Great Organic Weed Control Options
In organic farming getting rid weeds can be a challenge.
Results of our research into methods of weed contol for organic farms and urban organic backyard farming have revealed this important principle:
GROW STRONGER PLANTS
Stronger plants are better able to compete effectively with weeds and are less attractive to pests and diseases too.
Grow stronger plants by:
- Building better soils:
Correcting soil imbalances and building soil fertility and life through composting, mulching, aeration, adequate irrigation and other methods gradually tips the scale in favor of your garden plants.
What are weeds really?
Weeds are nature’s way of improving soil conditions.
They thrive in areas in need of help with problems like compaction, mineral imbalances and water-logging – areas where most other things don’t grow well.
In organic farming getting rid weeds is also removing their healing functions, that you then must assume responsibility for if your land is to flourish.
Nature is patient, but if you don’t have time to wait around for decades, then jump in and take decisive steps to boost your soils yourself.
Alternatively, take persistent weeds as a sign that the area is not suitable for horticulture, and pick a better area to base your garden on.
- Using better plants:
Many of the plants you trial in the early years of establishing your small organic farm or urban organic backyard farming will not be ideally suited to your unique conditions. Therefore, it makes sense to trial many species and varieties – those that thrive… will thrive, and those that don’t will tend to become extinct on your property! Eventually you’ll end up with a robust farm system of the most competitive crop cultivars. These will more readily outperform weeds.
In the vegetable garden, try out different non-hybrid heirloom varieties. Create continuous improvement by leaving your best performing plants to set seed. In this way you will gradually evolve your own special genotypes ideally adapted to your special conditions of climate and soil. The pay-off in resistance to drought, pests and diseases will be worth the time and trouble!
Sustainable weed control then is essentially about continuous improvement of your organic gardening system. Your worst weed problems will therefore occur early in the establishment of your system. As it matures, weeds should become less of a problem.
ORGANIC WEED CONTROL OPTIONS
In the meantime, aside from the fundamental principles of better soils and better plants, there are many weed control options available. Aside from resorting to a home-made organic weed killer, our research into methods of weed contol for organic farms and urban organic backyard farming came up with a wide range of options.
The best results come from using a combination of these strategies:
For some weeds, removal by pulling the plant out, roots and all, is the only practical option. Care must be taken to remove the whole plant with bulbous weeds that can regrow from corms such as Cape Tulip. Onion grass is another one that can only effectively be removed by pulling the whole plant out (though you could get chickens to do this for you by erecting a chook house over the spot and leaving them to it for a year).
Cultivation, or tilling the soil, should be done sparingly on all but the most fertile and life-rich (i.e. resilient) soils. This is because it disrupts the soil’s structure – both the natural layering that places the richest organic matter (and soil life) at the more highly aerated surface, and also the fungal hyphae and plant roots that hold the soil together and give it a beneficial crumb structure.
Cultivation exposes soil life to the damaging effects of sun, climate and wind. Such exposed soil is also more vulnerable to erosion by rain and wind. Bare soil is akin to an open wound on the Earth, so cultivate sparingly, and mulch or sow immediately to effect rapid healing!
A Dutch Hoe is a useful manual tool for weeding. It has a long handle at the end of which is a sharp blade that can be run just under the soil surface, separating target plants from their roots. Soil structure is not dramatically disturbed, which makes it a good option.
Another strategy in organic farming for getting rid of weeds is to let animals do it for you! This is the
Permaculture approach: it conserves system energy (human, herbicidal or machine energy not needed) while optimizing yields. Pigs or chickens will enjoy the opportunity to indulge in their natural tilling behavior, while utilizing weeds as food to grow you meat or eggs.
Mulching deters plant growth by blocking access to sunlight. Really vigorous plants will be able to grow their way through all but the thickest mulches, so it is most effective where established weeds have already been removed.
Mulch materials that eventually break down to form compost in your garden include straw (e.g. wheat or barley straw), grass clippings, shredded paper, peanut shells, and wood chips.
The best decomposing mulches will be those that add balanced nutrient to your soil. Materials like wheat or barley straw, or shredded paper on their own are very high in carbon. Bacteria breaking it down will have to rob nitrogen from your soil to complete the process.
It makes sense, then, to blend in some high nitrogen materials to such mulches, such as pea or Lucerne hay, or sprinkled in chicken manure or diluted urine.
There are some plants that furnish living mulch. These are known as smother crops (e.g. nasturtium, sweet potato). Thickly sown clover (White Dutch Clover is good) or alfalfa (Lucerne) amongst your fruit trees or vegetables will allow little room for weeds, while adding valuable nitrogen to the soil. Lippia is another nitrogen fixing plant that grows vigorously in summer to form a dense lawn.
Highly effective sheet mulch can also be made from many throw-away materials including newspaper,
large sheets of cardboard, old carpet and under-felt (if not treated by chemicals). It is a good strategy for reclaiming lawn areas for vegetable growing.
