If I closed my eyes the black tangled roots of horsetail danced before them. When I first sunk my fork into the soil, I didn’t know what the slightly menacing thin ropes of doom were. But I soon came to realise that any subterranean investigation yielded miles and miles of the stuff. It’s one of those weeds, like bindweed and dandelion and nettle that I know I’ll never eradicate, but it can be controlled so that it’s not too much of a problem. These days I recognise the roots of weeds as just well as I recognise their tops. After a few hours of digging I always see their visual representations behind my closed eyes – the livid yellow of nettle, the leek-root white fronds of creeping buttercup (my most loathed adversary), the long rubbery yet brittle lengths of bind weed. Mr. J says I’m a weed obsessive, and he’s probably right, so expect a few posts, as well as this introductory one, on what they are and what to do about them. I hope it’s useful.
Weeds are plants that grow where you don’t want them to grow. Common weeds are our most successful plants and they are perfectly adapted to growing quickly on any bare earth. There are two important distinctions that you need to know between types of weeds. Weeds are either annual (they grow for one season only and are spread by seed); or they are perennial – which means that they grow back every year and have a variety of methods of spreading – through roots, spores or seeds.
Should I get rid of weeds?
For the most part weeds are bad news for growing fruit and vegetables because they compete for water, light and nutrients. Some weeds will crowd out your crops completely if left unchecked. So it is a good idea to keep them under control. This will take up a large proportion of your time on the allotment. But knowing your enemy can make things a bit easier.
Hoeing and digging
Annual weeds can be hoed in dry weather – in damp weather the hoe will simply move the weeds around, and they will re-root. Whereas in dry weather it is possible to sever the leaves from the roots and they will whither and die off. If you can help it, don’t allow these weeds to go to seed (that is to flower) because they can produce thousands of tiny seeds that stay viable in the soil for years (think dandelion clocks). It is very difficult to eradicate perennial weeds since they are experts growers and evade all attempts at eradication. However, it is possible to weaken them significantly. Initially it is worth digging out any perennial weed roots – ask your plot neighbours for guidance on what to look for – and following one of the techniques below for disposing of them safely. In the future simply hoe or clip the tops off and the weeds will be weakened because they won’t be able to store as much energy in the roots because the leaves won’t have been able to soak up the sunshine. Weed tops can be added directly to your compost heap, and will contain a great many beneficial nutrients that the weeds have gathered from the soil.
Pros: No nasty chemicals in the soil or the air
Alternatively, if you are not going organic, it is possible to use chemical controls. Follow the instructions on the bottle carefully in order to use the product responsibly and as safely as possible. However, a word of warning. One of the most prolific weeds on our site (as on many sites) is horsetail. Chemical control will have very little effect on this weed since its leaves are covered in a coating of silica, which stops liquids from penetrating.
Pros: Quick (ish) and easy
Cons: Many people grow their own food so as to know that they are not ingesting a cocktail of chemicals; eradicating all perennial weeds apart from horsetail means that the horsetail has less competition and will be more likely to proliferate.
Improving or worsening your weed problems
Rotavating soil which has perennial weeds in it will simply chop up and spread the roots of the plants allowing them to re-sprout and to spread. It is better to dig weeds out or to practice a no dig approach (see list of books for handy info). Growing certain vegetables will help to clear the ground of weeds because they will either shade out the weeds with their dense foliage, will crowd the weeds out, or will loosen the soil making it easier to remove perennial weed roots. The best vegetables for this purpose are potatoes, squashes and courgettes. The least effective are onions and carrots.
What do I do with the waste once I have weeded?
A common concern for new plotholders is what to do with the perennial weed roots that have been unearthed through digging. The good news is that the weeds will provide excellent nutrients to your compost heap since they are often deep rooting, mining the soil of goodies that are stored in their roots. Many of these weeds – dock, dandelion, horsetail, bindweed, ground elder, nettle, creeping buttercup etc. will regrow from tiny pieces left in, or returned to, the soil. However there are a number of safe ways of disposing of the weeds on your plot.
Stewing Place all the weeds in sealed black bags until they have turned to mush, and then add them to your compost heap or bin.
Pros: Easy to do
Cons: Can take up lots of space with unsightly bags
Submerge the weeds in water for 6 weeks, and cover the container with a lid. Use the waste-water as a fertilizer. Return the drowned weeds to your compost heap or bin to rot down fully. Pros: Having a good source of readily available organic fertilizer Cons: Stinky, stinky, stinky.
Hang weeds over a rack or a wire, or lay them out in a single layer on plastic sheeting to desiccate in the sun, then add to your compost heap once they are fully dried out and crumble easily between your fingers. Pros: No smell Cons: You may have too many weeds, it is quite a messy way to do it.
Hot composting Hot composting is a technique wherein carbon rich brown materials (woody waste, paper, cardboard etc.) is mixed in the correct proportions and large volume with green materials rich in nitrogen (soft leafy growth, urine, animal waste etc.) and the chemical and bacterial reactions between the two cause the heap to heat to 40-70 degrees centigrade killing all weed seeds, perennial roots, pathogens, and diseases.
Pros: Works much more quickly than a traditional cold compost heap, safely composts more diverse waste; unlikely that small critters like mice will want to set up home in your heap because it will be too hot.
Cons: Is fiddly and requires quite a bit of know-how and attention. N.B. It is possible to purchase hot composting bins, which makes the process easier, but they are very expensive indeed. I will review my own hot composter soon. The nature of allotments is that they will have a lot of weeds. And there are various ways of tackling them. Whichever you choose, if you are an allotment holder you are likely to become something of an expert on weeds over time, and you will definitely have more conversations about weed eradication than you ever thought likely.