I'd like to follow up on something I heard regarding plant materials treated
with herbicides/pesticides needing to be set aside for a longer period of
time. Apparently, the heat generated through the composting process can
augment herbicide damage.

Can anyone suggest where to go to check this out?

"B. Midler" wrote:

I'd like to follow up on something I heard regarding plant materials treated
with herbicides/pesticides needing to be set aside for a longer period of
time. Apparently, the heat generated through the composting process can
augment herbicide damage.

Can anyone suggest where to go to check this out?

With a few notable exceptions, most herbicides are not very long lasting and
should break down thoroughly to realtively harmless components with a proper
composting process. Rather than adding to the problem, the heat and microbial
activity of a proper composting process is the best way to ensure you have a
'clean' finished compost. There are a couple of extremely persistant herbicides
that do not breakdown properly through the composting process (clopyralid
primarily, and another whose names escapes me), but these are used mostly in
agricultural situations and such a flap has been raised about them recently that
most commercial compost has been tested to make sure they are not present. They
tend to affect plants in only certain families, anyway (largely edible crops)
and any woody ornamentals are pretty much immune.

Just make sure your compost is properly "cooked" - that will adequately remove
any lingering effects of pesticides as well as neutralize most disease
pathogens.

pam - gardengal

On Fri, 07 Feb 2003 00:29:09 GMT, Pam wrote:

Just make sure your compost is properly "cooked" - that will adequately remove
any lingering effects of pesticides as well as neutralize most disease
pathogens.
And how many home composters take their compost piles through the
heat cycles sufficient to manage pesticides and herbicides?



Regards,

tomj

Tom Jaszewski wrote:

And how many home composters take their compost piles through the
heat cycles sufficient to manage pesticides and herbicides?

As I understand it, most of these chemicals break down pretty rapidly
in a normal outdoor environment. The heat of composting simply
accelerates the process.

Send email to jsachs177 at earthlink dot net.

"B. Midler" wrote:

I'd like to follow up on something I heard regarding plant materials treated
with herbicides/pesticides needing to be set aside for a longer period of
time. Apparently, the heat generated through the composting process can
augment herbicide damage.

Keep in mind that the dreaded PCBs that contaminated a lot of
soil are broken down by normal soil bacteria ... most of the site
where they piled up the contaminated spoil to incinerate were
clear of detectable PCBby the time they got around to
incinerating.

Soil bacteria are amazing ... they can eat almost anything.

Just compost as normal.

Tsu

--
To doubt everything or to believe everything
are two equally convenient solutions; both
dispense with the necessity of reflection.
- Jules Henri Poincaré

Picloram, a broadleaf weed control has shown to be persistent through all
stomachs of a cow, composted and used on nightshades still causes foliar
cupping. There are very persistent problems with herbicides in compost.
Picloram is one of the worst. You can do a search on your own to find out more.


On Thu, 06 Feb 2003 19:11:15 GMT, "B. Midler" wrote:

I'd like to follow up on something I heard regarding plant materials treated
with herbicides/pesticides needing to be set aside for a longer period of
time. Apparently, the heat generated through the composting process can
augment herbicide damage.

Can anyone suggest where to go to check this out?

On Fri, 07 Feb 2003 02:24:07 GMT, Tom Jaszewski
wrote:


And how many home composters take their compost piles through the
heat cycles sufficient to manage pesticides and herbicides?



Regards,

tomj


ME ME ME ME! But I inoculate my compost with organic compost I buy.

On Fri, 07 Feb 2003 06:01:00 GMT, Jonathan Sachs wrote:

Tom Jaszewski wrote:

And how many home composters take their compost piles through the
heat cycles sufficient to manage pesticides and herbicides?

As I understand it, most of these chemicals break down pretty rapidly
in a normal outdoor environment. The heat of composting simply
accelerates the process.

Send email to jsachs177 at earthlink dot net.

Not accurate. See my other post.

That's the chapter and verse we get from monsanto and dow...look into
some of the information on the inerts and their effect on soil
biology.



On Fri, 07 Feb 2003 06:01:00 GMT, Jonathan Sachs
wrote:

As I understand it, most of these chemicals break down pretty rapidly
in a normal outdoor environment.




Regards,

tomj

Thanks for the feedback. I was able to do the research, and it seems that
"properly cooked" doesn't quite do it for commercial or home composters.
Seems there's a set-aside time also required. It's that resting period I'm
trying to determine.
Clopyralid damage is seen in use from home composted materials, largely from
those who add material from lawns serviced by commercial firms. In addition,
I was quite surprised to see that Washington State Agriculture warned about
the use of straw and manure on sensitive crops (peas, beans and tomatoes) --
exactly where I was seeing cupping.
Can never rest when it comes to staying current on horticultural practices.
There's always something new. And things are always so simple.

"Pam" wrote in message
...
There are a couple of extremely persistant herbicides
that do not breakdown properly through the composting process (clopyralid
primarily, and another whose names escapes me), but these are used mostly
in
agricultural situations and such a flap has been raised about them
recently that
most commercial compost has been tested to make sure they are not present.
They
tend to affect plants in only certain families, anyway (largely edible
crops)
and any woody ornamentals are pretty much immune.

Just make sure your compost is properly "cooked" - that will adequately
remove
any lingering effects of pesticides as well as neutralize most disease
pathogens.

pam - gardengal

Why do you innoculate your compost with purchased compost? There are enough
microorganisms brought in on the roots of the plants you are composting.

" ME ME ME ME! But I inoculate my compost with organic compost I buy.

I hadn't heard of Picloram as being persistent in compost. But then again, I
hadn't heard of it at all. Can't find anything specific about composting
since it's a ranch product, but I'll keep looking.
Thanks for the heads up.


