15 Questions About the Lawn (Part 3)
10. How can we stop a lawn from yellowing ?
Yellowing is often due to the result of bad maintenance (lack of water or fertilizer, cutting too short, walking too much on it, etc..). The stolon, a vital part of the lawn grass, is damaged or suffering. The application of a fast-acting fertilizer after the spring mowing helps the lawn become green again. A second dose of fertilizer in autumn (a slow-acting one this time) allows the grass to restock its reserves and to grow stronger the following spring.
A badly sharpened lawnmwer blade cuts the leaf grass irregularly, which yellows at the tip. If you don’t gather the clippings after mowing when the lawn is dense, this will suffocate the lawn which yellows, and will also provoke diseases.
In hot and dry periods, you should water the lawn two or three times a week, preferably in the evening, using 5 to 10 litres of water per square metre ( leave the sprinkler on for 15 to 20 minutes). Don’t cut too short and don’t fertilize a dry lawn.
Animal urine, especially that of female dogs and foxes, burns the grass badly and can be responsible for ugly yellow patches. If you catch a dog urinating, pour a large quantity of water on the area immediately to dilute the nasty effects of the urine. It is best to forbid dogs access to the lawn, as they have a tendance to urinate in the same place, which will damage the lawn for good. To repair the damage, remove 5cms. deep of lawn, fill in the hole with good soil and place a slab of ready-made lawn in its place.
11. How can we get rid of moss which invades the lawn ?
The presence of mosses on the lawn is a sign that the soil is badly ventilated, that the lawn is often in the shade and that there is too much humidity. Mosses develop especially in acidic soils, so lime the soil every two years at springtime.
Scarification of the soil in September is a very efficient way of removing moss. Add sand to the soil after scarifying to lighten the soil. Small areas can be ventilated by walking on the soil with spiked shoes, by rolling the lawn with a spiked roller or by using a garden fork.
Chemical treatment of mosses should be carried out in February and March. The most popular product used is iron sulphate. It turns the moss red, but also reddens flagstones, rocks and metal objects, so be careful when applying it. Although it is inexpensive, it is replaced more and more by Dichlorophen, which can be applied to all surfaces without staining. Anti-moss fertilizers (containing iron sulphate) and weedkilling anti-moss fertilizers also exist.
12. How can we rejuvenate the lawn ?
If the lawn starts to yellow and contains moss, start by scarifying.
Passing the subsoiler, whose blades dig shallow troughs, allows us to dig up the stubble and the felting, that is, the dead parts (and therefore yellow) at the base of the grass tufts. Scarification also helps water to penetrate the soil better and therefore helps the fertilizer to infiltrate better, feeding the roots of the tufts of grass.
Scarification also eliminates mosses. It should be done twice a year, in spring and at the end of the summer or at the beginning of autumn. The subsoiler should be passed the length of the lawn once and then once the width of the lawn. The material recovered should be carefully removed (you can add this to your compost heap). Many different models of subsoilers exist. Scarification should be completed by an adding compost or organic fertilizer to the lawn.
13. What can we do when the lawn is all bumpy ?
Try passing the roller in wet weather and systematically after mowing. The roller should have rounded edges to avoid it leaving traces on the lawn. The weight of the roller should be varied according to the ground (fill it with water or sand) and the work to be done.
A full renovation should be carried out if the ground is very bumpy.
Start by getting rid of the old lawn, by spraying a systemic herbicide (containing Glyphosate for example). This product leaves no residue in the soil, so you can sow 3 to 5 weeks after applying it (the time it takes to work). Rake away all the grass burnt by this product. Start levelling the ground, flattening the bumps. Keep the recovered soil to fill in holes later. To homogenize the surface, add compost if needed. Lighten the ground by working it over with a subsoiler. Sow the grass seeds and cover them with a light compost. Roll the ground to obtain a smooth surface. Water abundantly.
14. When are the best times to revovate the lawn ?
It is advised to renovate at two distinct periods :
In March/April to eliminate mosses and weeds by using selective herbicides.
Between the start of September and mid-October to carry out new sowing.
15. What actions should be carried out on the lawn after the summer ?
SEPTEMBER
Mow and water once a week. Apply an anti-moss compost for lawns. This is a good time to sow a new lawn. Roll after every mowing. Ventilate very compact lawns. Scarify again. Cut the edges of the lawn.
OCTOBER
Mow for the last time around the 10th or the 15th of the month. After scarifying, apply compost on lawns which have yellowed. Remove dead leaves. Treat against moss.
NOVEMBER
Remove dead leaves. Finish scarifying. Turn the old lawns over by incorporating the grass into the soil and by adding a compost.
DECEMBER
Prepare the patches of soil which are going to be renovated or transformed into lawn in the spring.