Re: More on seaweed

Carol Moholt wrote:
> 
> I've heard over the years that seaweed and kelp have many properties of
> which we know only little. One story I hear is that it helps plants protect
> themselves from extremes of heat and cold.  Last winter a friend was
> starting some seedlings here in the SF Bay Area. She fertilized one flat
> with a commercial seaweed fertilizer, got interrupted, and forgot to
> fertilize the second. We had a really big freeze a few days later and the
> unfertilized seedlings died but the fertilized one didn't. Anybody else
> have any similar stories?

Hi Carol 
I looked up my index of miscellaneous facts and found this odd note
culled I think from the pages of Organic Gardening. 

First-aid frost protection.
Spray plants with  a solution of two tablespoons seaweed extract in a
gallon of water  - leaves, branches bark, buds, flowers, the lot. It
will give about 5 degrees (farhenheit presumably) of frost protection.

Seems to confirm your story pretty neatly.

> Second, I was doing some research for a book project and came across
> reference to an ingredient found in seaweed called mannitol, a compound
> that enhances absorption of nutrients already in the soil, as well as
> various hormones that stimulate plant growth. Comments?

Mannitol is, of course a type of sugar. i hadn't heard of this usful
property.
The hormone I have seen quoted as present in seaweed preparations is
giberellic acid, but it would seem there are probably  others.

One thing appears certain is that the seaweed preparations have far more
beneficial effects than comparable inorganic solutions of the same
salts, due to these extra organic compounds which are also present.
> 
> Finally, there's been some local experimentation in our area applying
> liquid seaweed fertilizers via foliage to control peach leaf curl. It does
> seem to work, but has to be applied just as the new leaves are coming out
> and reapplied frequently until they all emerge. Seems like a great idea if
> one forgets to do dormant spraying in January or just can't find enough
> rain free days to apply dormant oil. 

This sounds quite likely to work well to me in view of parallel
experiments using compost tea on some fungus diseases. The mechanism
seems to he a mixture of strengthening the leaf cells against attack
plus the material preventing the disease spores getting a foothold on
the leaf surface.

I am puzzled however by your remedies of dormant oil and lime sulphur,
as the only treatment recommended here against this particular disease
is COPPER spray at bud-burst. The oil cannot reach the fungus as far as
I know as it is overwintering in the closed buds and as I understand it
this is on fungus which is sensitive to copper, but not to sulphur.

Moira

-- 
Tony & Moira Ryan <theryans@xtra.co.nz>
Wainuiomata, 
New Zealand (astride the "Ring of Fire" in the SW Pacific).
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