What to feed your lawn this month
Apart from a few sunny days, this spring hasn’t really been all that different to winter. Which is unusual, even for Scotland. Cold, wet, miserable. But surprisingly, the soil seems to have warmed up enough for our lawns to start growing.
Grass plants grow when the soil temperature reaches 6 degrees centigrade. And when they start growing, they start using up the nutrients in the soil.
How do plants find their food?
We humans need a balanced diet if we are to grow strong and healthy. Plants are no different. They just obtain and process their food in a different way to we do.
Where people go shopping, foraging and gardening to find food, plants can only harvest sunlight and carbon dioxide through their leaves and absorb water and minerals through their leaves.
People food is made up of complex chemical compounds that our digestive systems break down into simpler compounds before rebuilding them into what the body needs.
Plants absorb simple compounds and then build them into more complex ones.
So, a plant needs to have the right compounds in the soil before it can thrive.
What happens if the correct nutrients aren’t available?
If a person doesn’t have a balanced diet – for example if they eat lots of carbohydrates and fats but no protein – the effects might not be immediately obvious. My grandson for example could probably eat burgers and fries all day every day for the next 10 years and never put on weight. However, when he’s older, he’d very likely become very ill. Which is why, if you’re reading this Justin, Nanna doesn’t let you eat junk food.
When a person doesn’t get the right vitamins and minerals, he or she develops awful illnesses – rickets, scurvy, anaemia and the like.
Your lawn is no different. If it doesn’t get the right balance of nutrients it may look OK but ultimately it will suffer. Lack of nitrogen leads to pale, spindly leaves that cannot harvest sunlight efficiently. Lack of phosphorus or potassium weakens the plants’ immunity to diseases like fusarium patch or redthread disease.
When lawn plants are weak, they cannot repair the damage done to them by the occasional leatherjacket or chafer grub and they find it harder to cope with heavy traffic.
So, while you may be able to get away with not feeding your lawn in the short term. In the long term you will probably come to regret it.
There are so many lawn feeds in the garden centre. Which one is right for my lawn?
If you are looking after a bowling green or a sports stadia you will need specialised fertilisers. But for a garden lawn, there are two basic formulations you need to know about.
Autumn/Winter fertiliser – promotes strong roots and disease resistance while the plants are not growing much.
Spring/Summer fertiliser – contains Nitrogen to support the fast growth we see at this time of year.
Both formulations also contain essential micro-nutrients (the plant equivalent of vitamins and minerals) to support general health.
If you’re choosing products in the garden centre, look at the NPK content of the fertiliser. It’s usually shown as a set of three numbers, like this 14:4:8
That indicates that the feed contains 14% nitrogen, 4% phosphorus and 8% potassium. Perfect for summer. (The other 74% is the carrier that makes it safe and easy to handle the fertiliser with a small amount of minerals)
In winter, you need low (or no) nitrogen. In summer, 14 -16% nitrogen is just right. If you have too much, it will scorch the lawn.
How often do I feed my lawn?
Between march and august, you should be applying a spring-summer fertiliser every 6-8 weeks. Apply it according to the rates recommended by the manufacturer. When it comes to fertiliser, more is not more.
Recommended lawn feed for Scotland
This one! You can order it online, it will be delivered to your door and it has all of the instructions with it. The packaging is designed so that if you don’t use all of the contents at once, you can re-seal the tub and use the rest of the lawn feed another time.
More about spring lawn care