This article will look at the various options in terms of long term weed control. The two main methods are to lay down a weed fabric or polythene sheeting.
The first thing to look at it the type of sheets you should use. I will be looking at long term heavy duty use, you are able to get lighter versions of both types of products, but I will be concentrating on a long term solution for perennials and leafy garden pests.
OK so when it comes to buying weed fabric it can be called a number of different names; geotextile, membrane, ground cover and mulch fabric so if I mention these names do not get confused, they are all the same thing. Weed fabrics come can be manufactured in a couple of ways, they come in spun-bonded and woven (both produced from polyethylene). For long time use you will need the woven style (at least 100gsm), for light use you will only require the spun-bonded (at least 50gsm). The GSM is the grams per square metre; this number applies to both woven & spun-bonded material and is a good indicator as to the quality of the fabric, the higher the better. In this article I am focusing on the woven 100gsm in regards to mulch fabric. The polythene I am referring to in this article is the black 250mu style.
Garden ground cover and polythene are used by professionals and also amateurs; there are differences between the two. Heavy duty polythene is often thicker and is a continuous sheet without any perforations. Geotextile is a woven fabric that has a very tight weave, leaving minute holes in it; the use for these holes will be explained later. In terms of price per square metre they are fairly similar; if anything the polythene is slightly more expensive, this becomes more apparent the larger the area you need to cover.
Both products are most common in black; you can find green fabric and also other colours of polythene. When using these sheets you want to block out as much light as possible; you do not want the perennials underneath to photosynthesise. Once they are laid down then over time the weeds will die and degrade. You can lay turf, gravel and mulching products over both plastic and geotextile at any stage of the process; it will continue to work underneath.
Both plastic and geotextile are available in sheeting and roll form; this depends on the manufacturer and the preference of the shop selling it. In terms of pegging them down there are dedicated weed anchor pegs that can be purchased, although they work with both, they are really designed for use with the mulch fabric. For harder ground you should upgrade to steel pegs as they are a lot stronger than the standard plastic style.
And so to the pros and cons. In terms of both of the styles of prevention they are both effective and long lasting as long as they are laid properly; they both get a tick in the box for that (polythene being thicker can sometimes last a bit longer). They are both suitable for heavy duty applications and are easily installed.
Ground Cover is usually preferred in wet weather areas; It’s small holes left by the weaving allow water to pass through to the soil below; the benefits for this are twofold. The first benefit is that water will not pool like it will with polythene, it will pass through and enter into the soil below. The second benefit is that allowing the water to get through helps to enrich the soil below and keep it healthy. The earth has a natural drainage system and the geotextile makes full use of it.
Here are some tips for buying and using any type of weed control.
- The more heavy duty the better!
- Use pegs where available
- If using polythene without covering perhaps create a slight slope for a water run-off
- If using multiple sheets overlap by a number of inches
- Clear the area to the best of your ability before applying
- It is advisable to use spray weed killer prior to laying
- Apply in the dry
Now you have had all of the information I can make a recommendation. Due to the drainage benefits the fabric would be the first option, it is easy to cut and lay and does not give off any chemicals. The soil will stay rich and clear for use in the future.