Fertilising your lawn is a pretty straightforward job, right? Buy fertiliser, dilute it if it’s liquid, spread it out, and water it in if it’s granular. Actually, there’s a little more to it… as you’ll know if you’ve ever applied fertiliser only to find that a few days later, your lawn looks worse!
Where did it all go wrong? Here are some of the usual mistakes…
1. Too soon
‘This fertiliser does nothing!’ could be the mantra of the overkeen gardener! But it’s probably not the fertiliser that’s the problem – it’s the timing of application.
If you apply fertiliser too early – that is, before soil is consistently above 14°C – you’re essentially pouring good lawn food (and good money!) down the drain. Grass must be out of its winter dormancy and actively growing before it will benefit from a dose of fertiliser.
Applying fertiliser at the right time of year will ensure you get the most out of your lawn. Click here for seasonal fertilising information to make sure you apply your fertiliser at the right time, every time.
2. Too much
Over-fertilising your lawn will cause sudden growth of leaf and thatch. However, this rapid leaf growth is not matched by equivalent root growth, which means you’ll be left with a root system that is unable to supply the lawn with all its water and nutrient needs. And this is not the only problem.
As fertiliser is primarily made up of mineral salts, excessive fertilising will also cause a buildup of salts in the soil, which encourages water to be retained in the soil rather than being absorbed by the roots. This dries out your grass, causing discolouration or, in severe cases, even death of the lawn.
Finally, although nitrogen is an essential nutrient for lawns, excessive nitrogen can kill the microbes that support healthy grass, resulting in burnt grass.
Signs you may have over fertilised your lawn include:
Browning leaf tips and yellowing lower leaves (‘fertiliser burn’)
Darkened, weakened roots
A salt-like crust of fertiliser on the soil surface.
3. Too erratic
The method of application is just as important as the fertiliser itself. Chuck fertiliser about willy-nilly and you’ll end up with a lawn that looks like it’s been maintained by a goat! Instead, apply fertiliser as you walk systematically back and forth across the lawn to ensure a uniform spread. For granular fertiliser, it is best to use a spreader. For liquid fertiliser, use a watering can.
4. Too strong
Fertiliser concentrate that has not been properly diluted can kill the microbes that keep grass healthy and result in grass burn. Liquid fertiliser can simply be diluted appropriately before application, but granular fertiliser is a different story.
Granular fertiliser must be watered in after application to solubilise it. This is why those in the know will often fertilise just before rain is forecast. But be careful not to apply it if you’re expecting a deluge of rain, as too much rain will wash the fertiliser away. Apart from the fact that your lawn won’t get the full benefit of the fertiliser, this can be harmful to the environment.
While many fertilisers are similar, not all fertilisers are the same. For best results, make sure you always follow the label instructions for the specific fertiliser that you are using.