Weeding methods

We all do it and indeed much of our total gardening time and effort is devoted to it yet it remains one of the least attended to areas of horticulture. Few books, or courses, ever devote much space to weed control but good weed control is essential for all branches of gardening and especially in the kitchen garden where weed competition is fatal to many crops.

Because so much of our effort is devoted to weed control we have it in our interest to do it efficiently yet surprisingly many of us unwittingly make weed control harder work than it needs be. Of course it goes without saying that the only sensible way to control weeds is to get rid of them all to start with, but that is another article in itself. In a maintenance situation the best weed control is having other plants filling the space preventing the weeds getting in, and failing that then mulching. But for many of our garden crops, onions for example, the competition of other plants close nearby is as detrimental as weeds, and such as onions do not respond well to most sorts of mulching.

So most of the time we either hand weed or hoe as we try to maintain bare soil between our plants. These can be very effective methods but often our techniques can be improved. First it helps to know your weeds particularly those that are perennial as these are more troublesome than annual weeds. The latter can be excessive in their numbers but do not have the persistence of the long lived weeds. The perennial weeds need to be attacked at least once weekly from the start of the growing season to be totally exterminated. Annual weeds only need attacking every other week or so to keep them under as few can germinate and set seed in less than six weeks or thereabouts.

Indeed the secret of success is persistence, if you regularly hack the weeds to bits they die, whilst the longer you leave them growing the stronger they get. The old adage has it that if you hoe before you see a weed you'll never see one. This is true as hoeing disturbs the weed seedlings and chops them up before they have even emerged. Mind you, you do not have to dig up the roots only deprive them of leaves; Ground elder can be eradicated by simply picking off every leaf twice a week from early spring; the roots eventually just shrivel away.

Any other way of removing the leaves is as good if it is done frequently. A lawnmower or nylon line trimmer or just a set of shears will do. It does not matter; the important thing is to keep removing the leaves before they have unfurled in the sun long enough to win back the energy the plant used to make them. If you persist and remove leaves faster than they replace the energy then the roots get exhausted and wither away and the weed is gone.

The same goes for even deep rooted weeds such as docks, comfrey, horseradish, thistles and so on. However if these are chopped every week they do eventually stop sprouting -and in the mean time they have brought up and made available a lot of minerals in their residues. Unfortunately for such treatments to work ALL the leaves must be removed each week. And if a plant has wide reaching roots that hide amongst others far away then the leaves it puts up there can feed the roots over where you are working in perpetuity.

This means that weeds such as ground elder, bindweed and Equisetum that come through the hedge or fence from your neighbour's garden into your beds are going to keep on coming regardless of whatever you do at your end. Apart from getting the neighbour's co-operation to kill the whole plant the only way to stop this invasion is with a trench lined with impermeable plastic sheet. And this may not work if the roots can work their way down underneath, which Equisetum usually will. In which case console yourself with the thought that if you keep removing and composting the shoots that appear in your garden eventually the weeds will have transferred all the fertility of your neighbour's garden into yours!

However with the less pernicious weeds hoeing soon establishes good control, but still this is often done the hard way. Regardless of what sort of hoe you use it must be SHARP; a hoe is a knife on the end of a stick with which you intend to cut weeds in half. It must be SHARP, and I don't mean sharp, I mean dangerously sharp, so sharp it will cut paper. Few gardeners I have met have ever sharpened their hoes at all thus they have found hoeing heavy slow and inefficient labour, perhaps to the point where they begrudged hoeing as a chore. But it need not be. Take a file or a grinder and put an edge on your hoe that you could shave with and then try it. A sharp hoe cuts through soil and weeds as if they were butter. But it gets blunt so every ten minutes or so I put the edge back with a carborundum stone I keep in my pocket. Try the same, you'll be amazed at how easy hoeing becomes.

When hoeing is mentioned in books they make a big fuss over the different sorts of hoe; the swan necked draw hoe, the Dutch hoe, and several hopeless attempts at something different. The only real differences are whether you pull or push the blade and that the pulling action of the draw hoe is more use for mounding soil around plants. Other than that it's much a matter of taste but do look for a long handle as this makes the work easier, as does a light head. A heavy head is too much work especially if it has a thick soft blade. The ideal blade is light tough and springy, in fact my best are pieces of old scythe blade riveted onto worn out hoes. Avoid stainless steel as it will not keep an edge.

