‘The grass may be greener on the other side of the fence, but you still have to mow it’. – Anonymous
Why am I writing an article about lawn care, given my well known antipathy to lawns? I have a lawn myself, but I fight shy of wasting too much time and effort on what is, after all’s said and done, just grass for goodness sake.
So I’m starting a grass roots movement (pardon the pun!), to persuade you to apply a little common sense and a little science, to maintain your lawn in a reasonable state with the bare minimum of expense and effort.
What you need to do:
You want to make things favourable for the grass and unfavourable for the weeds. So the grass will choke out the weeds. Naturally.
Because plants, grass and weeds, compete, there is a fight for light and the sun (I told you it’s a war out there!). If the grass doesn’t shade the weed, the weed will shade the grass. Sun and light is food. Food is strength and life. Shade is weakness, disease and death.
Grass will shade the weeds only if it is tall enough. The shade of tall, dense turf will prevent essential light from reaching most weeds and will aid in the destruction of new weed seedlings.
Set your mower as high as it will go (3 to 4 inches).
I can almost hear you say “If I mow the grass short, it will be longer until I have to mow again.” Wrong!
Here’s the science (or common sense).
Your lawn needs grass blades to do the photosynthesis bit (convert sunshine into sugar) to feed the roots. When you cut too low, the grass has to race to make more blades to make sugar. It then grows amazingly fast. This fast growth uses up a lot of the grass’s stored sugar, and weakens the plant. It is now vulnerable to disease and pests!
The sensitive growing point for grass is near the soil.
The sensitive growing point for most weeds is near the top of the plant.
If you have a serious weed infestation, consider mowing twice as frequently as you normally do. So when you mow, it’s as if you are giving your grass a little haircut and cutting the heads off the weeds.
But still mow high.
Tall grass is healthier and can use the extra sugar to make rhizomes (more grass plants) thus thickening the turf.
Have you ever noticed that very short grass in the summer is always riddled with dead brown patches?
As with all plants, grass needs organic matter and nutrients in the soil. The best way to satisfy this requirement is to leave the grass cuttings on the lawn. Use a lawn mower that chops the grass finely. If you don’t like leaving the clippings on the lawn, then you must feed. Fertilise with an organic fertiliser in the autumn and spring. Fertilizing in the summer feeds the weeds, not the grass.
Grass is a glutton for nitrogen.
Clover can get nitrogen from the air (the air we breath is 80% nitrogen) so, when you see legumes (clover) taking over your lawn, you know that your soil is nitrogen poor.
Soil quality is very important. If your soil is like cement, add an inch of compost in the early autumn every year.
This will get microbial life and organic matter into it. There’s a big difference between dirt and soil.
This will force your grass roots to go deep into the soil. Deeper than most weed roots.
As the top few inches of soil becomes bone dry, the weeds and weed seedlings up there die while the grass still enjoys water from a little deeper.
Train your grass to make deep roots.
Shallow, frequent watering encourages “thatch” (the grass propogates with above-soil runners (like strawberry runners) rather than rhizomes under the soil – the runners weave a mat that chokes out water and air).
Since the roots are in the top inch or two of soil, a hot day will quickly dry the soil and much of the grass will brown.
Weeds and weed seedlings love a daily watering. It’s just what they need for a good start.
Water only when your grass shows signs of drought stress and then water deeply.
Watering frequently does not help in the war on weeds.
In drought conditions stick a shovel into the soil for about six inches and push the handle forward. If you can see any moisture, wait. If it’s all dry, water deeply. Conditions which require this kind of ‘intensive care’ watering are rare in the UK.
Another thing about watering:
If you are going to water an inch, it is better to water half an inch, wait 90 minutes and then water another half an inch. Sometimes when the soil gets really dry, it will repel water. This is called “superdeflocculation” (I think Mary Poppins would be impressed with this word!). If you put a little water in first, wait, and then put in more, the soil is better prepared to take in more water.
Before you make a new lawn from scratch by sowing seed or laying turf, in the light of what I have just said, consider how much topsoil you have.
If you have less than four inches of soil, you must add topsoil to give the grass roots the depth to penetrate to water.
To do a simple test, take a shovel and push it into the soil about six inches. If you can’t get your shovel to go into the soil this deep, you need more soil.
If you are getting topsoil delivered to your house, be prepared for it to bear more resemblance to ‘dirt’. You may want to have compost also delivered to your house so that you can mix the two. One part compost to two parts ‘dirt’ is a good mix.
With the above methods you will mow less, water less or not at all, and have a reasonable looking lawn.
Of course you could turn this into an obsession, as some people do.
Have pH tests. Grass loves a pH of around 6.5. If your pH is 7.5 or higher, your grass will probably never defeat the dandelions. Lower the pH to 6.5 and your grass has the advantage! But for yours truly this would be taking it all a bit too far for a suburban garden.
My own view is that too much effort can be devoted to grass. Especially something as frivolous as a lawn. I would rather have weeds.