(Continued from Part 1.)
The first step in processing harvested seeds is to remove them from whatever the plant has stored them in. Many seeds are encased in small dry seed pods, or fine seed heads, either of which can be rubbed between your hands to separate the seeds out. This creates a lot of dust and detritus which must be removed by using some of the equipment mentioned above or other various methods. Larger dry pods, like beans and peas, can often be opened and the seeds easily stripped out while the pods are tossed aside.
Seeds from many fleshy-fruited plants such as cucumbers, tomatoes, and squash can be removed with some of the pulp, soaked in water for 48 hours, then more easily separated out. Using this fermentation method can kill many of the pathogens tomatoes are prone to, but not all.
A large portion of the seeds I collect require screens for separating the chaff from the seeds. When using screens, sometimes the seed falls through, sometimes the chaff falls through leaving the seeds on top, and sometimes a little of both. It depends on what kind of seed you are working with and the more experience you get, the better idea you’ll have of which methods and screens to use for each seed type.
Some Seed Cleaning Examples
Following are some examples of each seed-cleaning method I use.
The first example uses buckwheat. Buckwheat has a fairly large angular seed, slightly smaller than a pea. They are easily harvested by grabbing handfuls of dry material from the tops of the plants and putting them into the harvest bucket. When I have enough to process, I reach into the bucket and roll everything between my hands until the seeds are more or less separated from the stems. Photo 6 shows what they look like after I finish this process. You’ll notice there are large pieces of chaff, seeds, and lots of finer particles of dust and detritus.
PHOTO 6 – Buckwheat After Collecting
Photo 7 demonstrates what happens as the buckwheat passes through two different screens. Using the ⅛” mesh first (A) all the dust and small detritus is removed. The seeds and larger chaff remain on top of the ⅛” screen (B), then most of the chaff is left behind when the seeds are sifted through the ¼” mesh (C). The majority of the chaff is removed leaving 98% clean seed.
PHOTO 7 – Buckwheat Processing
Photo 8 shows some of the stages of amaranthus collecting and processing. The amaranthus I grow is a seed grain smaller than quinoa, but there are many ornamental varieties as well. It has two special problems. First, the seeds fall out of the heads very easily, and second, they don’t all ripen at once. Normally with this and lambsquarter (quinoa’s sibling) I go out to the garden and shake the heads into a bucket to harvest that day’s mature seeds, then return a few days later to repeat the process. This particular amaranthus (A) was a volunteer plant that needed to be harvested all at once so the burn pile could be lit.
To keep the seeds from falling out, the heads were carefully held upright and then tilted over into the bucket (B). Since most of the seeds were not yet adequately dry and therefore stuck in the seed heads, the broken-apart heads were left in the bucket to dry for a week (C), receiving daily rubbings to remove any seeds which were dry enough. Once the branches of the seed head were completely dry, they were rubbed together one last time and everything dumped into a tray. By swishing the tray back and forth while tilted, the chaff rises to the top and the heavier seeds settle to the bottom of the tray (D). This “swishing” is similar to panning for gold and works well with many seeds.
If you’re okay with getting only 80-90% of the seeds, screens are unnecessary and the seeds and chaff can be swished so the seeds settle to the bottom, then the majority of the chaff can be removed with your fingertips. You’ll still end up with a little dust and chaff mixed in but that’s okay. In the amaranthus below (D), the seeds which have swished out will go directly to the finest screen while the rest of the chaff is rubbed again, then screened for the remaining seeds.
PHOTO 8 – Amaranthus
Many of the best herbs are in the mint family: basil, oregano, and catnip being but a few. These have very small seeds which can be difficult to separate from the chaff, but is made easier by employing a few tricks. The seeds are so small I use only the window screen. In Photo 9 catnip seeds are being processed. The larger pieces of chaff are left behind (A) but most of the dust and detritus falls through with the seeds (B). By blowing very lightly on the pile (C), most of the lightweight detritus can be blown away leaving mostly seeds behind. Based on your tolerance for chaff mixed with the seeds, the resulting pile in (D) may be good enough.
PHOTO 9 – Catnip
If you want your seed cleaner yet, put it into a bowl and use the swishing method to get more of the chaff to rise to the top where you can then blow it away to create the cleaner seed seen in Photo 10.
PHOTO 10 – Cleaner Catnip Seed
Oregano is similar to catnip but the seeds are only slightly heavier than the dust and detritus, making it more difficult to blow away. Photo 11 shows the seed stalks as they are harvested (A) and after they have been rubbed together to remove the seeds, then passed through the finest screen (B). In C you’ll notice that while much of the seed and detritus have been separated by blowing, much of the seed has remained behind.
Since most of the mint family tends to make a bazillion seeds, it’s generally not important to get every last seed. Photo 11D shows the very tiny seeds being picked up with an index card to place in the storage envelopes. As a side note, I save all the seed-cleaning remains in a single bucket, then scatter them along a nearby power line right-of-way and roadsides in front of my homestead where the plants are mostly weeds like ragweed. The seeds remaining with the chaff have a second shot at germinating and making their contribution to the world, or just feeding birds.
PHOTO 11 – Oregano
Many seeds are as small, or smaller, than the mints but have very smooth coats in comparison. Celosia, lambsquarters, and quinoa are among this group. Since the seeds are so tiny they go straight to the smallest screen and this time we’ll use the coffee can (Photos 12A & B). In C the seeds and chaff have been dumped into the coffee can where the chaff remains on top of the screen while the small seeds fall easily through. With a little bit of blowing, the remaining chaff is removed (D), forming the small pile of dust and debris shown in the red circle.
PHOTO 12 – Celosia
Photo 13 is showing celosia again, not the best example, but many seeds benefit from the more constant air flow of a small computer fan as opposed to puffing your cheeks and blowing on them. By moving the fan closer or farther away, you can regulate the speed and quantity of the air movement to get just the right amount for those trickier seeds which are only slightly heavier than the chaff.
For larger, heavier seeds with relatively lightweight chaff, a large box fan can be set up in front of the box lid shown in Photo 2C and the seed/chaff mixture dropped in front of the stream of air. The heavy seeds will fall into the box lid while the chaff is blown farther away. This works well for things like dry beans and grains which are often the same size as the chaff making screening ineffective, but the difference in weight between the two is so great the box fan works very well.
PHOTO 13 – Fan Method
(To be concluded tomorrow, in Part 3.)