Scottish Rock Garden Club Forum
General Subjects => General Forum => Topic started by: Lesley Cox on November 28, 2012, 10:27:10 PM
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I seem to be getting seedlists by email almost daily at present, some forwarded by Forumists and others from out of the ether somewhere. All are of great interest even though this time round I am avoiding ordering anything as I have many yet to sow and a major move rapidly approaching so that I don't want to add yet more work to what has still to be done.
However, I'm starting this thread not for advice, but in hope of starting a discussion, on the subject of seed age.
One list I received this morning has hundreds of items but though I didn't count, it seemed to me that well over half were not this year's seed, but collected from the wild - and some from garden sources - over a period of as much as 7 years. The oldest items I noted were from 2005 collections. In my favourite genus Iris, 2 were from 2011 and others as old as 2006, none of this year's collecting.
At least the proprietor of this extensive list is honest enough to say the age of each listing and I wonder, when a list arrives with no dates included, are all those items from the current year or are some from up to several years ago?
One has to assume that the person listing and hoping to sell the seed has proper storage facilities and makes good use of them, but I wonder what are the chances of germinating primulas, say, from seed which is so old? Is it general practice to list items this year left over from previous years and when is seed considered too old to list? I throw out numerous pots of ungerminated seed of some genera after a couple of years while I keep others much longer but I'd hesitate to list for sale, seed which I'd had in my possession for as much as 6 or 7 years, even at much reduced prices.
I'd like to hear what others think about this.
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Usually old seeds from the B.C. alpine club or primrose society are offered
free, and I have been surprised at how readily some old seeds will
sprout. However, I wouldn't want to pay for old seeds unless I know for
sure that they are a kind that keeps well.
I found pea family seeds from Australia germinated quickly even though old - the kind
of seed that one pours boiling water on. Their hard shells seem to have protected them
well.
It can depend on the species, not just the genus.
Primula sieboldii needs to be fresh, but I had no problem with
twenty year old polyanthus seed that had been kept refrigerated.
I have a hard time with many kinds of iris seed, even when the seed is
new. (or, I think it is new.)
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Diane,
Is it just peas you pour boiling water on? I've often wondered about such a procedure but never done it.
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Chris,
I did it only once, with seeds I bought in Australia and didn't get around
to sowing for several years.
I wrote about it on the forum last year. I will copy a bit here:
pea family - Kennedia, Gompholobium, Bossiaea, Hovea, etc.
I usually abrade or nip the hard seedcases of the pea family, but the
back of the packet said to pour boiling water on the seeds and allow it
to cool overnight before sowing. I did that for most of the seeds but also
did my usual routine for a few from each package. Well, the packet
instructions were the best - Indigofera australis germinated almost
immediately. The rest are slower, but I am sure they will also do well.
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Thanks. I think I'll give this a try. I have some seed of purple podded peas that I keep meaning to sow again but they remain in the packet. Next spring I'll give them a go with this treatment....
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Chris,
I think this might be overkill for actual peas (Pisum). Just a soak in
room temperature water has always started them sprouting for me.
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Yeah.... but these have been laying dormant for about 7 years.... may take a shock to wake them up don't you think?
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If they still look reasonably plump or at least not totally shrivelled, and if not chewed by anything, they should be OK after a good soak in water starting as hot but not boiling and let cool overnight. If there are enough, try a few each way and report the results. (For the other procrastinators among us who may have similar packets. ;D)
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This past week I heard a broadcast on NPR that was about a guy that initiated a study about 70 years ago. He buried a number of bottles of weed seeds. Every 10 years he opened a bottle and tested germination. When he got too old to continue the study he passed it on to someone else who also passed it to another. The study has now opened a bottle of seed that was 70 years old and some seeds were still viable. There are enough remaining bottles to test until they are 110-120 years old. Sorry I don't have names or more specific information.
You know what they say about a weed. A weed is only a plant growing in the wrong location. Well.... not in my book!
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I agree Leon. A weed is a weed is a weed.
I'd bet these gentlemen were fond of a little dram or two of Scotch whisky as well as their seeds. That would age even better than the weed seeds and be more rewarding in the sampling I should think. ;D
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That seed experiment was by Dr Beal in Michigan in 1879.
After 120 years, in 2000, there was 50% germination of
Verbascum blattaria and a much lower rate of Malva rotundifolia.
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Thank you Diane for clearing some of my mis-information up. I was hoping I was recalling some of the info correctly. I was traveling at the time I heard it and couldn't take notes. I did hear there were two species that were still viable.
Lesley, I think if the Scotch had been left too it would have not last 120 years. It would have been consumed long before it got much age to it.
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I use hot or boiled water on Lupines and hard coated tropical seeds like Vigna caracalla. It gives a much better germination.
Sometimes I remove a small part of the seed coat before pouring the water over the seeds.
About the longevity of seeds: There is no 'rule' to say which seed stays viable for a long time. I started making a list. Every time I see a scientific article about the longevity of certain seeds, I make a note of it. And also my own experience with older seeds is noted on the list.
In general seeds of real annuals will stay viable for 3 years, although there are some exceptions.
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Once whisky is in the bottle keeping it serves no useful purpose. It's not like wine, so does not improve with age.
I can see why Australian seeds respond to heat treatment. They have evolved in a bush fire environment, so germinating after fire, when the area is clear of vegetation and is rich in nutrients is a useful trick. I have received acacia seeds with "wrap seeds loosely in news paper and set on fire" as part of the instructions.
