On Wed, 05 Mar 2003 01:29:05 GMT, animaux
wrote:

On Wed, 05 Mar 2003 00:32:09 GMT, (Terry Horton) wrote:

This was a striking revelation when I first heard it at an Aggie soil
science lecture a few years ago. Homes of in our area which have been
fertilized even intermittently over the years were showing phosphorus
at levels high enough to last for generations! Yet lawn centers
continue to push "balanced" fertilizers, and then later Ironite to
overwhelm the iron deficiency caused by the P they sold you in the
first place (Ironite in any case being a problem worse than any
symptom it might mask). Even organic gardeners need to consider this
as most organic matter contains moderate levels of P (sorry, I can't
stomach blood meal :-)

The best lawn fertilizer for our area, imho, is the slow-release
"Sustain", available at places like Lowes. I've come to think that,
for an organic gardener myself who lives over the Edwards recharge
zone, Sustain may be a more environmentally sound lawn fertilizer than
compost.

Compost is not a fertilizer, it contains humates which is a necessary product
for good soil structure and texture. Putting down 1/4 inch on turf which has
been core aerated is not going anywhere other than into the soil. Sustane is a
great product, but LadyBug Brand is made by Sustane and has molasses coating on
the prill. Horticultural molasses contains approximately 15% Fe (iron).
Ironite has arsenic and is most useless. Chelated iron is much better for our
soils in this area.

"Sustane"... I walk past a stack of it in the garage every day and
never noticed they misspell it. ;-)

High phosphorous levels is a widespread, largely undiagnosed (or
misdiagnosed) problem for soils here in west Austin.. Stillhouse
Hollow http://www.ci.austin.tx.us/growgreen/stillhouse.htm seems in
most ways typical of west Austin neighborhoods built around the same
time, and virtually every yard tested in Stillhouse showed positive
for excessive phosphorous and potassium.

Compost provides soluble nutrients, beneficial microorganisms, organic
matter, humates ...and applied judiciously should be a core part of
responsible organic soil amendment. Depending on its composition
compost's nutrients may come primarily indirectly through the action
of decomposers. Some composts such as those based on poultry manure
quite high in soluble nutrients.

Compost should not be used on soils where phosphorous levels are known
or suspected to be high.

BTW, our Austin tax dollars have funded an extraordinarily useful
study, "Evaluating Potential Movement of Nitrogen and Phosphorus in
City of Austin Soils Following Varying Fertility Regimes: Greenhouse
Simulations". Open the Word doc at the bottom to see the tables:
http://www.ci.austin.tx.us/growgreen/fertstudy.htm .

I'm fortunate in that I have very deep soil. When we dug the pool, it wasn't
till we got to about 4 feet before we reached caliche.

Here it would take a weapon of mass destruction to reach 4'. :-) We're
over Edwards karst (I once discovered a small cavern while digging to
plant a Mex. buckeye). We have little springs and seeps al over the
place.

LadyBug brand can be bought at Home Depot. Sustane at Lowes.
Both 8-2-4 and have sufficient levels of phosphorous NOT to be
hazardous to our saturated with phosphorous soils.

I agree a product like Ladybug shouldn't add too significantly to the
problem. But any P will delay remediation in soils where high
phosphorous is a problem. It may also end up as runoff into our
streams and aquifers. Since phosphorus is rarely a limiting factor for
growth and bloom here it makes sense for most homeowners to use low P
organic fertilizers anyway. This year we'll use Sustane 10-1-2.