Sustainable Lawn Care

It has been a little while since we looked at the subject of lawns and their care, so lets go over the main aspects of having a great lawn.

The best lawns are a combination of fescue and the new fine rye grasses with no brown top.

Brown top is a throw back to the days when there were only course rye grasses available. A lawn with brown top in it, will have on going thatch problems. Thatch is the debris that builds up on the surface of the soil and creates a number of problems if left to build into a thick layer. This layer captures moisture and reduces the moisture level in the soil. The feeder roots of the grasses tend to grow into the thatch for both moisture and nutrients. Problem being is that thatch dries out quickly in sun or wind leaving the feeder roots to perish and likely a browning off of the grasses.
Lawns need to be de-thatched twice a year, spring and autumn and in some cases more frequently.

This can be done by using a special rake, a scarifier machine or by spraying the lawn with Thatch Busta.

The later is the easiest and what the Thatch Busta actually does is feed the microbes that will break down the thatch. By feeding them their populations increase incredibly and an inch of thatch can be cleaned up in a month.

Weeds are a problem in lawns that do not have a thick mat of grasses. When, by over sowing a lawn several times with good quality lawn seed, you create a thick mat of grasses that make it very difficult for weeds to establish and grow. The few that do grow can easily be cut off below ground level with a sharp knife. When we think of weeding the lawn we automatically think of lawn weed killer sprays.

This is not good for two basic reasons, the recent increased prices of most lawn weed sprays are now about $30.00 a bottle which makes it an expensive job. The weed killers are dangerous to our garden plants, they cause health problems to our pets, wild life, our children, (if allowed to play on a treated lawn), the clippings are dangerous to compost and the soil life is also affected by these poisons.

Result is you pay a lot of money and create a number of problems. (hopefully you do kill the weeds).

Recently I had an interesting conversation with a fellow gardener whom told me how she controlled and made good, a very weedy lawn without the use of the chemical sprays.

What she did was to use nitrogen in the form of sulphate of ammonia over the lawn.

This was applied when the lawn was dry and the product was broadcast by hand in the same way as one would sow lawn seed by hand. North/South and then East/West. A lawn spreader could be used instead if preferred. Now the nitrogen when it gets a little moisture from dew activates and burns. It burns off both weeds and grasses so for a time you will have a brown lawn. The grasses come back and most of the weeds don’t. Interestingly it can also kill off inferior grasses, leaving the better grasses to colonise the lawn. A month after application she would give the lawn a good dose of garden lime to overcome any damage done by the sulphate of ammonia.

Sulphate of ammonia is fairly cheap to buy especially in the bulk 25Kg bags and one bag will do a lot of lawn. My gardening friend told me that within several weeks her grasses had recovered to make for the best lawn ever. Sulphate of ammonia can also be used to spot treat those odd weeds that appear in lawns by pouring a little into the centre of the weed or in the spot where it is growing.
If you are to use this relatively safe method of weeding your lawn then after every thing has browned off spray the lawn with Thatch Busta as well as spreading the lime. This would speed up recovery.
It would likely be a good idea to also oversow the lawn with some fresh lawn seed. (No brown top in the mix).

Moss growing in the lawn is another problem but this can easily be solved by spraying the lawn with Moss and Liverwort Control. It kills the moss and often prevents the re-appearance of it for sometime.

Sulphate of Iron is sometimes recommended, but the iron only burns off the top of the moss which often re-appears again soon after, dependant on conditions.

For feeding the lawn I would recommend Bio Boost. It is a natural slow release food and can cost only about $1.00 a kilo in the 25 Kg bags. (at this stage only available from PGG-Wrightson or Fruit Fed outlets.) The same can be used to great advantage on all gardens.

Now we come to the lawn pests of which there are three, grass grubs, porina and root nematodes.

At this time of the year most of the grass grubs will be pupating deep in the soil to emerge as beetles in the next month or so. Controlling the grubs in the soil can be difficult whether you are using a chemical or natural method so it is easier to control the adults by means of water and lights when they are on the wing. (I have the full explanation of this method in my book Wally’s Down to Earth Gardening Guide).

If you wish to treat the lawn for grass grubs it pays to lift turf and check for the number of grubs near the surface and if there is not a good number in a square foot then don’t waste your time and money.

Normally the best treatment time is about April to June.
Porina caterpillars are a native moth that live in the soil in burrows, and in the early evening emerge and eat at the base of the grasses often causing bare patches. They can be detected by the hole that is the entrance to their burrow or by the bird activity trying to rip open the soil for a nice feast.

Easy to control by a spray of Neem tree Oil applied late in the day to the lawn, which has recently been mowed.

Root nematodes is not something that is easy to detect as they are small pests that attach themselves to the roots of the grasses and suck. They do not kill the grasses normally but will take away the luster of the growth. To determine if you have the problem mark off about 5 to 10 square metres of your best lawn and sprinkle Neem tree Granules over the area. If after a month or so you notice that the grasses in the treated area look lusher and better than the rest then you do have the problem.

Treat then, the rest of the lawn. At the same time you are likely to clean up any grass grubs near the surface and porina in the treated area.

There are a number of things you can apply to your lawns to make them healthier and better looking.

Firstly never cut more than one third off the height of the grasses in one mowing and never mow lower than about 25 to 30 mm. (Talking about millimeters  and centimeters a recent article about straw potatoes should have read mm not cm).

Applications of lime, gypsum and dolomite every so often is great value for your lawns.

Occasional sprays of Magic Botanic Liquid and Perkfection will also build up the health of the grasses.

Ocean Solids can be also mixed and dissolved in water and sprayed over the lawns for the advantage of the minerals it contains.
Grasses are another plant, just like your flowers and vegetables and when they are cared for they will reward you with their natural beauty.

4 comments on “Sustainable Lawn Care

  1. Andy Fairbairn on said:

    Our lawn was sown in April and struck really well with too much plant population in places. In these areas black patches have appeared which look like fungus and it has killed the grass. Do you have any idea what this could be and do know what we can do to fix this.

  2. john pryor on said:

    can you please name one or two suppliers of sulphate of ammonia in crystal form in 25kg bags (or thereafbouts) in the Christchurch region

  3. W Clouston on said:

    So we have discovered grass grub on our two year old ready lawn!
    The birds have damaged quite a portion of it- we have now treated for the grub, using diazinon.
    Do we resow/oversow the affected area or will the grass regenerate in the spring?
    We are in the Christchurch area.


  4. Hi Bill, Make a grass seed and soil mix – basically mix some seed with some dry soil and dress the areas. It will take quite some time to germinate in the cold weather – perhaps wait until early spring. You may need to weed the areas but you should be fine.



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