The use of weed killers is an effective method of killing. You can apply weed killers to large areas and this is especially useful when you have tougher perennial weeds or weeds with long tap roots. Most weed killers need active green growth to work as it is through the contact with the leaves that it is able to enter the plant’s system and destroy its structure. Weed killers can be purchased as a concentrate or ready-mixed for smaller areas of spot spraying. They come primarily with three actions – selective, non selective and pre-emergent.
Selective will only kill the weeds that it has been blended for – the type of weeds that it kills will be shown on the bottle. These types of herbicides are commonly used on lawns where they will kill broadleaf weeds but not the grass. Non-selective herbicides will damage everything the spray touches, even desirable plants in the garden, so special care must be taken to prevent spray drift. Pre-emergent is often used over large areas of paving or cobblestones. Once applied, it acts as a film, coating the soil, so that weeds can’t grow through this barrier. These weed killers can last from 9-12 months.
Mulch acts as a protective cover over soil. It supresses weed growth and retains soil moisture to keep roots cool and moist over the hot summer months. By mulching, you prevent weeds from establishing themselves. Weed seeds will germinate beneath mulch, but will be unable to reach sunlight to grow. Organic mulch can be in the form of peat, compost, shredded newspaper, sawdust, pea or barley straw, seaweed, wood chips, bark or lawn clippings - basically any organic material that will break down into the soil.
Apply the mulch in a layer at least 50mm thick to effectively eliminate weeds. Organic mulch has the added advantage of improving soil structure as it breaks down into the soil. Apply organic mulch to the soil in spring and again in autumn. Weed mat is an inorganic mulch that still allows air and moisture in to the soil while excluding the light. Weed mat is best applied to the areas once it is free of weeds. It can be covered with bark, pebbles or crushed shell.
Always follow the manufacturers instruction as to the mixing and use of the chemicals. Exceeding the recommended dose could damage the foliage. Don’t invent a brew by mixing chemicals together. If you can’t read the name of the chemical any more – don’t use it, old chemicals should not be used - like most things they have a shelf life and will become ineffective with age. Keep a set of mixing and measuring tools just for mixing chemicals – store them safely away from children. Wear protective clothing, PVC gloves and a respiratory mask when spraying and mixing chemicals. Spraying in windy conditions is ineffective - wind causes spray to drift to plants you don’t want to kill and gives a spotty coverage. Keep separate sprayers – one for your weed killers and one for insecticide.