Butterfly Farming Articles
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Eggs & Egg Washing Technique

Melanie McCarthy & Terry Terbush

(Jan 2013 - Recipe amended for use with more concentrated bleach)

(Refer to photos at bottom of page.)


Take 200 Monarch eggs off your plants; put in fridge in airtight container until you are ready but for no longer than 7 days; take eggs out and gently drop into a strong screened coffee filter; then take all and immerse in egg wash solution.

Here is how to make the egg wash solution in undiluted form.  It is bleach and water and different butterfly farmers have experimented and use different percentages of bleach. This is what has worked for us: if using bleach with active ingredient of 8.5% - 9%: 2 cups bleach to 9 cups water. Add two or three drops of Ivory Liquid Dishwashing Detergent-- which makes the spores very slippery and they come right off. After you make up this batch of concentrated bleaching solution, when washing the eggs, dilute by using 19 parts water to one part solution (above) to make solution to wash that day's eggs. One breeder uses 1 tablespoon of the concentrated solution to 19 tablespoons of water. This gives you plenty of egg wash for one treatment.


Put your final solution into a glass bowl that will accommodate the copper colored filter with the eggs already in the filter. Turn your timer on for 7 minutes. Immerse the copper colored filter into the final wash solution. Agitate the eggs for 7 minutes, constantly. Use a turkey baster to spurt water onto the eggs which will cause a lot of agitation of the solution all over the egg, on top of the egg, the sides and the bottom. After 7 minutes remove the filter from the solution and rinse the eggs for 3 minutes each three different times in clean bowls of water. Use the same filter, the same turkey baster. For the Finale, perform the Egg Swirl.

Egg Swirl:

As you remove the coffee filter from the water (with the washed and now rinsed eggs), swirl the mixture around so that about 1/2 the eggs swirl to 1/2 of the filter and are scattered up and down the side, then turn the filter over and dunk the other half back in so that the remaining eggs swirl over the other half of the filter. Voila!

Now lay the filter down on a clean/sterile surface covered with a napkin or paper towel which will instantly begin to absorb the excess liquid, until the eggs dry. It will take about 4-6 hours for the eggs to dry enough. Then pick up the filter and tap the sides with a utensil. All the eggs drop to the bottom. No sticking or mushing of eggs! And best of all, you only use 1 tablespoon of your concentrated solution per day. Remember, the egg wash solution is concentrated so before you actually use it on your eggs, further dilute it by 19:1. 19 parts water; 1 part solution.

After the eggs are dry, pour them into a sterile (tiny) container or souffle dish, breathe on them to add some moisture back since the bleach can be drying and then cover with an airtight lid. Let them hatch out completely. Keep only the same age eggs together, do not mix eggs layed from differnt days as you want all the eggs in this vial to hatch out at the same time. When they hatch out, you can either add a leaf or two of milkweed so they can crawl onto this or better yet take a 6 oz sterile cup and stand up some milkweed in the cup. Turn over your container with the newly emerged larvae and tap on it with a heavy butter knife. All the new larvae will fall onto the milkweed in the next larger sized cup.

Egg-washing technique - illustration photo 1
Glass bowl
Egg-washing technique - illustration photo 2
Copper-colored coffee filter
Egg-washing technique - illustration photo 3
Eggs sitting in solution ready to be agitated
Egg-washing technique - illustration photo 4
Eggs being agitated with turkey baster
Egg-washing technique - illustration photo 5
Bowl with solution and turkey baster alongside
Egg-washing technique - illustration photo 6
Egg-washing technique - illustration photo 7
Eggs left in filter
Egg-washing technique - illustration photo 8
3 bowls of clean water to rinse the eggs 3 times at 3 minutes each using turkey baster
Egg-washing technique - illustration photo 9 Egg-washing technique - illustration photo 10
After the eggs are swirled around the coffee filter, they are laid onto a paper towel or napkin to dry for about 4 - 6 hours
Egg-washing technique - illustration photo 11
Tiny cup to store clean eggs


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