A Winogradsky column is a simple way to grow diverse microbes from mud in a transparent container. Over several weeks, microbes form colorful layers that reveal differences in metabolism, oxygen tolerance, and nutrient use, providing a living model of microbial communities.

1. Collect mud and water from a pond, river, or other natural source using a bucket or container.
2. Cut newspaper into small pieces to serve as a carbon source.
3. Mix mud with egg yolk (sulfur source) and newspaper in a bowl. Optional additions: leaves, bark, straw, or salts.
4. Fill a tall clear jar or bottle one-quarter full with the mud mixture.
5. Add plain mud until the jar is three-quarters full.
6. Pour water on top until almost full, leaving a small air gap.
7. Cover with plastic wrap secured by a rubber band (not airtight, as gases will be produced).
8. Place in sunlight or under a lamp for 4–8 weeks.
9. Observe as colorful microbial layers develop over time. Record changes with photos.

Winogradsky Column Experiment - Boys & Girls Club of Greater Lowell:

How to Build a Winogradsky Column - Humanoidity:

📄 A window into the microbial world: the Winogradsky column - Joyful Microbe: https://joyfulmicrobe.com/winogradsky-column/

• Set up multiple columns with mud from different locations to compare microbial communities.
• Add different materials (metal, shells, salts, or plant matter) to test how nutrients influence growth.
• Vary light exposure or temperature to see how conditions affect microbial patterns.
• Use a microscope to examine samples taken from different layers.

• Wash hands thoroughly after handling mud or column contents.
• Do not open the column indoors once microbes are established; gases may build up and odors can be unpleasant.
• Dispose of columns outdoors by emptying into soil after observation.
• Supervise children during setup and handling to avoid spills.

• Why do different microbial communities form in layers in the column? (Because microbes grow where oxygen, light, and nutrients best suit their metabolism.)
• What colors appear, and what do they suggest about the microbes present? (Purple/green bands often indicate photosynthetic bacteria; black layers indicate sulfate-reducing bacteria.)
• How does adding materials like leaves or metal change the community? (They provide new nutrients or electron acceptors that select for different microbes.)
• Why did Sergei Winogradsky develop this method? (To study microbes in communities rather than in isolation.)
• How does a Winogradsky column model natural ecosystems like wetlands or sediments? (It shows stratification and interactions among microbes that also occur in nature.)