This is reprinted with a thank you to http://www.sundialseed.com. I love this information…
Your weeds are here because of what’s going on in the soil.Every wild weed that sprouts in and around your garden is growing there in response to the current conditions in your soil.
If your soil is rich in nitrogen, you might see Chicory showing up on the scene. If your soil is low in fertility you might see yarrow popping its head out to condition the soil.
You can use this information from the weeds as you would a soil test to help you work with your soil.
The weeds themselves are processing these soil imbalances in an attempt to amend and balance the profile of the soil towards a climax ecosystem. We can read these weed signs and help the natural process on its way in our gardening.
We compiled this table of Weed plants and their associated soil conditions that might be at play.
Weed Plant | Indicates possible Soil Condition |
Amaranth | Rich soil, high in nitrogen |
Bindweed | Compacted soil |
Chicory | Rich, sweet soil high Nitrogen |
Chickweed | Rich, sweet soil high Nitrogen |
Groundsel | Rich soil |
Crabgrass | Soil depleted of nutrients and low in calcium |
Dandelions | Poor soil, low in calcium & high in potassium |
Dock | Wet, poorly drained soil |
Goldenrod | Wet, poorly drained soil |
Henbit | High nitrogen |
Knapweed | Rich soil high in potassium |
Knotweed | Compact ground |
Lamb’s quarters | Rich soil, high in nitrogen |
Little blue-stem | Dry sandy soil depleted of nutrients |
Moss | Soggy acidic soil low in nutrients |
Common mullein | Low fertility & possibly soil too acidic |
Mustard | Dry sandy soil high in phosphorus |
Common wood sorrel | Low Calcium |
Oxalis (Wood Sorrel) | Low calcium and high magnesium |
Ox-eye daisy | Low fertility in acidic, possibly soggy, soil with poor fertility |
Pearly everlasting | Acidic soil low in nutrients |
Peppergrass | Sweet soil |
Plantain | Compacted sour soil with low fertility and often indicates heavy clay or garden path areas |
Purslane | Rich soil, high phosphorus |
Quack grass | Heavy clay or compacted soil |
Queen Anne’s lace | Poor dry sweet soil |
Ragweed | Low fertility |
Sensitive fern | Poorly drained soil low in nutrients |
Sweet fern | Sandy acidic soil |
Stinging nettle | Rich acidic soil |
Sheep sorrel | Acidic soil low in nitrogen, dry sour sandy soil, low in calcium |
Yarrow | Poor dry sandy soil with poor fertility, low in potassium |