Views: 260, Replies: 10 » Jump to the end
Drying Seeds with Silica Gel

By RickCorey
November 21, 2015

It can be slow to dry seeds thoroughly in humid weather and prevent mold. Seal partly dried seeds in a tightly sealed jar with a desiccant like silica gel to get them down to 15% eRH, which will give them the longest possible viable lifetime in storage.

[View the item] Give a thumbs up

Name: David Laderoute
Zone 5B/6 - NW MO (Zone 5b)
Ignoring Zones altogether
Seed Starter Avid Green Pages Reviewer Garden Ideas: Level 1
Image
DavidLMO
Nov 20, 2015 8:45 PM CST
And don't get seeds too dry. One of the early times I tried to use silica gel, I ended up with thousands and thousands of useless seeds. Highly recommend that you get some method check the level.
Seeking Feng Shui with my plants since 1976
Name: Rick Corey
Everett WA 98204 (Zone 8a)
Sunset Zone 5. Koppen Csb. Eco 2f
I helped beta test the first seed swap Plant and/or Seed Trader Seed Starter Region: Pacific Northwest Photo Contest Winner: 2014 Vegetable Grower
Avid Green Pages Reviewer Garden Ideas: Master Level Garden Sages I was one of the first 300 contributors to the plant database! I helped plan and beta test the plant database. Charter ATP Member
Image
RickCorey
Nov 20, 2015 8:59 PM CST
True, if the jar seals very well and you use more than a tablespoon or two of silica gel, don't check the humidity and leave them there for more than a week or two, you could go below 10% and that isn't good for seeds.

Thanks for bringing that up!

None of my large tubs seal that well. My problem is replacing small desiccant pkts often enough to keep them dry.

I also worry about drying "green" seeds too fast. If the seed is not entirely ripe before drying it below 30% eRH, I assume that would be a problem. Maybe letting it dry slowly also let's unripe seeds "go to sleep" before the dryness stops the ripening.

My perspective is mostly on what to do with literally soggy seed heads. Press them between paper towels surrounded by cotton towels, then ... hope they dry below 50% eRH before they turn visibly moldy. I've given up on soggy seed heads, because even after drying, I don't want to carry mold spores into my seed jars.

Seeds that must be used "fresh" may not tolerate drying at all. But they are relatively rare seeds.


Name: David Laderoute
Zone 5B/6 - NW MO (Zone 5b)
Ignoring Zones altogether
Seed Starter Avid Green Pages Reviewer Garden Ideas: Level 1
Image
DavidLMO
Nov 20, 2015 10:57 PM CST
"Green" seeds are and can be problematical. My own experience has not been good generally. Best to let nature mature them. If you pick "too" green you are usually not successful in my experience. Here the problem is not moisture per se, but maturity or ripeness. There can be exceptions. In cases I have succeeded, it was was placing the seeds on paper towel and in indirect light. Never place in a plastic bag in direct sunlight. That WILL fail.

You say "My perspective is mostly on what to do with literally soggy seed heads". A question. Why not let nature dry them on the plant? Am I missing something?

I do concur with the general comments of the original post.

Seeds that typically must be used fresh are usually tropical. And yes, if you dry them, they will be useless.
Seeking Feng Shui with my plants since 1976
Name: Rick R.
near Minneapolis, MN zone 4a
I was one of the first 300 contributors to the plant database! Garden Sages The WITWIT Badge Garden Photography Region: Minnesota Plant Identifier
Image
Leftwood
Nov 21, 2015 8:59 AM CST
DavidLMO said:Seeds that typically must be used fresh are usually tropical. And yes, if you dry them, they will be useless.


Temperate (not tropical) plants that are ephemeral tend to require fresh planting, also.

Name: Rick Corey
Everett WA 98204 (Zone 8a)
Sunset Zone 5. Koppen Csb. Eco 2f
I helped beta test the first seed swap Plant and/or Seed Trader Seed Starter Region: Pacific Northwest Photo Contest Winner: 2014 Vegetable Grower
Avid Green Pages Reviewer Garden Ideas: Master Level Garden Sages I was one of the first 300 contributors to the plant database! I helped plan and beta test the plant database. Charter ATP Member
Image
RickCorey
Nov 23, 2015 12:11 AM CST
DavidLMO said:"Green" seeds are and can be problematical. My own experience has not been good generally. Best to let nature mature them. If you pick "too" green you are usually not successful in my experience. Here the problem is not moisture per se, but maturity or ripeness. ...


I agree, and should have stressed "if you HAVE to pick seeds before they are fully ripe ..."

I also believe, but can't support, the idea that even ripe seeds "benefit from" fairly gradual drying, and that letting them do as much ripening and drying "on the vine" as possible probably maximizes their eventual viability.

DavidLMO said:...
You say "My perspective is mostly on what to do with literally soggy seed heads". A question. Why not let nature dry them on the plant? Am I missing something?
...


The first year I tried to save flower seeds, they weren't fully ripe when we got a few days of rain - and a few more - and a few more. That was when I learned there is no such strategy as "wait for a few dry sunny days in a row", past some particular date in early fall.

Now I know that if the seeds won't be ripe and falling by August or so, the weather might only give me a choice between unripe and soggy. I agree that "unripe" seldom becomes viable.

Maybe I can dry out ripe-but-soggy flowerheads and keep them from getting so moldy that you can see the mold. But since I still wouldn't let those seeds into my "stash" jars, I don't bother trying to save seeds that have been too wet too long.

