Earthworms are an indicator of biological life in the soil, large and small. Easily visible and easy to count, higher numbers can be an indicator of improved soil health.
The earthworm count is included for benchmarking & analysis in the Soilmentor Regen Platform.
Want to learn to identify the 3 types of earthworms? Learn how to identify the three earthworm types here, and why counting different types is important. This earthworm guide from AHDB is also helpful.
It is best to count earthworms in early Autumn or late Spring. Avoid counting worms during extreme weather conditions, or in the few weeks after a manure/compost application.
What to record
- Number of earthworms
- Make notes: type of earthworms (if you know this!)
- Digging spade
- Tray / bin bag
How to do the test
Hand Sort Method
1. Locate your chosen sample site – you can use the GPS mapping feature on the app to do this if you’ve recorded the sample locations previously.
2. Dig down to 20 cm, to make a hole of approx 20 x 20 x 20cm.
3. Place the dug up soil on the plastic bag
4. Break down the soil with your hands, keep any earthworms you find on the bag. Put all broken down soil back in the hole.
5. Count the number of earthworms and record in the app.
6. You can stop there and press ‘save’ in the app…Or…
7. You can next separate the earthworms into adults and juveniles, putting the juveniles back in the hole.
8. Count the number of leaf-litter, top-soil and deep earthworms and record the number of each type in the ‘notes’ section below where you entered the total number of worms, and ‘save’.
9. Put all earthworms back in the hole.
Alternative: Mustard extraction method
What to record
- Number of Earthworms
- Make notes: Type of Earthworms (If you know this!)
- Quadrat (177cm pipe/rope) – 0.25m2
- Mustard water (pre-mixed, night before)
- Bin bag
How to prepare the mustard solution
- Fill a 1.5l bottle half full of warm water
- Measure a tablespoon (15g) of English mustard powder
- Using a funnel, pour the mustard powder into the bottle
- Mix the solution thoroughly
- Fill the 1.5l bottle the rest of the way with warm water
- Let sit overnight
1.Place quadrat on ground
2. Remove leaf litter/cut-away excess grass growth
3. Pour half bottle (~750Ml) of mustard solution over the ground within the quadrat
4. Remove worms as they emerge, place on plastic bag
5. Wait a couple of minutes or so
6. Repeat step 3
7. Remove all remaining worms
8. Record the total number of worms collected
9. Put all earthworms back!