RE: [compost_tea] Re: More information on storing worm castings/vermicompost

From: Kelly Slocum <kelly_at_bonterra.net>
Date: Thu, 1 Jan 2004 19:22:19 -0800

Kirk! I was hoping you'd be here. Thank you for the very kind welcome!
 
Hi_Yield, I'm not clear on your goal in using or wishing to encourage
worms, so please let me know if my response misses the mark.
 
The majority of worm species commonly used in vermicomposting or
castings production systems are not worms that over-winter as adults in
climates like that of Alaska as they are not burrowing species that can
escape the cold extremes. Because they tend to be surface dwelling
species (in nature), referred to as epigeic worms, the adults are killed
by the freezing temps. The amazingly hardy cocoons, however, survive
even Alaskan cold to hatch a new generation of worms when spring thaws
arrive. As such, many epigeic worms will survive in your garden
provided the soil environment is suitable to them, just not necessarily
as adults.
 
Eisenai fetida, commonly called the redworm, is the species most
commonly used in North American worm beds designed for waste management
or castings production, and is common to many areas of Alaska. Of all
the worm species identified for use in vermicomposting systems this
species has been identified as the one most tolerant of environmental
fluctuation, handling and variation in feedstock. It is a prolific
breeder and is found on nearly every land mass of the planet, thus there
are rarely concerns about introducing an alien species that might cause
local environmental concerns.
 
It sounds as though you are trying to increase worm populations in your
garden soil, however. If this is the case then the typical
recommendation is to not introduce any worms at all, but to amend the
soil so that localized worm populations will be drawn to the garden;
sort of the "if you build it, they will come" idea. It's important that
you keep in mind that the type and number of worms currently living in
your soil are the type and number that can be supported by your soil in
its current state. Worm populations will naturally achieve a status quo
based on available food, space and environmental conditions. Adding
more worms is often simply a death sentence for them because were the
environment suitable for more worms more worms would be present. If you
want more worms, you must correspondingly increase food resources, and
that means organic matter and its corresponding load of microbiology.
Earthworms derive the bulk of their nutrients not from organic matter or
soil particles, but from the bodies of the microorganisms living on that
organic matter and soil. As such, worms cannot survive in biologically
barren soils, and microbiology suffers in exposed soils with too little
organic matter, and in chemically contaminated soils. Mulch the soil,
increase the biology using good tea, plant roots and organic matter
additions, and the worms will ultimately come to work synergistically
within this food web.
 
Another challenge to trying to add worms to your soil is the need to
understand which worms will do well in your area, which is what I
believe you were asking specifically. So, to answer succinctly, I don't
know, though I wish I had such data! Determining suitable species is
not as simple as determining the local temperature range. Different
soil series, moisture levels, plant types, even barometric pressure
patterns in a given area will influence the worm species that can and
will survive. Few areas of the world have surveyed their local worm
species/populations, thus it is unlikely the data on which worms are
best for your soil have been collected. Your local agricultural
university or department of the environment would likely be those who
would have such information had it actually been collected. If you find
that they do, I would genuinely appreciate it if you would be willing to
share it with me!
 
Kelly
 
Kelly Slocum
Chief Science Officer, Vice President
Bon Terra, Inc.
phone 360.253.5465
fax 360.253.5466
email kelly_at_bonterra.net
htttp://www.bonterra.net
 
-----Original Message-----
From: hi_yield1 [mailto:hi_yield1_at_yahoo.com]
Sent: Thursday, January 01, 2004 3:50 PM
To: compost_tea_at_yahoogroups.com
Subject: [compost_tea] Re: More information on storing worm
castings/vermicompost
 
Dear Kelly
What kind of worm would you recommend for the far north, Alaska. I
would like for them to be able to overwinter in the garden and I have
some that do. But if I was to bring some in what species would you
advise? Thanks Hi_Yield1.

--- In compost_tea_at_yahoogroups.com, "Kelly Slocum" <kelly_at_b...> wrote:
>
> I realized after my post regarding worm castings storage (and the
emails
> that post generated) that we may not have adequately addressed the
issue
> of moisture content as it relates to storage. Plastic containers
are
> often viewed as advantageous for castings storage because they do
not
> breathe and will help to hold moisture in the material. When
castings
> have a moisture content no greater than that of potting soil from a
> freshly opened bag (approximately 15%-30% moisture) the plastic
helps to
> maintain that moisture level, preventing rapid drying and, thus, the
> potential damage to the biology. This relatively low moisture level
> also ensures that oxygen flow/diffusion through the materials is
> sufficient to maintain aerobicity. If the castings are too wet,
> however, air flow, and more importantly oxygen diffusion through and
> into the castings "pellets" can be decreased, a condition further
> exacerbated in plastic containers by the fact that plastic does not
> allow for fresh air movement into the container as well as do more
> porous materials like wood. So, in our discussions of how best to
store
> castings we need to include the topic of moisture level.
>
> When castings first come out of a worm system they tend to be rather
> wet. It is best to dry them before storing by spreading in thin
layers
> in a protected environment like a barn or garage floor. This
should be
> done out of direct sunlight as UV light can damage the beneficial
biota,
> and fans are not recommended as they can cause rapid drying of the
> surface material. If there is insufficient room to spread the
castings
> they can be piled, but the pile should be periodically turned to
prevent
> over-drying of the surface materials while the center of the pile
> remains wet and can potentially become anaerobic. Frequent turning
is
> not necessarily recommended, however, as another advantage to this
> drying phase is that it is also allowing the fungal biomass in the
> material to increase (in castings that had sufficient fungal
content and
> fungal foods to begin with). Frequent turning can inhibit this
process.
>
> While we do not want castings to be stored in an overly wet
condition,
> nor do we want them to dry completely. While 15% moisture will
actually
> feel very dry (castings will flow very much like dry sand at this
> moisture level) there is still a fair amount of water associated
with
> the stuff. Castings that are completely dry will feel gritty and
sharp,
> like sand, and become hydrophobic, meaning they will not be
re-wetted.
> You can leave completely dried out castings in a bucket of water
for a
> month and they will not adequately recover their ability to hold
water.
> So dry them down, but don't dry them out!
>
> I hope this provides a more comprehensive explanation for storing
> castings and helps to provide a base of information that helps folks
> make a better informed decision on castings storage concepts. I
> apologize if my previous post caused confusion!
>
> Kelly
>
> Kelly Slocum
> Chief Science Officer, Vice President
> Bon Terra, Inc.
> phone 360.253.5465
> fax 360.253.5466
> email kelly_at_b...


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Received on Thu Jan 01 2004 - 22:51:02 EST

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