Small or medium seeded berries can be quickly and easily cleaned using a blender with dulled blades and water.
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Materials:
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Blender
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Water
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File to dull the blades
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*follow up with seed cleaning by flotation, or drying and then winnowing or sieving (see below)
After harvesting seeds, they should be laid out to dry immediately. Berries can be refrigerated until they can be processed.
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Seed anatomy is diverse and their is no question that this poses a challenge when it comes to cleaning seeds. Collecting fully ripe seed will improve cleaning methods. Here we described a few simple tools and techniques for cleaning seeds from a variety of plants. Most seeds will require at least 2 or more techniques to produce pure seed. We separate techniques here by "Processing" and "Cleaning" and processing is done first. "Cleaning conifer cones" has a separate section.
Seed Cleaning
Threshing is an ancient technique used to separate grain from plant stalks, modified a number of times over the years. This method was taken from Young and Young (1986) and used to clean dry seeds and large seeded berries.
Dried plant materials or fresh berries can be threshed.
Materials:
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Corrugated rubber mat
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Seasonally available: http://www.canadiantire.ca/en/pdp/precut-ribbed-black-runner-27-x-6-ft-0685027p.html
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Drywall paddle (or make your own)
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5 gallon bucket
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Large cardboard box base with short lip
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*follow up with seed cleaning by flotation, or drying and then winnowing or sieving (see below)
Flotation
Wet seeds, such as those from berries can be cleaned by flotation. Full seeds will sink and empty seed and pulp will float. Floating material can be poured off and discarded while the sunken material can be reserved in a sieve and set out to dry or placed into pre-treatment conditions.
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*Many seeds are meant to float and cannot be cleaned using flotation, so we recommend this technique only for berry seeds.
Seeds with long hairs such as from poplars are wind dispersed and are a bit of a challenge to clean. This method was modified from Fung and Hamel (1993) for cleaning seed from willows, fireweed, and poplars.
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Materials:
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Sieve set: mesh sizes #20, 40, 60, 140 and bottom pan.
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Shop vacuum with a 2mm netting wrapped around filter
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5 gallon bucket with lid
Cleaning
Processing
Sieving
Dried seeds mixed with chaff or materials that are a different size can be cleaned by sieving.​
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Materials:
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Sieve set: mesh sizes #5, 10, 20, 40, 60, 140 and bottom pan.
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Coarse sieves: mesh sizes approximately: 1cm, 2cm and 3cm
Winnowing
Winnowing is useful to separate seed from material that is lighter in weight.
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Materials:
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Table fan
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Sheets of newspaper
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Bowls or shallow pans
First the scales from the conifer cones must be opened to release the seed. For some species, their cones will need to be subject to extreme heat (75C) before opening. Others just need to be well dried.
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Click "Cleaning Cones" for more information or watch our seed cleaning video.
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Literature cited
Fung, M. Y. P., and B. A. Hamel. 1993. Aspen seed collection and extraction. Tree Planters’ Notes 44:98–100.
Young, J., and C. G. Young. 1986. Collecting processing and germinating seed of wildland plants. Timber Press, Portland, OR.
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Photo credit: Andrea Hanson