"animaux" wrote in message
...
Picloram, a broadleaf weed control has shown to be persistent through all
stomachs of a cow, composted and used on nightshades still causes foliar
cupping. There are very persistent problems with herbicides in compost.
Picloram is one of the worst. You can do a search on your own to find out
more.


On Thu, 06 Feb 2003 19:11:15 GMT, "B. Midler" wrote:

I'd like to follow up on something I heard regarding plant materials
treated
with herbicides/pesticides needing to be set aside for a longer period of
time. Apparently, the heat generated through the composting process can
augment herbicide damage.

Can anyone suggest where to go to check this out?

"Pam" wrote in message
...

Just make sure your compost is properly "cooked" - that will adequately
remove any lingering effects of pesticides

pam - gardengal

Some of the studies that show pesticide residues after hot composting to
be completely safe are not thinking organically, but are assuming safe
levels & degradation baselines that are tainted by the chemical
manufacturers' optimistic & propogandistic assertions about what
constitute safe levels. Deeper analyses disliked by the chemical companies
also show that even when a pesticide does degrade due to heat or passage
of time, new chemicals arise, some of which are themselves problems.

Plus, pesticides survive worm composts more or less intact. Had the pile
gotten hot enough for heat-tolerant microbes to break down pesticide
chemicals, the worms would be killed by the same process. Excellent
composts are made at lower temperatures by worms, but if pesticides go
into the process, pesticides come out of the process.

And that's without considering poor composting practices. I think most of
us from time to time jump the gun a bit & use some composts that could've
gone a while longer, or bury unfinished composts deep enough to finish off
right in the ground where new gardens are to be installed. These practices
are not generally harmful, but would more certainly mean the material
cycled back into the garden was never sufficiently hot to break down
unwanted chemicals.

There are a few pesticides & herbicides that survive even hot composts,
some banned (like chlordane) are insufficiently degraded even after many
years. Diazinon, atrazine, 2,4-D, & pendimethalin are among the
implicated. In big commercial or metropolitan composts they often use
microbial innoculants -- the same microbes used to help clean up oil
spills -- because normal composting would never rid the end-product of
pesticides where large amounts of contaminated grass clippings went into
the mix.

I wouldn't add anything to my composts I thought had been grown with
pesticides or herbicides, which pretty much rules out any grass clippings
from anywhere but my own yard.

-paghat

--
"Of what are you afraid, my child?" inquired the kindly teacher.
"Oh, sir! The flowers, they are wild," replied the timid creature.
-from Peter Newell's "Wild Flowers"
See the Garden of Paghat the Ratgirl: http://www.paghat.com/

paghat wrote:

"Pam" wrote in message
...

Just make sure your compost is properly "cooked" - that will adequately
remove any lingering effects of pesticides

pam - gardengal

Some of the studies that show pesticide residues after hot composting to
be completely safe are not thinking organically, but are assuming safe
levels & degradation baselines that are tainted by the chemical
manufacturers' optimistic & propogandistic assertions about what
constitute safe levels. Deeper analyses disliked by the chemical companies
also show that even when a pesticide does degrade due to heat or passage
of time, new chemicals arise, some of which are themselves problems.

Plus, pesticides survive worm composts more or less intact. Had the pile
gotten hot enough for heat-tolerant microbes to break down pesticide
chemicals, the worms would be killed by the same process. Excellent
composts are made at lower temperatures by worms, but if pesticides go
into the process, pesticides come out of the process.

And that's without considering poor composting practices. I think most of
us from time to time jump the gun a bit & use some composts that could've
gone a while longer, or bury unfinished composts deep enough to finish off
right in the ground where new gardens are to be installed. These practices
are not generally harmful, but would more certainly mean the material
cycled back into the garden was never sufficiently hot to break down
unwanted chemicals.

There are a few pesticides & herbicides that survive even hot composts,
some banned (like chlordane) are insufficiently degraded even after many
years. Diazinon, atrazine, 2,4-D, & pendimethalin are among the
implicated. In big commercial or metropolitan composts they often use
microbial innoculants -- the same microbes used to help clean up oil
spills -- because normal composting would never rid the end-product of
pesticides where large amounts of contaminated grass clippings went into
the mix.

I wouldn't add anything to my composts I thought had been grown with
pesticides or herbicides, which pretty much rules out any grass clippings
from anywhere but my own yard.

-paghat

With the exception of your last statement, we'll have to agree to disagree.
The microbial activity of a properly managed compost pile is sufficient to
degrade to insignificant levels most commonly available residential pesticides
(with the exception of the two herbicides previously mentioned). Both diazinon
and 2,4-D have extremely short half-lives in the soil (7 days or less) and do
not require even an active composting process to breakdown, provided leaching
is not an issue.

Worm compost is another issue - it is not a true composting process (no heat
generation), but rather a digestive function of the worms, resulting in their
excrement being very high in plant nutrients. It is not recommended they be
fed much in the way of yard trimmings, anyway.

I also agree that home compost is often not mananged through a proper
composting process that develops temperatures hot enough to cook out pathogens
and pesticide residue, nor is it allowed the proper period of cooling that
encourages the populations of low temp microorganisms that complete the
composting process. Given these conditions, the only way one can be assured of
having truly "organic" compost is by confirming exactly what goes into the
finished product, however, local commercial composts meets certified organic
standards, for whatever that may be worth.

pam - gardengal
Certified Maser Composter

It's just a starter for very green materials. Hey, it works for me.


On Tue, 11 Feb 2003 16:00:18 GMT, "B. Midler" wrote:

Why do you innoculate your compost with purchased compost? There are enough
microorganisms brought in on the roots of the plants you are composting.

" ME ME ME ME! But I inoculate my compost with organic compost I buy.