The idea of dry paper towel absorbing moisture is very helpful.
If you also include a small square of newsprint, it will indicate how dry the air is. It will resist stiffly or crackle if you bend it or crumple it when dry. When it is not bone-dry, it becomes limp.
You can also use dry rice as a desiccant, especially if it is very dry. You can assure that by baking it in a shallow pan until just before it turns brown. Then seal it tightly, quickly, in glass. (Hot rice may melt a plastic jar or bag.)
If daylily seeds are dessication-toleraqnt, or orefer very dry storage, you can use silica gel.
I use silica gel; in paper envelopes to keep tubs full of packets very dry. However, that's too big and ungainly for little 2"x3" Ziplocs. Maybe itg would be practical to add a tiny pinch of silica gel granules to big seeds like day lilly. The silica gel used for drying flowers is a little finer than table salt, with some dust.
But, if you use too much fresh silica gel in a tightly sealed tub or small jar, it can pull the relative humidity below optimum. Probably the best long-term cool storage moisture content is 5% to 7% (by weight) , and that is maintained by a Relative Humidity around 25% to 35%. But silica gel can pull the RH down to 10% or maybe lower if you let it!
That's no problem in a Ziploc, since humidity can diffuse right through thin plastic. It can probably move through the "zipper" even easier!
I bought some humidity-indicating cards with indicating spots for 10% - 20% - 30% - 40% - 50% & 60%.
I'd rather have had 5% steps from 5% to 20%, then 30% and 40%.
humidity cards - 40 cents each from Drierite: https://secure.drierite.com/ca...
ULINE seems to have a $70 minimum order for these! But only 18 cents each?
INSTRUCTIONS FOR DRYING SEED
Regenerate silica gel in the oven at 250F for 3-4 hours (not hotter).
Long term seed preservation:
the risk of selecting inadequate containers is very high
Dept. Biología Vegetal, Escuela T. S. Ing. Agrónomos. Universidad Politécnica de Madrid. 28040 - Madrid. Spain.
E-mail: [email protected]
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Diaz, O., Gustafsson, M. and Astley, D. (1997). Effect of regeneration procedures on genetic diversity in Brassica napus and B. rapa as estimated by isozyme analysis. Genetic Resources and Crop Evolution 44, 523-532.
Ellis, R.H., Hong, T.D., Martin, M.C., Pérez-García, F. and Gómez-Campo, C. (1993). The long-term storage of seeds of seventeen crucifers at very low moisture contents. Plant Varieties and Seeds 6, 75-81.
Vertucci, C.W. and Roos, E.E. (1990). Theoretical basis of protocols for seed storage. Plant Physiology 94, 1019-23.
Walters, C. and Engels, J. (1998). Effect of storing seeds under extremely dry conditions. Seed Science Research 8, 3-8.