The books also make a fuss about walking backwards as you hoe, apparently so you do not tread the weeds firm again. What rubbish, I work forwards and watch where I am going and where I am going to place my feet so I do not trip over or damage plants. But I do agree with their timing, it is always better to hoe when the sun is hot, the wind drying and the soil not sticky. However I hoe when I can! It's better to hoe badly in bad conditions than to leave the weeds to strengthen even more. Even just slicing off by spade a sheet of weed seedlings together with a layer of soil and inverting it at least sets them back.

Naturally if you hoe often then the weeds ought only to be seedlings and can be safely left to wither away where they fall. But if they have got bigger then they may re-root or if annuals they may still set seed if they are advanced enough. Thus it is best to rake up the larger weeds, this ought to be done after they have had a chance to wither as the raking will act like another hoeing to small weeds that were missed. The weed corpses can go straight into a good compost heap but if they are full of seeds, are pernicious and have roots, or have pests or diseases then they should be rotted under water for a month or more first (making a liquid feed for free at the same time).

One trick none of the books ever mention is winter hoeing when the soil is frozen solid. If you have a bed that is fairly smooth (not freshly dug and cloddy in other words) and there has been enough frost to make the ground solid then hoeing on a warm day just as the topmost layer melts is fantastic. With the top melted but the mass underneath frozen solid the hoe can be run through the weeds at a pace that will amaze you. Even tough weeds are dealt with easily as their roots are held so firmly in the frozen soil while their tops are sliced off.

The common alternative to hoeing is hand weeding, which usually means pulling the weeds up. This is often horrendously counter-productive. Vast amounts of valuable topsoil can be taken away with hand pulled weeds, as will be much of the root systems of your crop plants. It is not possible to pull a weed without uprooting the invisible but intertwined network of crop roots that are enmeshed with it. Untold damage is done to crops by people sincerely working away pulling up all the weeds. Far better if while pulling they use a sharp knife in the other hand to sever the roots at soil level, true some weeds will re-sprout but better that than ripping up the crop's roots wholesale.

Likewise an onion hoe, which is a small hand held draw hoe, is often recommended for hand weeding tasks, and if truly sharp will be nearly as useful as a good knife. But ironically the one crop it should never be used on is onions as the root system is so close to the soil surface and the plants are so easily damaged that no iron tool should ever go near them. Although I carefully hand weed with a knife while the onions are young once they are nearly mature I prefer to leave those few later weeds to grow rather than risk upsetting the onions. In fact they then do little harm as they take up spare nitrogen and moisture and force the onions to ripen more thoroughly.

There is a very good alternative to hand weeding or hoeing and that is the use of a flame gun. These are like super plumber's blowtorches and can be powered by paraffin or gas. They kill by cooking the weeds not by burning them. The flame is passed over the weed leaves at speed and the damaged leaves (which change colour from light to dark green in the process) then wither and weaken the weeds which usually expire, though the toughest may re-sprout once or twice and need a second application. Obviously this method is most useful on empty ground as the flame can easily damage crop plants as well, but it is possible to flame between tough plants such as mature brassicas or Swedes.

A flame gun is of course ideal for pre-emergent weed control after sowing. If the crop takes say a fortnight to germinate then weeds emerging before then can be eliminated by a treatment say twelve days after sowing. Or before a crop such as asparagus has commenced into growth the surface can be cleared of weeds with impunity. Likewise a flame gun is perfect for cooking weed seeds left on the surface after clearing a weed hiding crop such as peas.

However the dangers of a large flame are not inconsiderable. Thus although I used to recommend flame guns now I prefer safer alternatives. On the small scale a hobby gas blowtorch is effective for hand weeding. These are smaller and take more time but are inherently safer. The electric hot air paint strippers sold in hardware stores are superb and providing you have a safe outdoor electric supply are a modern way to cook weeds. Safer still, but more cumbersome, is to use a steam wallpaper stripper. This takes longer to wither weeds as the steam is not as hot as a flame, indeed a steam iron can be used to eradicate weeds. (-watch out for your partner catching you though) And simplest of all for a minor weed problem- just pour boiling water on them!