To get a crop while waiting for the mulch to smother the weeds, plant potatoes into holes made here and there in the sheet mulch and cover the lot with straw. The spuds will be formed on top of the paper, making for easy harvest and keeping them nice and clean.
Another particularly effective – but rather drastic – sheet mulching technique is the use of black plastic sheeting. Slash the weeds, sprinkle with bird manure, and cover with black plastic for a few weeks. The weeds “grow themselves to death”. However, the black plastic limits airflow to the soil, and should only be considered as a last resort for truly intractable weed problems.
Most weeds are annual plants that germinate and grow at a predictable time of year. Growing suitable crops during the weeds’ “off-season” is a useful technique to minimize weed problems.
Unlike other irrigation methods, drip irrigation delivers water exactly where it is needed – to your desirable plants. Such precise water delivery selectively nurtures your crops while denying water to weeds.
Burning converts surface plant material such as seeds and foliage to ash and carbon dioxide (a greenhouse gas). Plant material that could have been utilized to build your soils is thus lost.
Weed seeds from surrounding areas can be swept by wind onto the ash bed, often leading to worse weed problems the following season.
A variation on the burning technique is the use of a blow torch or special hot foam dispenser. The hot foam holds its heat on the target plant just long enough to kill, using less energy than the blow torch method. Commercial organic growers often use these methods.
A better alternative to burning is to “top” weeds before their seeds ripen. This just means cutting off the high seed bearing parts of the plant. The advantages of topping are:
- The plant material can be used e.g. as compost, mulch or fodder (unlike burning).
- The roots and therefore the soil are not disturbed (unlike pulling weeds out or cultivating)
Depending on the season, many weeds will regrow seeds and effective control will mean you’ll have to top them again. Topping can be achieved mechanically by mowing or slashing (or, in the vegetable garden, cutting the weed off at ground level with a pair of scissors).
Depending on the weeds and their state of growth, you may also be able to use grazing animals to “top” them for you – such as sheep, goats, geese, muscovy ducks or cattle.
Goats are particularly good for removing blackberry (they love it!). Geese and Muscovies make great lawnmowers (and mobile fertilizer factories) to keep weeds down at lawn level, especially when still lush and green. Cattle are well suited to deal with long (“rank”) grass, while sheep do better on short pastures.
A key part of pasture management is to rotate your livestock through a series of small paddocks, each heavily grazed for a short period. This effectively prevents them from only eating their “favourites” and leaving the weeds to flourish and take over.
Some livestock varieties are less fussy, and thus better than others at eating out the weeds – Dorper sheep for example will reportedly eat Patersons Curse, while Merinos and British Breeds won’t (unless starving).
Some plants produce substances that suppress the germination of other plants. A mulch of mow killed grain rye prevents weed germination but does not harm transplanted tomatoes, broccoli, or many other vegetables.
Tagetes minuta (Mexican Marigold) enriches and cleanses the soil when grown near woody plants (shrubs and fruit trees) while strongly suppressing the germination of annuals such as weeds – good preparation for subsequent vegetable crops.
If a particular weed is proving resistant to all your efforts, it’s because the land really needs the healing that nature has sent it in to do. You can help speed up the process by using a homeopathic approach. In homeopathy the fundamental adage is “like cures like”, and in the case of weeds, if the land wants what the weed has to offer, then lay it on!
Here is how you do it: Start by collecting up all the weeds you can find, roots and all. Then there are three ways you can go from there:
The first option is to burn the weeds, and collect the ash. The second is to juice the weeds and collect the juice. The third is to steep the weeds for a few weeks in water to make a liquid manure.
Take the results of whatever option appealed the most, and dilute it (say 50 parts water to one part ash or juice. For the liquid manure, follow the instructions on our webpage dedicated to the subject). Then spray the diluted concoction onto your weed infested land.
DESIGN A WEED BEATING GARDEN LAYOUT
Another way of beating weeds (especially lawn) is via sensible design that minimizes the borders you have to defend against their ingress.
Lots of small vegetable beds means heaps of surface area for weeds to invade into. Better to combine them into one, bordered by driveway, pathway, paving, fence or wall to further reduce the length of perimeter that is vulnerable to invasion. Once weeds have been cleared from the area, it’s a lot easier, with good design, to keep them from becoming a major problem.
Some plants act as a natural barrier to weeds through shading or by forming dense low hedges with tightly packed roots. Nasturtium, comfrey, lemongrass or arrowroot can be utilized as a soft hedge around weed and lawn areas to form a barrier to their spread.
Planting a windbreak against strong summer breezes, or along your boundary with your neighbor’s weed infested property, can also help to reduce otherwise huge influxes of wind blown weed seeds.
So you can see there are a lot of tools available in organic farming for getting rid of weeds. But it pays to always tolerate a few as they add to the biodiversity and thus resilience of your garden system.