How to Grow Mold on Bread for a Science Experiment

Learn how to safely grow mold on bread with your kids for an educational science experiment about microorganisms.

  1. What You'll Need. Gather these simple materials: several slices of bread (white bread works best), clear plastic bags or containers with lids, water in a spray bottle, labels and markers, magnifying glass (optional), and disposable gloves for handling. Choose a location where the experiment can sit undisturbed for 1-2 weeks, away from food preparation areas.
  2. Setting Up Your Experiment. Start by having your kids make predictions about what will happen. Place each bread slice in a separate container or bag. Create different conditions: leave one slice dry as a control, lightly mist another with water, place one in a warm area, and put another in a cool spot. You can also try adding a small piece of cheese or fruit to one container to introduce more spores. Label each container clearly with the date and conditions. Seal the containers but don't make them completely airtight - mold needs some air circulation.
  3. Observing and Recording Results. Check your bread daily and have your kids draw or photograph what they see. Start a simple chart to track changes in color, texture, and growth patterns. Most mold will begin appearing within 3-5 days. Look for fuzzy growths in colors like green, blue, white, or black. Discuss why some pieces grow mold faster than others, connecting observations to concepts like moisture, temperature, and air circulation. Never open the containers once mold appears.
  4. Safety and Disposal. Always wear gloves when handling the experiment and never open containers once mold is visible. Keep the experiment away from family members who have asthma, allergies, or immune system concerns. Some people are sensitive to mold spores even in small amounts. When the experiment is complete (after 1-2 weeks), dispose of everything - bread and containers - in the outside trash. Wash hands thoroughly afterward and clean the experiment area with a disinfectant.