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Once whisky is in the bottle keeping it serves no useful purpose. It's not like wine, so does not improve with age.
Not entirely true, Anthony - keeping some handy for emergency rations oops, I mean emergency medication - serves a very useful purpose ::) ;D
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Once whisky is in the bottle keeping it serves no useful purpose. It's not like wine, so does not improve with age.
I can see why Australian seeds respond to heat treatment. They have evolved in a bush fire environment, so germinating after fire, when the area is clear of vegetation and is rich in nutrients is a useful trick. I have received acacia seeds with "wrap seeds loosely in news paper and set on fire" as part of the instructions.
I visited a commercial Erica nursery in South Africa once and their standard procedure was to sow Cape Erica seed onto the surface of damp substrate then pass a blowtorch over the tray. The exact speed of the pass and setting for the torch was something the owner had developed a feel for after years of trial and error. The Bainbridges technique (published in The Rock Garden) of using a domestic oven for a short time would be rather safer and more scientific, if not as much fun ;) ;D
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By the way Lesley, I do agree with you about the listing of old seed.
If the person listing it knows what they are doing, and sticks to only keeping those species which are known for long viability then fair enough.
It was interesting to me when I obtained some of the old seed from Jenny Archibald's final clearance after Jim passed away. It did come with the clear caveat that viability was unknown. Of 15 species of Fritillaria only one showed any sign of germination. The 12 Allium species were a total loss.
I have not been able to find much information at all on longevity of Allium seed but my experiences from seed exchanges and from purchases from some sources suggest that the seed is surprisingly short lived?
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pass a blowtorch over the tray
I assume a plastic pot/tray is not recommended? ::)
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I assume a plastic pot/tray is not recommended? ::)
By all means try it if you like Peter.. ;D
I think they were using metal trays.
Before my recent greenhouse overhall I had terrible problems for years with tiny annual grasses seeding everywhere (They were the unintended legacy of an experiment for my degree course). For control each year I would do the usual early september bulb watering then after a week or so when the grasses germinated I'd use a hot air paint stripper over the top of the pots to burn them off before the bulb noses appeared. This brief treatment was tolerated by the plastic pots but I did melt a few labels....
This year Susan and I repotted EVERYTHING in the greenhouse, replaced the plunge sand and capillary matting and cleaned all the pots inside and out. So far this autumn - no grass :)
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Allium seed is germinating the best if it's not older than 1 year, but I grew some Allium seeds with that were 2 years old.
I planted them in the same container as the fresh seeds. The older seeds germinated later and more irregular and the germination percentage was lower, but still very acceptable.
There are some reports that older Allium seeds need a warm-cold-warm period to break their dormancy
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I am fascinated by that idea of using a blowtorch for Erica seed. I wonder if any material was placed on top of the seed to burn because I thought the received wisdom now was that chemicals in smoke were important to stimulate germination.
I have a bottle of 'Liquid Hickory Smoke' which I thought I might try with seed from fire prone habitats - and if it doesn't work it 'imparts a wonderful smoky flavour to your favourite foods'!
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The little blowtorch I was given as an aid to making the perfect creme caramel and like desserts, might be a good one to try. The flame is very small and concentrated, contolled by distance from the thing to be torched.
At my market, there are manuka smoked eggs. Ordinary eggs which are smoked over manuka shavings and the shells come out blackened but the egg istelf is unchanged so can be scrambled or whatever. The guy who sells them sells many many dozens to upmarket restaurants throughout the country and is even exporting to Australia and S E Asia now. Gordon Ramsey uses them - not that that's a recommendation. ::) Bacon and smoked eggs a real treat. :D
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I am fascinated by that idea of using a blowtorch for Erica seed. I wonder if any material was placed on top of the seed to burn because I thought the received wisdom now was that chemicals in smoke were important to stimulate germination.
I have a bottle of 'Liquid Hickory Smoke' which I thought I might try with seed from fire prone habitats - and if it doesn't work it 'imparts a wonderful smoky flavour to your favourite foods'!
No material on top of the seed Tim - reliance was on cracking the seed coat being enough. But - I can't guarantee a subsequent watering did not use 'smoke water'.
The research on smoke chemical effects is pretty extensive and convincing and the relevant chemical (a butenolide) will stimulate germination in synthetic form without any actual smoke being involved.
I've used the Kirstenbosch 'liquid smoke' for Cape Ericas with some success, percentage germination is reasonable but not exactly spectacular so I think perhaps the seed coat cracking is at least as important.
Incidentally - with some of the Restio species I tried the smoke water was essential - absolutely no germination without it and plenty with. Sadly I can no longer afford the space for Fynbos plants like these, the bulbs have edged almost everything else out!
Lesley - I think your little blowtorch would be well worth trying!
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Allium seed is germinating the best if it's not older than 1 year, but I grew some Allium seeds with that were 2 years old.
I planted them in the same container as the fresh seeds. The older seeds germinated later and more irregular and the germination percentage was lower, but still very acceptable.
There are some reports that older Allium seeds need a warm-cold-warm period to break their dormancy
Thank you Jonna - that is interesting and helpful :)
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No material on top of the seed Tim - reliance was on cracking the seed coat being enough. But - I can't guarantee a subsequent watering did not use 'smoke water'.
Sorry, I could not help myself:
Deep Purple - Smoke On The Water 1975 (http://www.youtube.com/watch?v=3Zz1gOIxHPE#)
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It's OK Maggi, some things are just too tempting to resist ;)