The "bin method" for collecting milkweed

No doubt your caterpillars are eating prodigious quantities of milkweed!  Here's how to collect milkweed stems efficiently.

Take a large plastic bin with high sides, and line the bottom with small deli containers (32 oz suggested), each filled with about 2" of water.

The bin will keep the milkweed stems upright and prevents the water from spilling into your car.

If you don't have enough milkweed locally, go to the edge of town along a country road.  The shoulders are mowed mid-summer, causing milkweed stems to grow back as more tender shoots.  You can spot them as usually the tallest plants on the mowed shoulders.  Find a good clump--you can fill your bin in just a few minutes.  Avoid milkweed growing near crops because studies show it can have lethal levels of pesticide.  Milkweed grown in partial shade is the best quality early in September.

After gathering, use the bin to disinfect your milkweed and kill spiders all at once.  Mix 9 parts water to 1 part bleach (sodium hypochlorite ~ 7%), and soak for 5 minutes, with occasional agitation.  Rinse with tap water.  You can refrigerate extra milkweed to keep it fresh.

Disinfecting the milkweed is optional.  If you don't disinfect, then you need to inspect each stem to eliminate spiders (only if your caterpillars are small).

If caterpillars are larger than 1/2-3/4 inch, they can find their own way in half a day to a fresh milkweed stalk you lean against an old one.  The exception is when the milkweed is dried with leaves curled up.  In that case, you need to cut each leaf from the old stalk, unfurl the dried leaf, and hand-remove any caterpillars.

Sometimes when feeding new milkweed, the caterpillars get lost in the spent milkweed and are thrown out.  Two remedies...

• Put the old stems in a small bin and don't discard them for several days.  Any caterpillars you left by accident on the old stems will climb up to the top where you can see them.

1. Keep a count of how many caterpillars you found while feeding.  Mark the count on a small piece of paper and tape it to the bin.  Next time you feed them, make sure you transfer the same number of caterpillars.  If one is missing, then look for it in the old milkweed.

Be careful not to rub your eyes after handling milkweed.