How to grow the best weeds: till the soil, use chemical fertilizers, pesticides & herbicides. All these practices kill most of the microbial life in the soil. What will remain is dirt–just the mineral content plus some bacteria. Nature’s way of healing disturbed soil is to grow weeds. They are pioneer plants that quickly sprout from long dormant seeds left in the soil. Bacteria dominated soil is the ideal environment for weeds. Everything else will suffer and be weak and susceptible to disease organisms. Weeds are the first stage in what is called the succession of plants. Usually, weeds are annuals, and as they die back each year they add organic matter to the dirt and begin the process of building soil. The USDA says it takes a hundred years to build an inch of soil. That is only true if we continue bad gardening practices. An inch of soil can take a fraction of that time if we return biology to the soil using compost, compost tea and properly manage the soil.
How to grow brassicas (cole crops): Increase the fungal component in the soil. The weeds will begin to suffer because that is not their ideal soil balance. Brassicas want a little bacteria, a little fungus, protozoa and other soil life. All but bacteria are killed by the pesticides and the salts in chemical fertilizers. Soil fungus is chopped up and destroyed by tilling. Instead, add thermal compost to the soil to inoculate it with beneficial soil life. Thermal compost heats to >131°F consistently. This kills pathogens and weed seeds. Running scraps through a worm bin kills pathogens as they are digested by the worms, but the weed seeds remain.
How to grow grass and row crops: Increase the fungal component even more. Weeds will be very unhappy and can no longer compete. Now it is the weeds that are susceptible to disease organisms and will die. Weed seeds will have a hard time even sprouting.
To grow shrubs: Even more fungal components. Add plenty of wood chips as mulch.
To grow trees: More fungal components still. Add wood chips as mulch. Work at inoculating beneficial fungus into the soil. The white spider-web like fungal growth is the beneficial fungus. Disease-causing fungus are typically too small to see with the naked eye.
The following video shows a garden transformed from sand/clay into rich soil to a 26″ depth simply by applying wood chips on the pathways over an 8 year period. Wood chips encourage fungal growth. Earthworms and other soil organisms work the biology deep into the soil.