Fertiliser can be confusing. Especially when it comes to NPK – whaaat?
Actually, when it’s broken down, it’s not that bad really. Fertiliser has one main function when it comes to gardening. To help things grow.
I’m not going into the detailed construction of it in this post but it generally contains 3 core nutrients. Nitrogen (N), Phosphate (P) and Potassium (K). That’s known as the NPK Analysis. And you need different amounts of each nutrient at different times of the year.
Keep reading to find out more about that.
So what’s in this post?
- Why fertilise the lawn
- When’s the best time to fertilise the lawn
Why fertilise the lawn
Fertiliser is particularly useful when it comes to lawns. It helps the roots, the colour and the growth. While you might think it’s feeding the lawn, it’s actually feeding the soil.
Because having quality, nutritious soil is the NUMBER 1 aspect to creating a great looking lawn. And keeping it great all year round.
Using fertiliser to increase nutritional levels in the soil, that are specifically created for lawns, will mean it can out-compete weeds, prevent moss (to a certain extent) and keep its thickness.
What’s more, if you have high quality soil, your grass will much more easily out compete weeds and disease.
When’s the best time to fertilise the lawn
As a general rule you should fertilise the lawn, using a granular lawn feed every 10-12 weeks throughout the year – thats 4 times – one for every season. This is the same regardless of whether you’re using an organic or non-organic fertiliser.
But depending on the season will depend on which is the best fertiliser to use at that time.
You need more nitrogen during the growing season (Spring & Summer) and much less nitrogen during the cooler, wetter seasons when the grass is more dormant (Autumn & Winter).
Then, slap bang in the middle each granular feed during Spring & Summer only, you can apply a liquid fertiliser. This acts as a supplement to the granular applications and is not as important as those but can still help your lawn get through the stresses of hot weather.
What to use when fertilising the lawn
The most important by far are the granular fertilisers. These are the ones that boost growth or protect the roots to make it though harsh weather conditions.
Slow release (nitrogen) fertiliser
Slow release fertilisers are seen as the cream of the crop in the soil feeding world. Mainly because they can keep feeding the soil for up to 3 months. They are slightly more expensive but it’s definitely worth the extra spend.
They are produced by coating the urea in water-insoluble sulfur or polymers, which releases the nitrogen slowly. The coating breaks down slowly over the course of the feeding. each time it breaks down a bit more nitrogen is released.
Some organic fertilisers like Hoof & Horn also can release nitrogen slowly. However, it’s less clear about how much of the nitrogen is slow release in comparison to manufactured slow release nitrogen fertiliser
Quick or Standard release (nitrogen) fertiliser
Quick release nitrogen is basically one that doesn’t have a slow release coating. Actually meaning it’s a standard release really.
Nitrogen without a slow release coating will dissolve into the soil much quicker into the soil. The biggest problem with this is that once the nitrogen has dissolved, the soil will essentially be ‘starved’ of notrigen and you’ll need to do another feed after about 6 weeks.
The main benefit of quick release nitrogen is that your grass will be given a surge of growth. So, if you’re looking to host a party and need to give your lawn a quick boost, then this could be the product for you.
Bear in mind, that quick release has a much higher chance of burning the grass, so you should avoid applying it during the hot summer months.
All-in-all I recommend using a mix of quick and slow release in the Spring, then a 100% slow release in the Summer
Liquid fertiliser vs granular fertiliser
While the granular ones are most important when it comes to all year round lawn care, liquid fertilisers are the perfect supplement for the hot summer months. You can choose between a nitrogen based liquid or a liquid seaweed.
How long to wait between each application of fertiliser
Typically, you should wait approximately 10-12 weeks between applications of fertiliser on your lawn.
However, it’s not always as simple as that.
Mainly because it depends on
Are 1-2mm granules or 2-3mm granules best
Both 1-2mm and 2-3 mm are pretty much the same, or at least do the same. The main difference is that smaller granules will give off more dust than larger granules. However, the smaller granules are likely to work their way through to the soil quicker if you have a large build up of under growth.
I personally prefer 2-3 mm granules best because it’s easier to see where you’ve applied and you can sprinkle in any missed sections after doing your application.
If any product contains Iron (Fe), which suppresses moss then all of that product needs to be produced as 1-2mm granules. That’s because iron is so fine. So, our Specialist Winter feed is a 1-2mm, whereas our Spring feeds are generally 2-3mm granules.
Is it fertiliSe or fertiliZe
This is one for the pub quiz (hope not) – My understanding is that in America it’s spelt with a ‘Z’ and in UK it’s spelt with a ‘S’