Subject: Re: powdery mildew
From: <don@bio-organics.com>
Organization: Internet Access of Ventura County 805.383.3500
Date: Tue, 23 Sep 1997 12:50:08 +0000
Message-ID: <MOD$970924.3310@rec.gardens.ecosystems>
References: <MOD$970917.28136@rec.gardens.ecosystems> <MOD$970918.10699@rec.gardens.ecosystems>


Bill Robinson wrote:
>
> William D Hulet wrote,
> >
>
> > I would have thought that mildew wouldn't grow in a place that absolutely
> > roasts on hot sunny days---. I have to water the planters twice a day to
> > avoid water stress, and I haven't been thinning the leaves as much as if
> > I had more room. The soil is half potting soil and half compost and I
> was
> > also putting blood meal on the soil every week (friends were telling me
> > that the plants would suck the soil of all nutrients really fast).
>
> Powdery Mildew goes for young, tender foliage. My guess is that you not
> only have an overly rich soil but you are also over-feeding, over- watering
> and causing an over-abundance of young, tender growth. I'd cool the feeding
> and the twice a day watering, get your potting soil mix a little on the dry
> side,
> and start washing off the foliage with plain water. You are probably too
> late
> to really correct the situation but this would still be your best shot.
>
> Blood meal can run as high as 13% nitrogen which is really hot. My
> experience
> is that there are more problems caused by too much feeding as there are by
> feeding too little. I think a better ball park range would be 75% _garden_
> soil
> / 25% potting soil and a very light feeding of a dilute fish emulsion
> (about half
> the strength recommended on the label) no more frequent than once a month.
>
> There is the perception that organic gardening works behind vigorous growth
> and
> if you get vigorous growth that you will also get disease and pest
> resistance. I think
> the idea is bascially true but only up to a point. You can push too hard
> and cause
> watery growth and stress causing greater vulnerability to problems with
> pest and/or
> disease.
>
> Bill

Bill, I would differ just a little with your observation, in that I
consider a truly healthy well-grown garden plant to be more on the
shorter, stocky, side than having real vigorous growth. I fully agree
that overfertilizing is the cause of many insect and disease problems,
and I think it may be due to growers misunderstanding the term "rich
soil".

A good soil is rich, but in biolife - beneficial algae, fungi, and
bacteria - feeding on abundant humus and converting nitrogen,
phosphorus, etc. into forms plants thrive on. Making the soil
artificially rich in individual nutrients, whether synthetic or natural,
is a big strategic mistake.

We so often hear a gardener moan, "I gave the plants a lot of good food
and watered them faithfully every day - how can they be dying?". The
answer is that plants can be made sick by overdosing with plant food,
and roots of many plants will rot if kept too wet.

Easy does it - tough love feeding - and, make 'em beg for water a
little.

Don Chapman
Bio/Organics Supply Center
Camarillo CA
<http://www.bio-organics.com>