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seed storage
Re: the question on storing seeds in wet tropics:
Here are some notes sent to me by Pauline Mullins, director of an seed
preservation program in Texas, US. She first asked if these are indigenous
plants (which I assume they are not, since their seeds are rotting in the
natural environment), and if not, why not? She suggested the J. L. Hudson
catalog from California, US as a good resource for tropical plant seeds. Some of
her notes are general in nature:
-- Dont store [seeds] in airtight jars if they arent properly dried.
-- If seeds are dried, then rehydrated, then dried again, it lowers their
longevity and viability.
-- Keep seeds in the coolest area (near the floor).
-- Maybe [seeds] that have a high hard seed content would store well since
hard seed resist rehydration [seeds such as okra, some cowpeas (lots of legumes,
actually), etc. form seeds which are very slow to reabsorb moisture after they
have once been dried, an adaptation to dry conditions and so perhaps not overly
cogent in this context...JR].
-- [Seeds] with hard, shiny outsides seem to resist molding. Some of these
need scarification at planting time [nick seed coats on side away from
hilum...JR].
-- A way to dry the seeds might be to gently dry them (solar box cooker).
They would need to use thermometers to keep seeds from getting hotter than about
100 degrees F [50 C = 102 F]. They could then store in glass jars or tins.
-- They could find out what local plants have leaves or roots with
anti-fungal properties. For storing okra seeds, for instance, they could keep
them in their pods and layer in jars with the leaves or roots. Do they have any
eucalypts? This technique might also protect against insects. The anti-fungal
plants could be ground into powder for dusting, or used as a tea/dip after
initial cleaning of seeds before drying.
Jack: Seeds should never be dried below 3% - 7% (depending on the seeds)
or raised over about 118 F (about 58 C) for long if they are to be used for
planting. Long-term seed viability increases as storage moisture content
decreases below 20%, down to the 3% - 7% mentioned, at which point vigor begins
to fall quickly. Seeds can absorb between 20% - 30% moisture in 90% humidity
(!). Viability = % of seeds which germinate, longevity = for how long; vigor
refers to the seedlings.
Re: Dan H. -- Sea salt would probably work great, even ignoring its
Calcium chloride content, if dried thoroughly before use. If moisture could
reach the seeds in storage, however, salt would soak itself AND the seeds by
absorbing moisture from air... ECHO -- an interesting organization, does some
neat stuff in the tropics, Russia (urban rooftop gardens on 6 of compost), etc.
They have a fairly considerable seed bank and will share with projects such as
the one described.