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The Roving Microscope – Fieldnotes #2

Danielle's wormery

‘Good compost has per teaspoon 1 billion bacteria, 400 to 900 feet of fungal hyphae, 10,000 to 50,000 protozoa and 30 to 300 nematodes. Compost can inoculate, maintain, or alter a soil food web in a given area.’

Jeff Lowenfels and Wayne Lewis, Teaming with Microbes – A Gardener’s Guide to the Soil Food Web (Portland, Oregan: Timber Press, 2010), p. 131.

There are three basic shapes of bacteria represented in this sample taken from Danielle’s wormery: coccus (round or oval); bascillus (rod-shaped); and spiral (corkscrew).

A microscope image of an amoeba surrounded by bacteria (magnified x 400)

The large roundish organism on the left is an amoeba, the hundreds of assorted round and rod-shaped organisms are bacteria.

A microscope image of a nematode (magnified x 100)

This worm-like organism is a nematode – it looks like a fungal feeder. The dark clumps are the organic matter, and there are lots and lots of bacteria across the whole slide, which is a sign of healthy compost.

A microscope image of a spirilla bacteria (magnified x 400)

The corkscrew shape running top to bottom is a pathogen. This is not a good sign; it is most likely an indicator that the compost is too wet and starting to become anaerobic. The best thing to do in this situation is to oxygenate the compost by adding shredded paper or cardboard, which will soak up the excess moisture. The worms need oxygen, so adding some paper will help. The large brownish clumps are organic material. Many cocci bacteria (round or oval) and bacillus bacteria (rod-shaped) are visible.

A microscope image of a testate amoeba (magnified x 400)

The large organism in the centre of the image is a testate amoeba. It makes a shell called a test from debris, which provides a shelter for the amoeba inside and protects it from predators. You can see that it is feeding on bacteria. On its left is another amoeba, which is also feeding on the surrounding smaller bacteria. The dark circle below is a spore, an indicator of fungi or mould. This is normal and presents no problem for vermicomposting.

A microscope image of a testate amoeba surrounded by cocci and bacillus bacteria (magnified x 100)

The larger organisms are testate amoebae, who are busy feeding. The presence of so many cocci and bacillus bacteria indicates that the vermicompost is healthy.

A microscope image of a cheese mite

A microscope image of a cheese mite (magnified x 100)

These images are an added extra; they do not come from Danielle's compost. This is a cheese mite taken from the rind of some cheese. It looks enormous through the microscope, but is invisible to the naked eye – quite a shocker!

If you compost and want to take part in a home composting experiment, you’ll need:

  • a selection of identical compostable or biodegradable items (see list below)
  • a net bag and clip to securely close it (see guidance below)
  • a plastic milk bottle cap (or similar) and permanent marker pen to identify your items

If you do not use a composter but you're interested in finding out more, please see our Composting Processes page for more information.

1. Choose your experiment items

Select the type and quantity of compostable or biodegradable plastic items from our list that you would like to test. Please only select items that display the following manufacturer information:

  • 'compostable' (only)
  • 'home biodegradable'
  • 'home compostable'
  • 'suitable for home composting'
  • TUV OK Compost 'HOME' certification mark
  • Din Certco 'HOME COMPOSTABLE' certification mark

NOTE: If testing multiple items together please ensure they are an identical type and brand (one type and brand of item per net bag).

2. Prepare your experiment equipment

To make locating your experiment items in your compost easier, please compost your items in a plastic net bag (the kind of net bag used to hold fruit in a supermarket would be ideal). Use a permanent marker pen to identify your items on a plastic milk bottle cap (or similar) and add to your net bag. To test fruit and veg stickers please stick each label on a plastic milk bottle cap first then add to your net bag. Use a permanent marker pen to identify them. You will have the option to upload photographs of your composter and experiment equipment to help us analyse your results. See our Photography Guidelines for more information.

NOTE: Please ensure you use a perforated net bag. This is so a sufficient flow of oxygen, organic waste and microorganisms can come into contact with your experiment items.

3. Create a login account

Create a login account and share a few extra details about what composter you will be using for the experiment, its location in the UK for our Live Composting Map, and your composting method. Please set the duration of your experiment according to how long it usually takes you to make compost. There is the option to share photos of your composter and experiment items and equipment, if you wish. Please indicate on your form if you would like to share your images on the Big Compost Experiment website. See our Photography Guidelines for more information.

4. Start your experiment

Securely close the net bag containing your experiment items and identifying markers and add to your composter. Carry on composting as usual. We'll send you an email reminder when your experiment is due to finish and it's time to look for your net bag and items.

5. Submit your results

When your experiment timer has finished, please look for the net bag and items in your compost. You can use a trowel, spade or household sieve to locate it. Under 18s must be accompanied by a responsible adult. Check the contents of your net bag for any traces of your items. If there are any traces please compare them with our 'Scale of Degradation' in the results form in your login account and share any other useful observations about your experiment. There is the option to share a photo of your results. Please indicate on your form if you would like to share your image(s) on the Big Compost Experiment website. See our Photography Guidelines for more information.

NOTE: Once you have completed your experiment, please dispose of any item remains in your general waste collection. Check locally for recylability of other experiment equipment and rinse before recycling.

How to take a photograph of your experiment equipment

Pre- and post-composted items and equipment

  1. Place your biodegradable or compostable items on a clean surface alongside any secondary packaging (if applicable) and net bag. A contrasting surface is preferable (i.e. one on which the items will stand out).
  2. Orientate items and packaging (if applicable) in order to capture any compostable labelling or certification marks (if displayed). If testing multiple items together please ensure they are an identical type and brand (one type/brand of item per net bag).
  3. Position your camera approximately 1 metre above the objects. Position items clearly within the viewfinder of your camera or camera phone, so that all edges of items are visible. Please ensure no recognisable features (people, faces, house number, etc.) are visible in the image.
  4. Take a photograph (while keeping your hand steady!)
  5. Upload photographs via your login account, with the option to display them on our Gallery page.