Weeds as soil indicators

I’ve recently taken a deep dive into weeds that I’m finding in the garden. I’ve skimmed over this subject for the last few years, but now I want to really understand why weeds are growing in my garden. Each “weed” is actually there for a reason – to bring a mineral to be used by other plants, to cure a mineral deficiency in the soil, or use long roots to open up compacted soil. Weeds have jobs and if you know how to read the weeds, you can find out more about your soil – sort of a DIY soil test with plants! I’m going to post some of my discoveries here in the next few weeks. We’ll start with Wood Sorrel.

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Oxalis stricta (common yellow wood sorrel)

This plant grows in sandy soil.  It is perennial and thrives in slightly alkaline soils with a pH of 7-8 (an indicator that we would need to work on acidifying the bed if we want to grow strawberries or spinach, which like a lower pH soil).

According to Weeds and Why They Grow (Jay L. McCaman, 1994), wood sorrel grows where there is very low calcium and phosphorus, but very high potassium and magnesium.  The flowers are visited by bees, ants, and butterflies. 

Wood sorrel is edible (in small amounts, because it contains oxalic acid) and is a source of vitamin C, and is regarded as a medicinal plant.  The yellow flowers also can be boiled to produce a yellow to orange-red dye.

Okay …. I’ll add another “weed” in the next week or so.