Workshop at the Garden To Table Silicon Valley

First I explained  the procedure of preparing a slide, magnification, some other technical aspects and then started checking the samples. Volunteers were able to see all the microorganisms in real-time on the laptop connected to the microscope camera  – that was exciting! 

We looked at 6 samples: garden soil, vermicompost (2), a mix of soil and free compost (if I remember correctly), potting soil, and compost made in a tumbler. Some samples were very dry or not collected properly and didn’t have much life. All samples had very little or no fungi except for the vermicompost that was made from dried leaves and green garden waste – it had more fungal strands than other samples, but no nematodes and very few protozoa. 

One sample really stood out – 2 bacterial feeding nematodes (which is pretty good for 1:10 dilution – est. 400 nematodes per gram); higher trophic level predators (1 enchytraeid, a couple of microarthropods) indicating abundance of lower trophic groups; diverse protozoa (testate amoeba of different shapes and sizes, some flagellates); some fungi. That was compost from food scraps made in a tumbler! It is hard to say if it was a biocomplete compost without calculating biomassess and numbers. I would want to see a fungal strand in every 2nd or 3rd field of view, but it wasn’t the case. The low amount of fungi was most likely because of the frequent rotating the tumbler as fungi don’t like to be disturbed. I didn’t find any anaerobic bacteria, ciliates or any other signs of reduced oxygen conditions even though it was overwatered the night before and we could clearly see water shining on the material. So that was a good learning experience for me!

There weren’t any anaerobes in other samples as well (except one ciliate in the moist vermicompost). Overall compost samples had more microorganisms than soil samples.

And of course nematodes were “the stars of the show” – it was exciting to watch them moving, and they even caught attention of other people on the farm. We didn’t find any fungal feeding or predatory nematodes though, only bacterial feeders.