This information can help you decide what to plant where. Some weeds may contain medicinal value for topical application or ingestion. (Eg. weed’s root, stem, leaves, flowers)
The clues below relate to weeds that grow on their own. – Not planned planting /farming.
Amaranth – grows in rich soil, high in nitrogen.
Chickweed – and chicory like rich soil—high in nitrogen—and will grow well in alkaline, compacted soil.
Dandelions indicate poor soil that is low in calcium, but high in potassium.
Lambs quarters indicate rich soil, high in nitrogen.
Oxalis, or wood sorrel, indicates low calcium and high magnesium.
Plantain weed – grows in compacted, sour soil with low fertility and often indicates heavy clay.
Purslane prefers rich soil and is an indicator of high phosphorus.
Stinging nettle (Urtica dioica) grows in rich, acidic soil.