Rather than fixating on eliminating weeds from your garden altogether, why not look at the ways that a controlled use of weeds can benefit your garden!
The following list is put together with information from the following books: "Weeds: Guardians of Our Soil" and "Soul of the Soil"
1. Bring minerals, especially those that have been depleted, up from the subsoil to the topsoil and make them available to crops.
2. When used in crop rotation they break up hardpans and allow subsequent crop roots to feed deeply.
3. Fiberise and condition the soil to provide a good environment for the minute but important animal and plant life that make any soil productive (i.e. bacteria, fungus, nematode, protazoa, earthworms).
4. They can be good indicators of soil condition, both as to variety of weed present and to condition of the individual plant. Certain weeds appear when certain deficiencies occur:
-Convolvulus (bindweed) indicates a hardpan, or a crusty surface
-Chickweed- indicates tilled or cultivated soil with high fertility, but if stunted and small it indicates low fertility
-Dandelion indicates heavy clay soil that’s been tilled or cultivated, acid or low lime soil especially
-Dock, indicates waterlogged or poorly drained soil, acid or low lime
-Lambs Quarters- High humus, fertile unless stunted or pale
-Nettle- tilled or cultivated, often acidic or low lime
-California thistle- indicates heavy clay soil
-Shepherds purse- saline soil
-Mallow- cultivated soil
-Fat Hen- cultivated
-yarrow- low potassium indicator
5. Retain moisture. Deep divers create pathways in the soil for capillary action. As ground cover they reduce evaporation. Keep ground moist and enable the less hardy, surface feeding crops to withstand drought better than the crop could alone.
6. As companion crops – planted alongside your crops – they enable other plants to get their roots to otherwise inaccessible food.
7. As direct compost. Weeds store up minerals and nutrients that would be washed, blown or leached away from bare ground and keep them readily available. Also encourage balance of micro-organisms which are main storage facility for soil nutrients.
8. Weeds make good eating, for humans and for livestock. Many of the common weeds are good for eating (and when medicinal uses are considered, MOST weeds are valuable for consumption).
9. Weeds can be used as a living mulch. Protect soil from erosion, wind and heavy rain.
10. Defer pests from your crops as fodder and habitat for predators.