The best way to learn about your soil's health is to get a soil test through your local cooperative extension service or at a local nursery. However, there are a few simple things you can do to get a general idea about your soil's health. One of the best ways to find out more about your soil is to observe what's growing well in it.Different weeds thrive in different conditions. Note that we're not talking about one or two weeds here. If you're seeing several of the same weed in an area, that can give you a good general idea of what type of conditions you have in that spot. Here are some common weeds to look for, and what their presence means. Where possible, I've linked to a photo of the weed so you can identify them more easily.
Weeds, and What They Mean
- Bindweed: This morning glory relative, a vining plant with white and pink blossoms, thrives in compacted soil.
- Chickweed: This low, spreading annual weed is a sign of high fertility.
- Chicory: Chicory is most easily identifiable by its bright blue flowers. You'll often find this plant growing along roadsides, where it is a sign of compacted soil.
- Dandelion: Probably the most easily identified weed on this list, the dandelion is common just about everywhere but will absolutely thrive in acidic soil.
- Henbane: Henbane, also called "black henbane," is common in the northwestern U.S. as well as southern Canada. It is a sign of alkaline soil.
- Horsetail: This perennial weed, which spreads both by spores and rhizomes, thrives in damp, poorly-drained soils.
- Lamb's Quarters: Lamb's quarters are very common annual garden weeds. Their presence in your garden is a sign of high fertility. Of course, you could just go ahead and harvest it; lamb's quarters are edible and very high in nutrition.
- Plantain: There are several different types of plantains, from round-leaved varieties to lanceleaf plantains that have foliage that resembles thick grass. In either case, if they're flourishing in your garden, that's a sign that you have low soil fertility.
- Purslane: Purslane's thick, fleshy leaves are actually edible and a very good source of omega-3 fatty acids, iron, and calcium. If it's thriving in your garden, you likely have soil that is high in fertility.
- Quackgrass: This grassy weed, which is a perennial that spreads via rhizomes and suppresses the growth of other plants with its chemical secretions, is a sign of compacted soil.
- Red Clover: I have a hard time calling this a "weed," since clover is so beneficial to pollinators, but I know plenty of people who consider it to be one. If it's thriving in your garden, it's a sign that your soil is high in fertility.
Fixing Soil Problems
If the type of weeds you have in your garden are a sign of high fertility, consider putting a flower or vegetable garden in that area -- the plants will likely grow well in that spot.
For other areas, have your soil tested to get a complete prescription for improving the fertility, texture, or pH in that area.
I'm always stressing the importance of observation in the garden. This is one of those ways just observing what's growing and thriving can help you learn more about the health of your garden.