Viewing post #932101 by davidsevit

RickCorey said:>> 5.what is best to preserve zinnia seeds.....paper bags or sandwich nylon degradable bags

As long as the seeds stay DRY, either one can work.

Also, if you are only storing seeds for one year, or maybe two years, and you don;t mind if their viability (% germination) goes down from 90% to 50%, almost any kind of storage that's reasonably dry and cool and non-varying will work out OK.

However, suppose you want to keep some seeds with high viability for 3, 4, 5 or more years.

If the air where you store them varies in humidity, or is ever much above 40% RH, , paper will let the humidity changes go right through and affect the seeds. That's very bad. If you want to store seeds for more than 1-2 years, they need stability and cool dryness.

Swings in humidity or temperature shorten the storage lifetime of seeds.
So plastic might be better in that case (if the seeds are very dry when you seal them away).

However:thank you for a long and informative answer......by the way the compost heap is very soggy ...i am less worried because of the teribly hot weather .but i think i will start a new one and let this one rest

If you put seeds into plastic and seal it before the seeds are dry, Dry, DRY, more humidity will keep coming out of the seeds. Air inside the plastic Zip-Loc will become more humid than 50% RH. Rot will start soon after that.

OK, dry the seeds below 50% RH before sealing them in plastic or glass. That slows down their metabolism so LESS humidity is released over time.

But remember that humidity KEEPS coming out of seeds, because they are metabolizing slowly. And they metabolize faster if their humidity is (say) 40-50% instead of 15% to 20%.

So dry those seeds below 20% RH before sealing them tight!

Fortunately, plastic does let humidity leak slowly right THROUGH thin plastic film. And those cheap "zippers" on Zip-Loc bags are NOT any kind of hermetic seal.

So even if you seal up some seeds that are only 30-40% RH dry, the extra humidity will keep coming OUT of the baggie IF you keep the air around the baggie really dry - like 20% or 15% RH.

Now we're talking about a desiccant, or living in a desert with constantly-low-humidity.

The desiccant and seeds have to be sealed together in some tight jar, or else the desiccant will try to pull the humidity out of the air in your house, yard and county ... until it uses up its capacity for water and is exhausted.

If you seal seeds and some desiccant into a jar, it doesn't matter whether you packed the seeds in paper or plastic. The very-dry-air in the jar will slowly pull excess humidity out THROUGH a plastic Zip-Loc baggie.

It will rapidly JERK excess humidity out of a paper envelope full of seeds, so don't seal seeds with desiccant until they are finished ripening and drying slowly on the vine.

http://garden.org/ideas/view/R...

http://garden.org/ideas/view/R...

I was trying to write an article about desiccants in general, but didn't have enough good photos, and then I left it unfinished as a blog entry

http://garden.org/blogs/view/R...

The short form is: get silica gel from a craft store that sells flower-drying supplies. Make small paper packets with a tablespoon of silica gel. For example, use a paper coin envelope.

Kew Royal Botanic Gardens Technical Information Sheets
http://www.kew.org/sites/defau...
"Seed life span approximately doubles for every 10% reduction in seed eRH."

Many other Kew Tech Info Sheets about seed collection and storage:
http://www.kew.org/science-con...