"Jeffrey L. Kline" wrote in message
...
I've used Bayer products and find them to be of high quality. I
don't use the systemic system, just 'cause I think topical
application of insect and fungus/black spot control to be more
effective.

There are a ton of articles on line providing the pro's and con's
for both synthetic (generally petroleum based) and organic
fertilizers, including American Rose Society.

With 3000 square feet of garden, I find granulated fertilizer an
real benefit. Its easy to apply, consistent in its composition, and
cost effective.

I think the main issues of synthetics from my experience is the salt
build-up in the soil (and run-off in the water, if you're not
careful), as well as increasing pH. Both have a tendency to
decrease the plant's ability to take up the nurturance in the soil.
(Martin and Gail, in reference to your "roses are busting out all
over" thread, this is why, so I'm told, that they recommend you
replace soil when placing a new rose in an old rose site.)

I think you've got a good point there. I try to
use a mixture of organic and non-organic
sources so I'm not quite as worried about
soil conditions, but it might be a concern for
a new rose in an old spot. There's also the
potential problem of disease. A rose that doesn't
last long after planting must have something
wrong with it. Mostly, I think in my case,
it's a matter of roses that can't deal with the
high heat. Roses used to the heat - like Teas -
do great with little effort on my part. And
yeah, I'm planting more and more Teas...

There are several products that can reduce salt buildup, including
gypsum. It has the additional benefit of clumping clay, so you get
better root aeration. In addition, I monitor my soil's pH and
adjust it to 6 to 6.5.

I add gypsum my soil because it's heavy clay
and I've read gypsum helps with drainage. We've
had floods here, and as far as I can tell I haven't
lost any roses because of too much water.

I also use horse manure based compose, but I find it is not very
high in nitrogen. The wood chips used in stalls these days are very
high in carbon, which actually leaches nitrogen out of the soil, so
I add nitrogen to the pile while I'm composting it.

And that's my main concern with most "natural" fertilizers. Its
really hard to know how much of what is in it, and it varies from
batch to batch. As a result, you can never be sure you're providing
all of the substrates the plant requires. (Well, I guess if your
plants are big, green, healthy, and full of blooms, you must be
doing something right.) Also, if you have a big area, it can get
quite costly.

Hope this helps

Jeff, Southeast Michigan, Zone 5

Gail
near San Antonio TX Zone 8