A weed is really anything that grows where it is not wanted. Weeds are fast-growing, invasive and tend to compete with cultivated plants for food and water. Weeding is critical to a healthy garden and is undoubtedly the least glamorous job, and often overlooked from season to season.
Generally, weeds can be classed as either annual (for example Wild Oats) that complete their life cycle within one year, or perennial (such as Privet or Wandering Jew) that persist from year to year. This will help to determine the type of control method to be used.
Having an understanding of how weeds propagate will also help to determine the type of control method to be used. For example, Wandering Jew takes root at every node along the stem and creeps along the ground whereas others like Oxalis and Onion weed propagate from bulbs deep in the soil and unless you dig up every bulb, they will pop up time and again. Farmer's Friend is an annual that produces alot of seed and easily spreads from garden to garden. Lantana and Privet are nasty hard-wooded perennial weeds whose seed is spread by birds. In large quantities, it is easier to poison than to pull them out. The common Sow Thistle is another annual and is spread by wind blown seed making it very difficult to contain.
- Hand weeding can be a practical method of removing weeds from flower beds and vegetable patches without the potentially harmful effects of chemicals.
- The most effective time to weed is when they are small or before they seed. Place weeds in a plastic bag and leave in the sun to dry for a few weeks before adding them to your compost.
- When removing perennials, be careful not to leave roots, bulbs, rhizomes, tubers or thick tap roots because they will shoot again.
- Using specially designed hand tools can make weeding much easier, particularly when you are weeding out clumpy plants like Curled Dock.
- Be careful when using chemical control. If applied incorrectly or carelessly, it can be dangerous to plants and risky to animals or children.
- The safest way to apply the most commonly used garden herbicide Glyphosate is with a weed wand allowing you to target the chemical only where it is needed. Glyphosate virtually kills any plant and is systemic, absorbing into the plant's sap stream. Applying a small amount to just a few leaves will be enough to kill the whole plant (a few drops of food dye will help you see where you have been).
Spraying may be necessary when you need a blanket coverage over a large area. Always wear protective clothing including long sleeves, long pants, a mask, boots and rubber gloves. Avoid spraying on windy days and always read the use and storage instructions on the packaging.
The best cure is prevention. Good basic gardening practice such as mulching will avoid creating an environment for weeds.
Mulching smothers weeds and deprives them of light which is their most important life source. Mulch can be in the form of dead leaves, composted wood waste or newspaper. Apply it to a depth of atleast 10cm and be sure to keep it away from the main trunk of any other plants.
Other methods of alleviating weeds is to grow ground covering plants such as Peruvian Lily.
Another environmentally friendly solution is soil solarisation, the process of killing weeds and weed seedlings with high temperatures. Moisten soil and spread a layer of thick plastic or something similar to cover a garden bed. The plastic sheet creates a greenhouse effect by trapping solar energy and preventing heat loss. This heat increases soil temperatures to a point which will usually kill all types of weeds.