How to control the weeds in your garden


Weeds get in the way of enjoying our gardens. They are simply life on earth trying to 'be', and I suppose they could be regarded as a testament to irrepressible 'life force' (known by some as DNA!). But most of us would be a lot happier without them.

We can never win the battle with weeds, but we can reduce their impact to very low levels.

How we manage weeds depends on how dry the climate we live in is, how big our vegetable garden or orchard is, how much time we have, what tools are available to us, and what leeway we have to do what needs to be done when it most needs doing.

Managing a vegetable garden is different from managing a yard full of fruit trees which is different from managing a lifestyle orchard. So we will consider these separately.

This page is written to help home food gardeners, and practices are quite different to those relevant to commercial garden and orchards.

It is also written with the assumption that most of us would prefer to use the chemicals known to be very safe, from a human health point of view.

The most important thing to bear in mind is that there is no one thing that will 'do it' for every unique garden situation. Usually, a combination of strategies works best.

General Principles

Managing weeds in the veggie garden

Most of us are summer gardeners. This means that the veggie patch is often left over winter, and becomes a weed patch - nature abhors a vacuum.
In spring, the choice is between 'digging the weeds in' or spraying them out. Which works for you depends on several things.
First, your belief about sprays. The best herbicide to use from the point of view of a home gardener looking to be certain to effectively kill all the different kind of weeds AND have no risk to personal health is to use a glyphosate weed killer (the best known brand at this time is 'Roundup' produced by Monsanto). This appears to be a practically safe chemical when used as recommended.
Second, whether or not spraying will endanger adjacent plants. Glyphosate may be very safe as far as humans are concerned, but it is deadly to plants. If there are precious plants hard up against the veggie plot, then you run the risk of damaging or killing them if you spray close by.
Third, timing. Often, today's the day. The day on which the veggie garden has to go in. You buy your transplants and fertilizer, dig the garden so the weeds are buried, put in your plants-job done.
Fourth, improving the soil. Few of us are blessed with light, free draining, fertile sandy, peaty, or volcanic loams. Mostly, we have to dig in lime, dig in peat, dig in compost, and physically break up the soil to improve the drainage. Establishing a new veggie garden
Using glyphosate is a very good option, and often the only realistic option, for clearing an area of lawn or weeds for a new veggie patch.

Preparing an existing veggie garden for spring planting
For those of use who are primarily summer gardeners, glyphosate is a very good option for 'cleaning up' the existing veggie patch in preparation for the new season. This is especially important where there are weeds such couch grass and kikuyu grass which spread by underground rhizomes.
The most effective method in warm temperate and warmer areas is to spray out once in winter, and again when the first flush of spring weeds emerge, just prior to the big spring plant-up. This prevents winter seeding weeds making their deposit!

Spraying between rows of vegetables
Possible, but not for the faint hearted! Glyphosate is dangerous to all plants, and it doesn't distinguish between friend and foe. Lapse of concentration, sudden gusts of wind, 'bounce' and carelessness can cause you to damage or kill the produce of which you are so justifiably proud. This is high risk territory - almost irresistible to males, in other words! In our opinion, glyphosate is too risky to use as a between row weeder in a home garden of mixed veggies. There are, as always, exceptions. For crops which have waxy, water repellent coatings on the leaves, such as cabbages, broccoli, other brassicas and crambe, you can often get away with spraying between the rows WITH a spray guard, USING a lower rate, and WITH GREAT CARE.

First, on available evidence, there is no risk to human health, immediate or carcinogenic, from using glyphosate in the ordinary manner. And probably not even when used at much higher dosage. It works on a plant specific enzyme system, and seems to be well proven as safe for animals when used on weeds.
The real risk is what is euphemistically called 'collateral damage'. That is, plants you love and hold dear get a drift of glyphosate and are severely damaged or die. This can be caused by 'the bounce',  'drift', 'the drip' or carelessness.

To repeat, between row spraying with glyphosate in the home veggie garden is a high risk activity, and you really have to have killed a few plants and had had quite some experience to know what can and can't get away with. It is not recommended for any but the most experienced. The winter/spring spray-outs are safe as long as risks are minimized- Benefits Hoeing is extremely effective when the surface of the soil has dried out a little, the hoe is sharp, and the rows straight. Hoeing works best in a mulch free environment, perhaps as a follow up to a sprayed out 'no dig' type garden.
A small garden knife - preferably with the handle painted bright red so it doesn't get lost (!) - has to be used to clean up the weeds close in to the stems of the plants where it is too risky to hoe.

The best time to hoe is when the latest crop of weeds are at the small seedling stage, and the day is sunny and/or windy. Conversely, the worst time is when the soil is moist, the weather rainy, and the weeds well advanced.

The twin dangers of hoeing are-

  1. risk taking-hoeing too close to the plants in the row and felling the work of weeks in the blink of an eye!
  2. careless or inattentive hoe sharpening and slicing your finger open
The best type of hoe is the one whose blade runs just under the surface of the soil, neatly severing weeds at the soil line. The most critical aspect is buying a hoe whose blade is adjusted so that you can stand fairly upright as you work. A hoe with the blade attached at the wrong angle, or with too short a handle, will force you to bend over as you hoe, causing unnecessary back strain. Mulching is an excellent option where you can lay your hands on a sufficient quantity of material. It is excellent to put on after spraying the garden out for the summer crop because it suppresses summer weed seed germination AND conserves water.

Types of mulch

 All these materials can be used under young home orchard trees. The bark of young trees is suceptible to spray damage until it thickens up. Propietary plastic sleeves are useful to prevent damage.
A real problem spraying under the canopy of young trees can be solved by using homemade or propietary 'weedmats' to suppress weeds right up to the trunk, at the same time conserving moisture. One product is made from sheeps wool, and eventually breaks down, but not before the young tree has become well established in a weed free environment.

Non Chemical Weed Control in Home Gardens- J Mississippi State University publication 1580, a brief fact sheet discussing general principals.

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