Our Monarch Rearing Methods

Raising monarchs can be a beautiful and meaningful experience. But if done carelessly, it can also cause harm. That’s why we follow a set of simple but effective practices to raise monarch butterflies responsibly. These methods keep the caterpillars healthy, prevent the spread of disease, and allow us to contribute to real scientific research.

We don't raise monarchs to increase their population. If that were the goal, planting milkweed would be more effective. We raise them to create a deeper connection between people and nature. And we do it in a way that protects the species we love.

Why Responsible Rearing Matters

There’s a parasite called Ophryocystis elektroscirrha—or OE for short—that can harm monarchs. It spreads easily through spores that cling to eggs, leaves, and enclosures. Monarchs infected with OE may look fine, but they often can’t fly properly, and they don’t survive long in the wild.
If we’re not careful, rearing monarchs can actually spread this disease. That’s why our methods are focused on prevention.

Our Step-by-Step Process

1. Collect Eggs, Not Caterpillars

We only collect monarch eggs from milkweed—not caterpillars. Once a caterpillar has hatched, it may already be infected. By starting with eggs, we reduce the risk of introducing parasites into our enclosures.

2. Disinfect the Eggs and Leaves

Right after collecting the leaf with the egg on it, we disinfect both. This step is crucial.
  1. Mix a mild bleach solution: 1 tablespoon bleach in 1¼ cups water (3 to 5 percent dilution)
  2. Spray both sides of the leaf with the solution
  3. Gently rub the leaf surface to break through tiny hairs that can trap air bubbles
  4. Let the solution sit for one minute
  5. Rinse the leaf thoroughly or dip it into clean water
This process helps ensure that OE spores are removed before the egg hatches.

3. Use Clean Milkweed

Every leaf used to feed caterpillars should be disinfected the same way. Even wild milkweed can carry spores, so this step helps protect your caterpillars from getting sick.

4. Limit the Number Per Enclosure

We raise no more than 4 to 6 caterpillars in a single enclosure. This keeps things manageable and limits the risk of one sick caterpillar spreading parasites to the others.

Testing for OE Before Release

Once a butterfly emerges, we test it for OE before tagging and releasing it.
  • Use a piece of clear tape to collect scales from the butterfly’s abdomen
  • View the tape under a microscope
  • Look for OE spores and compare to known infection levels
  • Record whether it is “all clear” or infected

Tagging and Logging Data

Every monarch we raise is logged in our records before release. We document:
  • Tag ID number
  • Whether it’s infected or all clear
  • Male or female
  • Release location
  • Date and any other observations
This information is submitted to national databases and helps scientists track migration patterns and monitor health trends in the population.

Why This Matters

These practices allow us to safely enjoy the magic of raising monarchs without causing harm. They also open the door to learning about larger ecological systems, and help connect our small neighborhood to something much bigger.
By following this process, we’re not just watching butterflies grow—we’re becoming caretakers of a delicate and extraordinary cycle.

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Wilmington, DE

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