Harvesting milkweed seeds

In hopes of continuing to increase the quantities of milkweed in the yard, I have been gathering seed this fall from the following varieties of milkweed:

Asclepias incarnata in bloom
(left lower corner)

Swamp Milkweed (aka Red Milkweed or Marsh Milkweed) Asclepias incarnata Sun: Full  Soil: Sand,Loam,Clay  Moisture: Moist,Wet  Height: 3'-5'  Bloom Time: Jun-Jul  Color: red,pink  Root: Fibrous  Zone: 4  Spacing: 1'-18"   Red Milkweed attracts butterflies of all kinds and the leaves are a preferred food source for the Monarch Caterpillar. Asclepias incarnata thrives along ponds, streams and detention basins. It preferes moist soil but also does wel in average, well-drained garden sites. Full sun is best and some light shade is tolerated. No butterfly garden is complete without Red Milkweed, also known as Swamp Milkweed or Marsh Milkweed. Zones 3 - 9. Butterflyweed Asclepias tuberosa Sun: Full  Soil: Sand,Loam  Moisture: Dry,Medium  Height: 2'-3'  Bloom Time: Jun-Aug  Color: orange  Root: Taproot  Zone: 4  Spacing: 1'-18"   True to its name, Butterflyweed (Asclepias tuberosa) attracts legions of butterflies, and is an important larval food source for Monarchs. Look for their beautiful chrysalises on your plants! This rugged plant thrives in dry soil to well-drained loam. Makes a fantastic cut flower! Hardy to Zones 3 - 10. Despite having scattered common milkweed seeds in the native plant bed,  I didn't note any of the common milkweed this summer. Common Milkweed Asclepias syriaca   Sun: Full,Partial Soil: Sand,Loam,Clay Moisture: Dry,Medium Height: 2'-4' Bloom Time: Jun-Aug Color: lavender Root: Zone: 3 Spacing: 1' This favorite of the Monarch butterfly produces a profusion of sweet-scented lavender flowers in mid-summer. The caterpillars feast on the leaves, stocking up for the day when they will become butterflies and migrate to Mexico for the winter. Grows readily from seed, and thrives in almost any well-drained soil, even tough clay or dry sand. Spreads rapidly by rhizomes, and is best planted in large areas with other grasses and flowers. Grows two to four feet tall. Hardy to Zones 3 - 8. Milkweed pods within a given population or production stand ripen over a period of a few to several weeks and a subset of them will likely be ready for collection each day during that time. Due to the wind-aided dispersal of milkweed seeds, the window of opportunity for harvesting mature seed from any individual pod can be narrow. Seed capture bags, made from a variety of materials, can be affixed over maturing pods and retrieved at a later date. Using these bags can give a seed collector several days of flexibility in scheduling a return visit. Also, rubber bands or cable ties can be applied to the widest part of nearly mature pods, to prevent them from fully dehiscing. As compared to seed capture bags, rubber bands and zip ties are lower cost and less conspicuous, but their use may only extend the collection window by a couple of days. Once the pods are thoroughly dry, the seeds can be separated from the coma, or silk-like ballooning material.  Try stripping the seeds and coma from the pods into a paper bag. Shake the contents of the bag vigorously to separate the seeds from the coma and then cut a small hole in a corner of the bottom of the bag and shake out the seeds. Store dried seeds in a cool, dry place protected from mice and insects (a recloseable plastic bag or container in the refrigerator works well.) In preparation for spring planting, seeds should be vernalized (given cold treatment) to increase the germination rate. The best way to give the required vernalization is through stratification. To stratify seeds place them in cold, moist potting soil (sterilized soil is best but is not required) in a dark place for several weeks or months. Since most people prefer not to place potting soil in their refrigerators, an alternative is to place the seeds between moist paper towels in a plastic bag where there are fewer fungi and bacteria available to attack the seeds. After a vernalization period of 3-6 weeks, the seeds can be planted in warm (70˚F), moist soil.  Even after vernalization / stratification, seeds of many plant species will not germinate. In these cases, the seed coats appear to require action by physical or chemical agents to break down or abrade the seed coat. "Scarification" with some type of physical abrasion that breaks the seed coat can be accomplished by placing the seeds in a container with coarse sand and shaking the container for a 30 seconds or so. Scarification may be required for some milkweeds (e.g., A. viridiflora and A. latifolia) and might improve the germination rates of other species.