Tips on Weed Control

Clearing the ground of garden weeds

Forking and removing weeds

tips on weed control Forking out the roots of weeds is most successful on a small plot containing annuals and tap-rooted perennials. It enables the area to be cleared for immediate planting. Creeping weeds and shallow-rooted perennials can also be cleared fairly easily in this way. Forking is much easier if the soil is light; never attempt it when the soil is wet and sticky or baked hard.

Digging and burying weeds

Turning over the soil with a spade and burying weeds and their roots is a good method for clearing a small plot containing annuals or creeping and shallow-rooted perennials. You can clear old pastures or lawns in this way, even if they contains couch grass. It is hard work, but it means you can plant immediately and the turf will decay to provide nutrients.

The deeper the turf is buried the better — it should be dug down at least 15cm (6in), so this is not a suitable method if you have a thin topsoil. Subsoil and topsoil should not be mixed.

Rotavating

A rotavator has tines which chop up the surface layer of the soil. Rotavating can successfully clear annual and most perennial weeds, except those that are very deep-rooted. However, a single rotavation can make the weed problem worse, as individual pieces of chopped-up root and stem will regrow and thus multiply. To kill them, the ground must be rotavated several times during the growing season. After the initial pass, wait two or three weeks for the root fragments to sprout, then rotavate again. Repeat until the roots eventually become weak and exhausted.

Rotavating for weed control is most effective in dry weather and on light soils. Adjust the rotavator and tine speed so that the weed roots are chopped up as finely as possible. One disadvantage is that rotavating damages the soil structure and can cause a pan. If possible, sow an extensive rooting green manure such as grazing rye (see Green Manuring and Green Manure Crops) after the last rotavation to help restore the soil structure.

Mulching

One of the best methods of clearing weedy ground is to use a mulch to exclude the light. If weeds are kept in the dark when growing the roots will eventually become exhausted and die. Suitable mulches include carpet, cardboard, newspaper and black plastic.

To be effective, the mulches must be in place when the weeds are trying to grow. Lac, them in spring, just as growth is beginning. Prepare the area by cutting down all the tall weeds and grass with a strimmer, mower, sickle or shears. Small amounts of debris can be left on the surface of the ground. Remove very bulky material to the compost heap and put down the mulch.

Black polythene

Use 400-500 gauge (100-125 micron) polythene. This will last up to three years and can be reused. Bu ry the edges 7.5-10cm (3-4in) in the soil with a spade. On a large area, use a few bricks, logs or sandbags to keep the plastic flat and cover any joins.

Cardboard

Use the largest sheets that you can find. Overlap them 10-15cm (4-6in) where they join. Use bricks, pieces of wood or thick wads of straw to hold them in place. This mulch should last several months.

Carpet

Use hessian-backed wool carpet held down with wire pegs made by bending 25cm (10in) lengths of stout wire. If necessary, use a stout nail and hammer to make holes in the carpet. Most carpets will start to let weeds through after one growing season, but good-quality ones can last longer. Remove the carpet before it decays as dyes and persistent pesticides are often used in the manufacture of carpets.

Newspaper

Use a minimum thickness of one whole newspaper opened out and overlap the sheets well. Cover with a 5-10cm (2-4in) layer of hay, straw or grass mowings to hold the paper down. This will suppress most weeds for a month or two.


Period of mulching

The period of mulching depends on the weeds. Annual weeds need to be mulched for only one or two months, creeping weeds, turf weeds and shallow-rooted perennials such as couch will be killed or considerably weakened after one growing season, while deep-rooted perennials and weeds with bulbils will need more than one growing season and will be killed or weakened in two. To finish clearing a patch of weakened weeds, simply fork it over.

It is often possible to use the ground even while it is being cleared because widely spaced, vigorous vegetables such as Brussels sprouts will push up through a light-excluding mulch, as can fruit bushes and shrubs. This practice is most likely to be successful where weeds are not rampant – in old pastures or lawns, for instance -or where the weeds have already been partly eliminated by forking or digging.

However, it is not a good idea to grow crops on very weedy ground as plant growth can be affected by the decomposition of the weeds. Also, vigorous weeds such as bindweed grow up to the light and may poke through the planting holes.

02. February 2011 by Dave Pinkney
Categories: Organic Gardening, Weed Control | Tags: , , , | Comments Off on Tips on Weed Control

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