Trying to collect milkweed (or other seeds with attached filaments aka parasols) so you can plant them elsewhere while preventing unwanted volunteers, but the darn things keep blowing away or sticking to your fingers? This collector works as a vacuum to hold your seeds.
Milkweed plants are beneficial to a wide variety of insects, especially the monarch butterfly, which depends on it for food for the larvae. The larvae benefit because they pick up a toxin from the milkweed that helps protect them against predators. As a result, we get the beautiful migration of monarchs, which have suffered in recent years due to loss of habitat and food. I'm collecting milkweed to spread throughout my community.
Step 1: Find a Computer Fan
Pull a computer fan from a scrap pile or purchase from an electronics store. It should be DC-powered and easy to hold (mine is about 3.5" wide). It may have any number of wires. Using a 9V battery or arrangement of smaller ones such as AA, connect the wires until you find the right ones to turn on the fan (extra wires are control wires used by the computer). Note the direction of the fan. You may be able to reverse the fan by switching the wires, but no big deal if that doesn't work.
Step 2: If Necessary, Add a Grill to the Exhaust Side of the Fan
In my case, the exhaust side of the fan had large openings that put my fingers at risk due to exposure to the blades. I cut a sheet of masonite with openings and superglued it to the exhaust side (did not have the right size of nuts and bolts for the holes I made).
Step 3: Build the Case
This step can be done a number of ways, including wood, metal, plastic, and 3-D printing. I used masonite I had on hand. I cut the pieces about 4" deep and such that they overlap at the corners, with the rough side of the masonite facing out so seeds slide better inside. The joints were reinforced with short sections of wood pieces while allowing room for the fan to fit in snug on the bottom. Test fit over the fan and reinforce joints with extra glue. Allow to dry for at least 2 hours.
Step 4: Add Screen
Cut a piece of metal screen (plastic flexes too much) to fit the intake side of the fan. Test fit in case.
Step 5: Add Notch and Battery Holder
To side of case add notch for wires and a means of holding the battery. As you can see, I just used some small pieces of cut wood and twist tie for the battery.
Step 6: Add Battery Terminal
Although one of the previous steps show a terminal connected to the battery via tape (a result of not taking pictures at the right time), this is the best time to add the terminal because you can put the fan in the case and cut wires at the right length to minimize redundant wire. Since the voltage is low, any tape is okay as long as wires are isolated (I also added a third piece of tape to secure the unused white wire).
Step 7: Test It!
Put the fan and screen in the case, hook up the battery, and feel the air rushing through! This works great for a good number of bunches of milkweed, but suction does drop after a while, necessitating disconnecting the battery to dump the seeds.