
If You’re a Gardening Enthusiast
If you enjoy spending time in the garden maintaining your lawn, then apply a granular base feed every season.
A product like Scotts Spring / Summer Lawn Builder can be applied in April and July. Scotts Autumn / Winter Lawn Builder can be applied in September and January.
If You’re After Perfection
Apply a granular base feed to your lawn once a season.
If your lawn looks a little tired during the spring or summer, apply a dose of liquid feed to give it a boost.
During the winter, give your lawn a dose of iron sulphate in December / February for a boost of colour and to harden the turf against the cold, snow and ice.
Looking for more information on why you should feed your lawn? See our guide on “what is lawn fertiliser“.
Final Verdict
The approach you take towards lawn feeding is down to your personal preference. Both granular and liquid lawn feeds have their place.
We recommend you use granular fertilisers as a base feed and liquid lawn feed as a top up when your lawn needs it.
If you decide to only choose one feed for your lawn, choose granular.
