Winter Sowing
ReSeeding RI sows native, collected dry clean seeds in moist soil in plug trays from November through February. A small number of our species do not require “cold stratification”, exposure to moist and cold temperatures in the range of 40°F and below, to break seed dormancy and germinate in the spring, but most native species in our climate zone germinate well when winter sown.
We fill 21 and 50 plug trays with a Pro-MiX HP Mycorrhizae, a balanced peat-based soil mix that encourages seedlings to produce root systems. A thin top layer of bio365 Biostart, a soil consisting mainly of peat moss, coconut coir, and perlite and fertilizer, is added.
Two or three seeds are sown per plug. The seeds, of most of our species, are sown at a depth slightly more than the length of the seed. Some seeds, such as common yarrow, which require light to germinate, are placed on the surface of the soil. Species with hard outer coatings, such as Indian grass, benefit from “scarification”, scratching or etching the surface to permit more water absorption and speed up germination. We rub these seeds gently with sandpaper before sowing. Find the specific germination requirements for the seeds of ReSeeding species on our species pages.
A sprinkling of fine sand on top of each cell ensures proper seed contact with the growing medium. Trays are watered and labeled with the species’ name and the unique collection identification number that correlates to the date and origin of each seed collection.
Cold Frames
We place our seeded plug trays into cold frames for the winter. These frames are 8 feet by 4 feet and 20 inches high.
The bottom and top of each frame has galvanized hardware wire to keep out rodents. A piece of landscape fabric is placed under each frame to deter unwanted plant material growing within the cold frames.
Attached to each cold frame is a large piece of overwintering plastic. This plastic sheet is 50-60% opaque and blocks UV rays. It also helps to maintain constant temperature and moisture inside the frames to keep the seed plug trays cold and moist throughout the winter. In the spring, the plastic helps speed up growth as temperatures increase.
Plug Distribution
Once our plugs, or small plants, have a strong root system and healthy foliage, they are distributed to our foundation plots.
Each foundation plot receives approximately 200 plugs of a species. These plots are maintained by our partner growers. Seeds harvested from the plants in these foundations plots provide the next generation of ecotypic seed!
Winter sowing your own native plants?
Tips for Winter Sowing
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- Uniformly spread seeds thinly on the top of medium.
- Lightly cover seeds with fine sand (many seeds need light to germinate).
- Protect seeds from rodents.
- Make sure seeds are receiving uniform moisture, including during the winter.
- Utilize overwintering film and or domes to protect seed/seedlings from adverse weather.
- Monitor seeds/seedlings throughout the growing season.
- Provide nutrition, such as diluted fish emulsion, when applicable.
Wild Seed Project’s “How to Grow from Seed” offers excellent comprehesive information.
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