On 19/05/2012 08:55, Michael Bell wrote:
It is widely stated that Sequoia seeds have poor germination. Or does
that mean that we haven't found the trigger for germination?

Last Wednesday I was shown round The Moorbank Botanic Gardens of the
University of Newcastle by Prof. Richards(Retd).

He showed us a Sequoia wellingtonia about 6ft high and told us its
story. As a final-year project, Emma Morebank, a student had studied
whether "smoked water" promoted the germination of Sequoia and found
that it did. She died died tragically young in 2007, and this tree,
one of the ones she had grown, was planted in her memory.

Searching Google for "smoke", "Sequoia", and "Germination" I find
anecdotal reports suggesting that smoke from the fires which are so
important in California promotes germination of Sequoia and this must
have been what Morebank was investigating.

It makes some kind of sense. For temperature alone to be the trigger,
there could only be few degrees between the temperature that would
trigger and the temperature that would kill. The chemical products of
burning in solution in water would be a much better trigger

If so, this is something we could use. We could char or burn wood
shavings, sawdust or cut and dried grass in an oven (preferably
electric, gas-heated ovens are ventilated) and pop in the seeds when
it has cooled down.

Or.

"Liquid smoke" is available, it seems to be mainly aimed at giving
that "Smokey tang" to cooked meats, but it is suggested that it might
help germination of Sequoia seeds.

Does anybody have any knowledge of these?


I believe that smoke treatment was first used in South Africa for restio
seeds. Restios had proved very recalcitrant to germinate under most
other successful regimens. The idea was then taken further with
Proteaceae (also difficult to germinate) and then picked up and
developed by Australian botanic gardens (notably Kings Park in Perth)
for their Proteaceae - and other families - seeds.

I have use it in the UK for Australian seeds, but developed my own
method. Pots of seed are placed in a propagator, with space for the
smoke generator. I use dried leaves of Australian plants I already grow
(Eucalyptus mainly, but also some Banksia, Dryandra, and Hakea). As the
leaves don't keep burning for long, I have tried using them soaked in
potassium nitrate (sometimes with the addition of tissue paper given the
same treatment) which usually keeps them glowing a bit longer. I put
them in a fireproof container on top of a metal grid, which is about 5
cm off the bottom. An old terracotta pot or a tin with a hole in the
bottom will do as the container; that allows air to circulate. A tea
light underneath gets the leaves going (you can try a gas lighter, but
the leaves soon go out). Put a fine metal grid over the top so flames
can't get through (I forgot to do this once and melted a seed propagator
lid!). After the smoke has dispersed, spray the pots to get the smoky
water into contact with the seeds. You can repeat the treatment once or
twice if you think it might help.

Two points to be aware off. Firstly, don't burn your greenhouse down!
You don't need that much smoke in such a confined space. Secondly, it
might not make any difference to the germination; some seeds have their
germination inhibited by smoke.

--

Jeff