8
In Other Words
January 20
2022
Diggin’ in the Dirt: A Look at Seed Viability
By Chip Bubl
Oregon State University
Extension Service - Columbia County
The OSU Extension Office is fully
reopened. Mask still required inside.
The best way to reach me directly is
with the email below.
Events:
Master Gardener Training: We are
still unsure whether it is possible to hold
a live class this spring. It won’t start
in February but might get started mid-
March or later. It will be in St. Helens
if we have it. COVID is so challenging.
Call or email us for updates.
Grafting workshop: It will be held in
person at the OSU Extension office in St.
Helens on Saturday, February, 26. Cost
is $20 for five apple rootstocks and sci-
ons to graft onto them. Most people end
up with four and often five new apple
trees. Time will be from 9:00 am until
noon. Class limited to the first 15 people
due to safety issues with knives used in
grafting. Masks will be required.
Columbia County Small Woodlands
Association tree sale is back! On Sat-
urday, March 12, Columbia County
Small Woodlands Association will hold
its 23 rd annual tree sale. The sale begins
at 8:30 am at the Lawrence Oil (Pacific
Pride) parking lot in St. Helens on Hwy
30. The address is 845 N Columbia Riv-
er Hwy. 22 different species of decidu-
ous and conifer trees will be available
for purchase. Prices range from $1.50
to $6. We will also have bags of Doug-
las fir, noble fir, western red cedar, and
New Day Massage
and Bodyworks
#10732
For Auld Lang Syne
and a New Year of
Community Building
coast redwood available for purchase.
Cash and checks will be accepted for
payment. As always buyers are advised
to come early for best selection.
Seed dormancy and summer garden
weeds
Seeds of native plants and our
weed seeds (mostly non-native plants)
have evolved complex strategies to sur-
vive years in soil. Temperate zone seeds
that grow spring through fall are dor-
mant through at least their first winter.
That makes sense, since an acorn that
germinated in a warm, moist October
would be toast in cold December.
A plant hormone “sits” on the
seed dormancy “lock”. The hormone
concentration decreases as the seed es-
sentially measures winter temperatures.
When enough cold weather is tallied,
the hormone “lock” is released and the
seed is free to germinate. The seed then
responds to warm, moist soils to send
out its root and shoot and face the chal-
lenges of the above-ground world.
But here is where it gets even
more interesting. If a lambsquarters
plant sheds its 50,000 seeds in July, they
won’t all germinate the next summer.
Some are locked for one winter, but oth-
er seeds may have to measure 5, 15, or
even 30 winters before they can germi-
nate! That is hedging their genetic sur-
vival bet big time. And that is what evo-
lution is all about. For those plants, their
genes will survive even if some sum-
mers are lethal to their newly emerged
seedlings since still-dormant seeds will
germinate in the coming years.
This might make you think,
what about our vegetable seeds? Don’t
we want them to germinate all at once?
The answer is yes, we do want com-
plete germination. So, from the wild
plants they came from, we have (over
about 4,000 years or more) bred most
of the genetics of delayed germination
out of them. If we were to disappear
from the earth, the lettuces, beans,
peppers, cabbages, etc. that retained
some vestigial genes for surviving
winter would revert to their wild-type
forms quickly. The faster they did it,
the more competitive they would be-
come in a world without us.
There is a long running experi-
ment on weed seed longevity in Michi-
gan, started by Professor Beal. In 1879
(!), he mixed seeds of a number of
weed species in sand, placed the same
baceous perennial
plant. But there are
a lot of factors that
affect survival. A
lot of insects, small
mammals, and even
fungi will take the
seed numbers way
down. Seeds left
on the surface are
more
vulnerable
in comparison to
ones that are buried.
Grass seed survival
times are quite low
relative to broadleaf
weeds.
mixtures in a number of glass tubes, and
buried them. Each tube had multiple
seeds of each species. A tube has been
dug up, first at short intervals and now at
20 year intervals. When a tube was dug,
the seeds were tested for germination in
a greenhouse. At the current 142 years,
only one plant, a mallow, still germinat-
ed. But a number lived well into their
80s or more. For more information, see
https://www.nytimes.com/2021/04/21/
science/beal-seeds-experiment.html .
There are records of seeds that
have been buried for 800 or more years
and remained viable. But where they
were buried makes a huge difference.
Most were in far north latitude peat
bogs. Those seeds were almost continu-
ously waterlogged and the soil tempera-
tures were very low. Those combined
conditions slow respiration to a crawl (a
seed, even dormant, is still alive) which
maintained their viability. The Egyptian
pyramid stories (dry and warm) are not
very reliable.
The table below gives some
information about seed production per
plant per year and the potential survival
rates over time. All are summer annuals
except Canada thistle which is an her-
Weed species
Lambsquarters
Free newsletter (what a deal!)
The Oregon State University Extension
office in Columbia County publishes a
monthly newsletter on gardening and
farming topics (called Country Living)
written/edited by yours truly. All you
need to do is ask for it and it will be
mailed or emailed to you. Call 503-397-
3462 to be put on the list. Alternatively,
you can find it on the web at http://ex-
tension.oregonstate.edu/columbia/ and
click on newsletters.
Take excess produce to the food bank,
senior centers, or community meals
programs. Cash donations to buy
food are also greatly appreciated.
The Extension Service offers its pro-
grams and materials equally to all
people.
Contact information for Oregon State
University Extension Service –
Columbia County Office
505 N. Columbia River Highway
St. Helens, OR 97051
503-397-3462
Email:
chip.bubl@oregonstate.edu
Number
Seed
of seeds
survival
per plant
(years)
72,450
40
Purslane
52,300
40
Dandelion
15,000
6
Pennsylvania smartweed
19,300
30
Canada thistle (per stem)
680
21
117,400
10
7,160
3
25,000
3
Pigweed
Barnyardgrass
Crabgrass
Vernonia’s Voice
is published
on the 1 st and
3 rd Thursday.
Look for our
next issue on
February 3.
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