Lawn sand is a combined weedkiller, moss killer and lawn fertiliser - though usually sold as a moss treatment. It consists of ammonium sulphate, iron sulphate and fine sand. It should be applied between April and September, in dry conditions, but preferably when rain is expected within a couple of days.
Follow the application instructions on the packet, but do not exceed the stated application rate otherwise the grass may be killed - as well as weeds and moss. Annual use will also keep worms, and therefore worm casts off the lawn.
Lawn sand can be bought at most large garden centres together with the smaller nursery type centres. It is not the most popular of lines to stock, so difficulty may be experienced in finding a lawn sand supplier in your area.
Because of the high weight to value ratio, it is not normally available online. Where lawn sand is available online, then expect to pay a premium price for either the product, or the carriage costs.
Lawn sans is a relatively old fashioned, traditional way of feeding lawns - and killing moss. It does not get to the heart of the problem with moss - simply kills what is visible in the lawn. If you have a persistent moss problem, then you will have to deal with the problem - not simply treat the results. Simply killing moss, is like trying to cure a cold with a handkerchief!
The active ingredient for killing moss with lawn sand Lawn Sand, is iron sulphate. The other main ingredient - Ammonium sulphate - is a general fertilizer with a high Nitrogen release, which will help to green up the grass. The sand in lawn sand - usually fine, is not a magic ingredient. It is simply to enable the chemicals to be spread and distributed properly. Without the sand as a 'carrier' it would be difficult to spread the chemicals thinly.
When asking for Lawn Sand, make sure that the assistant is aware of what you actually want. It is NOT, simply sand for the lawn! I have often seen sand for the lawn labelled as lawn sand. NOT THE SAME THING! The other thing to be aware of, is conversely, you DO NOT USE Lawn Sand for top dressing the lawn. For this you need to use washed sand (No Chemical content.)
If you have problems obtaining lawn sand, then you can easily make it for yourself. You simply need a supply of dry fine sand - Silver sand is ideal - or from the Builder's Merchant, you can get a bag of Block Paving Sand - Kiln Dried. Iron Sulphate and Ammonium Sulphate (Sulphate of Ammonia) is available in small packs - or larger quantities at most good garden centres. When you buy the chemicals, make sure that you obtain powdered forms and not granules. (The granules will simply fall off the leaves of the grasses or weeds, whilst powder will adhere to the damp grass and moss.
The formula is simple to mix and prepare. By volume - simply mix the three ingredients together in equal proportion. I.e. - a container full of each. Wear Gloves, or the Iron Sulphate will stain your hands - also your clothes. Do the mix outside - but not on a windy day, and avoid breathing in the dust! (Common sense really.) Only mix as much as you are going to use, for it does not keep very well. With such a simple formula of ingredients, it should be easy to mix the right quantity - even if it takes a few mixes.
Lawn sand will kill the existing moss and many different types of weeds, and at the same time help to green up your grass. The Sulphate of Ammonia is a high Nitrogen fertiliser, which is essential for good strong grass.
Lawn Sand is often recommended by organic organisations and websites - instead of using lawn weed and feed! lawn sand is NOT ORGANIC! The two chemicals used are often found in normal weed, feed and moss-killer. Just because it is old fashioned, and probably what your grand father used, does not make it organic. Much the same as many other old-fashioned recipes. (Another subject!)
You can either spread - broadcast - the mix over the lawn when the grass is damp. Early morning is good. If you do this, make sure that you walk backwards so as not to tread on the treated area! If it does not rain within a couple of days, then water it in - using a sprinkler. Do not walk over the treated area. After a few days - or a week - you will see the moss areas turning black. This will also be the case with any weeds - in particular the broader leaved varieties. Some of the grasses may also turn black - especially if you have over-applied - but this is normally temporary, and rights itself within a week or so.
The other alternative is to use a mechanical spreader.
Mixed in the proportions as above, then it should be evenly spread at a rate of around 4ounces per square yard. Mark out your lawn in 1 or 2 yard squares using string lines. For estimating larger areas, this works out at around 3kgs per 22 sq. metres or - as it is old fashioned, but still good - 6.5lbs per 26 sq. yards.
You may have to re-apply after 4-6 weeks to fully kill off the moss. Do NOT over apply, just to be on the safe side. If you do, you may kill off some of your grass!
By David Hughes - firstname.lastname@example.org