The old saying ‘One year’s seed, seven years weeds’ is close to the truth. Always slash weeds before they reach the flowering stage. Make sure compost heaps are well constructed so that they reach sufficiently high temperatures (60°C) to kill weed seeds.
Weed seeds require light in order to germinate.
Minimise conventional digging which brings more weed seeds to the light and triggers another round of weed growth. Instead, use mulches wherever possible. Place a thick layer of light-excluding compost over garden beds and plant into the compost. Moist soil containing plenty of organic matter is constantly dug and enriched by large numbers of earthworms.
No-dig gardens use light-excluding old carpeting, cardboard, or thick wadges of newspaper laid on the ground as a base on which to build a sandwich of hay, lucerne and compost. Just top up the layers annually for a virtually weed-free garden. Use a backyard landscaping idea from organic farmers and grow a dense cover crop such as annual rye, to act as a living mulch, suppressing weeds, contributing fertility, and retaining moisture. When ready to plant, simply spray with acetic acid herbicide.
Where a severe perennial weed infestation exists in a garden plot, cover the area with heavy black polythene, anchor securely around the sides, and leave for 12 months.