My grandiose plan is to set up tall hoops and cover a bed with plastic to keep rain off something I was trying to breed or preserve - well, maybe after I retire.

Name: Rick R.
near Minneapolis, MN zone 4a
I was one of the first 300 contributors to the plant database! Garden Sages The WITWIT Badge Garden Photography Region: Minnesota Plant Identifier
Image
Leftwood
Nov 23, 2015 2:33 PM CST
Unripe seeds will never be soggy. They will just be wet!

Not that all ripe seeds can even become soggy, but if they are soggy from the weather, then they are either dead or ripe.
Name: Rick Corey
Everett WA 98204 (Zone 8a)
Sunset Zone 5. Koppen Csb. Eco 2f
I helped beta test the first seed swap Plant and/or Seed Trader Seed Starter Region: Pacific Northwest Photo Contest Winner: 2014 Vegetable Grower
Avid Green Pages Reviewer Garden Ideas: Master Level Garden Sages I was one of the first 300 contributors to the plant database! I helped plan and beta test the plant database. Charter ATP Member
Image
RickCorey
Nov 23, 2015 4:06 PM CST
I guess that's true.

Flower heads and some seed pods can absorb or hold water with either ripe OR unripe seeds.

And seeds will dry faster if removed from the head or pod containing them.

But if you have the luxury of not worrying about mold, it can be easier to clean seeds after letting them dry very thoroughly in their seed heads or in the pods. Trying to get viable, non-moldy seeds is easier if you don't have to play games like wringing water out of a flower-head and then pressing it between towels prior to "drying".
Name: David Laderoute
Zone 5B/6 - NW MO (Zone 5b)
Ignoring Zones altogether
Seed Starter Avid Green Pages Reviewer Garden Ideas: Level 1
Image
DavidLMO
Nov 23, 2015 8:10 PM CST
Leftwood said:Unripe seeds will never be soggy. They will just be wet!

Not that all ripe seeds can even become soggy, but if they are soggy from the weather, then they are either dead or ripe.


Not sure I fully understand, but I have dealt with seeds that appeared to be completely ripe - they were falling off the seed heads on their own. I was wanting to gather a few thousand. It then started raining and rained at least some every day for over a week. I gathered them in the rain and laid them out on bath towels which I changed often. Those suckers were beyond soggy - they were totally water logged. Big Grin

While I did finally get some to dry, the germination was horrible. < 5 % and should normally have been 90 % or better.

Seeking Feng Shui with my plants since 1976
Name: Rick Corey
Everett WA 98204 (Zone 8a)
Sunset Zone 5. Koppen Csb. Eco 2f
I helped beta test the first seed swap Plant and/or Seed Trader Seed Starter Region: Pacific Northwest Photo Contest Winner: 2014 Vegetable Grower
Avid Green Pages Reviewer Garden Ideas: Master Level Garden Sages I was one of the first 300 contributors to the plant database! I helped plan and beta test the plant database. Charter ATP Member
Image
RickCorey
Nov 23, 2015 8:32 PM CST
>> It then started raining and rained at least some every day for over a week.

it might be that several days in a row is too long. And yet, most seed pods must be able to survive SOME rain, or they would never come back after a rainy fall.

Or it may be Nature's usual "numbers game".

Produce 100,000 seeds.
90% rot before dropping.
Still have 10,000 seeds.
90% of those rot on the ground or are eaten.
Still have 1,000 seeds.
90% don't germinate
Still have 100 seedlings.
90% are eaten by bugs, rabbits & deer.
Still have 10 adult plants.

Oh my Gosh! A 99.99% death rate would still result in a plant population explosion.



Name: Rick R.
near Minneapolis, MN zone 4a
I was one of the first 300 contributors to the plant database! Garden Sages The WITWIT Badge Garden Photography Region: Minnesota Plant Identifier
Image
Leftwood
Nov 23, 2015 11:32 PM CST
Yes, depending on the type of seed, many scenarios could be manifesting:
--- Rick's suggestion above, where seeds rotted.
--- seeds might begin germinating, but then die due to inadequate constant moisture.
--- many species naturally have low viability rates, for instance many members of the Aster family (Asteracae/Compositae) - not just Aster species. In such a case, the soggy seeds would already be dead.
--- many species require pollination from a plant of the same species but different genetics. In other words, they can't pollinate themselves (or clones of the same plant cannot pollinate each other). Here, all "seeds" would be dead (actually never developed).
--- flowers may never have been pollinated properly from the start, due to inclement weather or lack of the right pollinating fauna. Here again, empty seeds often develop.
--- many sterile plants still produce what looks like viable seed.

I'm sure there are many more possibilities. It must happen occasionally, when pods (or whatever) do rot as you surmise, but we always need to be looking at all the probabilities.
Name: David Laderoute
Zone 5B/6 - NW MO (Zone 5b)
Ignoring Zones altogether
Seed Starter Avid Green Pages Reviewer Garden Ideas: Level 1
Image
DavidLMO
Nov 24, 2015 12:06 AM CST
A typical orchid makes 1 to 10 million seeds. The seeds have no food source like most seeds.
Seeking Feng Shui with my plants since 1976

« Garden.org Homepage
« Back to the top
« Forums List
« Drying Seeds with Silica Gel
You must first create a username and login before you can reply to this thread.

Today's site banner is by Paul2032 and is called "French Marigold"