Seed Saving

At the end of each season, the strongest/healthiest plants are left to continue their life-cycle and produce seed for next year's crop. The following process was performed on a single plant to begin to gather data on seed yields. This plant was originally germinated in May, 2015 and the dry seed heads were harvested in November of the same season. This plant was grown in Los Angeles, CA, in a very large container, irrigated in full sun.

Dried Seed Heads

Handful of Indigo Seed Heads Persicaria Tinctoria.jpeg
This handful of dried seed heads was gathered from a single plant in the fall of 2015.

The flowers of the Persicaria Tinctoria plant typically range from magenta to peach to ivory in color. When dried, the floral petals that surround each seed turned a pale beige and became very brittle.

In each flower, a seed

Single Dry Seed Head Indigo Persicaria Tinctoria.jpeg

Peeking from within the dried flowers, the individual indigo seeds are visible, smooth surfaced, dark brown in color.

Dried and Brittle

Crushed Seed Head Persicaria TInctoria.jpeg
This seed head was hung upside down for two weeks and dried after being cut from the plant. The material feels dry and the coating around the seeds crumbles with a light roll between the fingers.

Stripping the Seeds from the rest of the plant

Lightly Crushed Seed Heads with Some Leaves.jpeg
By rolling the seed heads between the hands, the seeds, as well as some leaves and stalks, can be separated from the rest of the dried plant matter.

Further Removing the Seed Coating

Finely Crushed Dry Seed Matter Indigo.jpeg

The resulting mix of dried flower material, leaf bits, seeds and stalk sections can be rolled between the palms for five minutes or until the mix consists of seeds and chunks of matter that are smaller than then seeds themselves. By grabbing a handful of the mix, rubbing between the hands and allowing it to fall after agitation back into a pile, the non-seed material was slowly and consistently broken down into finer particles.

Still a mix of materials

Seeds and Chaff Indigo Polygonum Tinctorum.jpeg

The resulting mix is composed of tiny, light leaf matter, bits of stalk, decomposed floral petals and seeds, some including embryos and some without. The empty seeds are typically lighter in color, weight and are hollow.

Using a fan to winnow

The mixture of seeds and debris is sprinkled in front of a fan blowing just above the top of two separate plastic bins laid out in the direction of the airflow to catch the seeds and smaller bits as they fall. With the fan set on low, the mix is slowly shaken so that it passes in front of the fan, the lighter particles are blown further away, the heavier items fall straight down. Seeds are more dense than leaf matter and will fall directly into the first bin, the lightest material will be blown a considerable distance away and the rest of the material will fall into the second bin away from the fan.
Two Bucket Winnowing System.jpeg

Examples of Separated Material

Separated Indigo Seeds and Leaf Stem Sheath Matter.jpeg

The right hand pile is composed almost entirely of seeds, with some heavier pieces of stalk that can easily be picked out. The pile on the left is composed of the material blown further from the first bin, it is made up mostly of leaves, empty seeds, smaller bits of stalk, etc.

Potential for Gleaning

Indigo Seeds and Chaff.jpeg

Even within the discard pile, there are still some viable seeds. Further passes in front of the fan can separate them from the chaff.

Total yield from one plant

Separated Indigo Seeds Persicaria Tinctoria.jpeg

Once separated from the other matter, the seeds can be weighed. This one plant yielded 13.0 grams, which is approximately 6,500 seeds. The seeds can be packaged and stored in a cool dry place to be germinated in the future.