Cleaning milkweed seed

As concern for monarch populations grows, so does the need for milkweed seed.  I never thought we would harvest and clean common milkweed seed but there is a need that we can easily fill because it grows happily in our pasture.  This is how we do it:

  1. Harvest pods: I don’t even look at a milkweed plant until I see one of the pods fluffing out or opening.  We gently pry the pod open a bit to see if the seed is brown.  If so we pick it and let it dry in the open, on a tarp or in a shallow container.  If the pod hasn’t opened on its own the seed can easily mold if left in a closed container, even if it’s paper.


    Common milkweed seed drying on a tarp in the far back corner



Shucking? milkweed pods with a shop vac

2. After the milkweed has dried a week or so depending on your humidity, it should be ready to vacuum.  We use a 5.5 hp shop vac but that doesn’t mean it’s the only one that will work.  After vacuuming all the loose seed, I hold the pods of common milkweed and suck the seed out.  Depending on the species of milkweed being cleaned, the pods swirling in the drum may damage the seed.  It’s ok if a few pods fly up the hose but I don’t vacuum pods off the tarp.


Milkweed seed filaments attached to the vacuum filter and on top of seed in the bottom of the drum.

3. Depending on the vacuum’s capacity, it will need to be cleaned out when you hear the motor straining.  It also varies with the number of pods sucked into the drum.  The seed fluff will adhere to the filter and the seed will be in the bottom of the drum.

4. Always sweep or pull the filaments off the vacuum filter when emptying the drum.  We have an old fashioned whisk broom to clean our vacuum filters but there may be better tools.  Then I screen the seed to remove fluff and broken seed.

5. This may not be the best way to clean small lots of seed where you don’t want to damage any seed at all.  My assumption is that some seed is immature and disintegrates in the shop vac.  We have seed dedicated shop vacuums at the farm and at home because we have found they are very useful when cleaning seed attached to a pappus.  Many of the asters fall into this category.  It took about two hours to clean 15 gallons of pods from start to finish and we ended up with about a gallon of seed.


Swamp milkweed seed after vacuuming the pods, these do not damage the seed swirling inside the drum like common milkweed pods can.


screening seed after vacuuming: pods scalped off by coarse screen, broken bits fall through a fine screen


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