Re: Any experience with GA3?

Betsey:

We have been using GA-3 for many years now. We also sell it in our
catalogue. ($7.50 Canadian for 100mg 95% concentration. Translated into
about $4.75 USA after exchange rate). It comes in a white powdered form
that is dissolved in water and applied to the seeds, either in the form
of a soak or by spraying on with a spray bottle.

It is important to note that GA-3 is only necessary for the germination
of very particular species, although it is also beneficial to others.
Few plants absolutely REQUIRE it. Examples of a few that do are: Cornus
canadensis (Bunchberry), the rosulate violas of the high Andes, Zizia
aptera (though not conclusive). 

After years of trying to figure out why we have been unable to germinate
viable seed of Salvia glutinosa from our own stock, using every method
possible,  we have this year discovered that it has a GA-3 requirement.
One would not have expected this from one species in this genus of
largely easy, warm germinators.

Our most satisfying time with it, however has been its use for the
choice Japanese woodlander, Glaucidium palmatum, which historically
needed to be sown absolutely fresh, or required many years of waiting
through alternating cold-warm treatments for germination. Using GA-3
germination can be expected, in a staggered pattern, at warm, starting
anywhere from 2 weeks on. 

It has long been used for speeding up the process of growing  Trillium
from seed. It can also be used to avoid the intervening cold period in
the usually hypogeal germination pattern of Lilium canadensis (the
Canada Lily is a hypogeal germinator- it normally germinates at warm,
but only forms its bulbil at this stage. A further 3 month cold period
is required, after which time the first true leaf will be sent up.)
Treating with GA-3 means that both of these events- bulb formation and
first leaf can happen at the initial warm period, saving a great deal of
time and effort. 

Some entire genera (Thalictrum, Viola, Aquilegia) have germination
dramatically stimulated by its use. However, this does not mean that
germination is impossible without it. In fact, it was with the genus
Thalictrum that our experiments originally began. Many Thalictrums
require cold conditioning and even then, germination rates are not
impressive. When using GA-3 and keeping the seeds at warm conditions,
germination of over 90% can be expected within a period of 2 weeks.
Viola and many of the choice, non-hybrid species of Aquilegia follow
approximately the same pattern after treated with GA-3.

It's use on seed such as Lobelia cardinalis (which will normally
germinate in about 5-6 weeks in light and warm conditions) is to
dramatically speed up the germination (to approximately 2 weeks in the
same environment). In other cases, its use will replace the need for
certain species to have light as an absolute requirement for germination
(the GA-3 means the seeds can be germinated in the dark, where they
normally need light).

Some species (Sanguinaria canadensis, our common Blood-root), require
different gibberelins (GA-7) to germinate. This is obviously naturally
present in the woodland soil, where they self sow here. 

In some cases, its use is detrimental, or even fatal to the seeds. So,
unless you are willing to risk losing your seed, do not use it
indiscriminately. I highly recommend  puchasing Norm Deno's Germination
Theory and Practice (139 Lenor Drive, State College PA 16801) $20.00
postpaid where details of its use and the suggested species are
outlined. 

Cheers.
-- 
Kristl Walek
Gardens North Seed
5984 Third Line Road, N.
North Gower, Ontario
Canada K0A 2T0

Phone: (613) 489-0065
Fax: (613) 489-1208

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