When you decide to grow your vegetables (or other plants) organically, you will immediately be faced with one major problem, how to control weeds without using weedkillers. I have experienced this problem on my sizeable allotment over the last two years but have now found the perfect solution. In year one I spent days on my hands and knees using hand-tools to weed out every last weed whether they were annual or perennial weeds. The consequences of this were long term, as I now have very painful knee joints and it is very uncomfortable to kneel down or stand up again, (so much so that my Doctor even had my knees x-rayed to see if there was a problem there, only they found nothing in the bones at least). This year I was determined I wanted to avoid this chore as much as possible, as well as improving our already very heavy clay soil. I wanted more time to do other things once the actual planting was done, and so I looked into what substances I could easily obtain free of charge to mulch my entire allotment once the plants were visible, and therefore avoid the massive amounts of hand weeding I had ensured the previous year.
The investigations I made into sourceable materials produced fruit almost immediately. I arranged for my large vegetable allotment to be ploughed, cultivated and rotavated as normal and then planted my numerous seeds in position. The next stage was to wait until the seedlings and plants were clearly visible so that I didn’t accidentally mulch over them and prevent them growing. Yes this did involve some weeding, and I needed to mainly hand weed out the perennial deep rooted weeds such as dock leaves, creeping buttercup and an as yet unidentified weed that appears to grow from small chunks of woody root that send up crocus-like shoots (if even a tiny portion of this weed is left in the ground it sends up further shoots). The annual weeds I simply skimmed off the tops of using a dutch hoe, safe in the knowledge they would immediately die, and so long as I mulched the area thickly, further growth of new annual weed seedlings would be prevented.
My next consideration was what would be the best all round mulch to use. My first instinct was to obtain as much cow manure as possible, because living on an island (Guernsey), famous for its dairy cows and their milk, I assumed cow manure would be easy to obtain free of charge, however, I was wrong, as I discovered the farmers water this down and spray the liquid onto the fields as a “slurry” or “liquid manure”. I have to say I have used cow manure as a mulch in the UK and it produced fantastic crops, but as I couldn’t get hold of any here in Guernsey I decided to explore other options instead. The options that became immediately available to me free of charge were as follows:
1) Horse manure. This was free as most people want to get rid of it. The disadvantage I rapidly discovered was that it tends to be full of weed seeds because horses only have one stomach, (unlike cows who have one stomach divided into four to ensure the seeds are digested twice, once when the cow initially swallows the grass, and a second time when they regurgitate it to chew it a second time, chewing the cud, before it then travels through the remaining sections of the stomach and is passed as manure). This means a certain amount of weeds will grow from the horse manure itself. The second problem is that unless it is very well rotted horse manure will burn the vegetable plant’s roots, and can kill the plants completely, so it really should be rotted for at least six months before use which means planning well ahead of planting. It is useful “raw” for using to prevent weed growth on the paths around your allotment though, and by the time you plough your allotment again at the end of the year it will be well rotted and will benefit the following years plants.
2) Grass mowings. Again these are easy to obtain whether from your own garden or from people who have large areas of field that they arrange for tractors to “top” periodically in order to avoid the grass getting out of control. although these can be used straight away there is some benefit to be obtained from stacking the mowings in a heap in order to allow a build up of heat in the middle of the heap that will kill any weed seeds. Remember to turn the heap occasionally to stop the heat getting to a stage it self ignites.
3) Wood chips. These are costly to buy, but if you know anyone who has an area of land they are tidying up they will often hire a wood chipper to break down the branches and twiggy growth they need to get rid of. As dumping these on a commercial tip has become very expensive they may well be glad of someone to take them off their hands, and these too can be used immediately adding nutrients to your soil, improving the texture and suppressing the weeds effectively. One slight catch is they can act as a home for slugs, but a few well distributed organically approved slug pellets should counteract this problem.
4) Seaweed. We are incredibly lucky where we live in as much as we are only ever a few minutes from a beach and our local authorities actively encourage farmers and gardeners to help themselves to the copious amounts of seaweed that is washed up on the beaches every day. This seaweed is a problem on the island as it can be very smelly and it is not good for the tourists visiting the island. It is perfectly legal here to drive down on to the beach and remove as much seaweed as you can use. This is a perfect mulch as it is not only full of nutrients but due to the minimal amount of salt (in spite of what you might think), that remains on the seaweed it also deters slugs. The weeds do not grow through it and most odour vanishes within about forty eight hours once the sun dries out the surface layer, (so forming an odour suppressing crust). Every time it rains your plants get a natural liquid feed, and the salt content is not high enough to kill your plants so there is no need to wash it before use.
5) Spent compost.This is a great way to use up your old compost from last year. Spent compost will improve your soil texture and suppress weeds, as well as looking very attractive. If you don’t have your own spent compost contact your local mushroom farm as they will have tonnes of the stuff, (you might even have a few delicious freebie mushrooms pop up on your allotment as a bonus). Another option is to talk to your local tomato grower as they often have sack loads of the spent compost left over from the last season’s crops. You will get some weed seeds germinating on the surface of course, but these will pull out ever so easily because the compost is very soft and the roots won’t get a hold very easily.
6) Cardboard boxes. Torn up these will suppress weeds very efficiently as well as keeping moisture in the soil. They will only add a minimal amount of goodness to the ground compared to other mulches, but they will save many hours of labour and will break down into your soil bit by bit. Your local supermarket often throw these away and you will be doing them a favour and recycling if you take them home for use in your garden.
7) Straw. If you can get hold of this in the form of used animal bedding or “spoiled straw” that has got wet, then use it, as it is an excellent mulch and keeps dirt from splashing up on to your crops when they are watered, plus it stops vegetables in contact with the ground such as pumpkins, courgettes (zucchini) and outdoor cucumbers from rotting when in contact with the soil.
Tips for Using Mulch.
1) If using manures always try to make sure they have been rotted for a minimum of six months before using to avoid burning your plants.
2) Remove all perennial weeds before mulching.
3) Mulch at least four inches deep to suppress weed growth.
4) Allow for the fact seaweed is 90% water, therefore use far more than you think you will need to allow for shrinkage as it dries out.
5) Mulch carefully around vegetable plants to make sure you don’t smother the smaller ones, (you may find this a more pleasant task if you use rubber gloves assuming your chosen mulch is manure or seaweed).