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market-farming - Re: more greenhouse questions!

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  • From: "wiediger" <wiediger AT email.msn.com>
  • To: "market farming" <market-farming AT franklin.oit.unc.edu>
  • Subject: Re: more greenhouse questions!
  • Date: Wed, 31 Jan 2001 19:13:30 -0600


We are. there has literally been no long term research in the US on this
subject. Any time light levels are low, there is a significant chance that
the growing plant will accumulate nitrates - especially known nitrate
accumulators such as spinach. There have been some 'snapshot' studies done,
but nothing showing actual seasonal changes. We submitted a grant request
to OFRF this past year to study exactly that - recording light levels each
day, min and max temps, and bi-weekly nitrate levels in 4 different types of
crops. It was fairly extensive, very detailed in data. We wanted to record
how the nitrate levels changed as the light levels changed. We had planned
to post data on the website in real time for those interesssted in the
progress. Then, we wanted to run it for an additional year if there was a
nitrate problem, changing our fertility program to try and help slow down
the accumulation. We were not granted the funds for research, and from the
comments, feel that they thought 'farmers' weren't capable of this type of
research - that it takes 'university people' to do this. 'Course, the
universities aren't doing this type of growing, farmers are.

There has been quite a bit of research in Europe, where this type of growing
is more common, but it is difficult to extrapolate to this country -
climates are different. Hopefully we'll still get a chance to check this out
someday - but the tests, light meters, and time to record and analyze data
are too costly for us in our operation. We just tell people not to eat
spinach salads every day - and they don't.

Alison Wiediger
Au Naturel Farm
http://aunaturelfarm.homestead.com

----- Original Message -----
From: "cathy mcgregor-smith" <mcsmiths AT elgin.net>
To: "market farming" <market-farming AT franklin.oit.unc.edu>
Sent: Tuesday, January 30, 2001 8:44 PM
Subject: Re: more greenhouse questions!


> is anyone concerned about nitrate accumulation when growing greens etc in
low light
> conditions???
>
> robert schuler wrote:
>
> > A few more tidbits
> > Double layer inflated plastic will eliminate wind damage but not help
keeping plants
> > warm in unheated house, in my county we have thousands of single layer
houses for
> > holding perennials that stay put by eliminating the ridge pipe, the
plastic squeezes
> > down tighter without the ridge, you can also make poly tie downs with 4"
wide strips of
> > plastic placed over the house at 10 ft intervals...
> > Ventilation, if you use one year poly then just cut holes about 16"
diameter in the
> > sheet every 20 feet and leave a small amount uncut to act as a hinge
then you can tape
> > the hole partly shut on coldest nights this is only done in late spring
before you
> > remove the sheet all together, if you cut holes be prepared for water
damage to any
> > plants below.
> > I use a double layer house with supplemental 100000 btu propane heat set
at 35 deg. this
> > really improves the quality of the crop but is costly even at the low
temps,burning
> > about 20 gallons a week but worthwhile because you must have quality if
you are selling
> > to a supermarket for example, greens or lettuce with tip burn from
constant freezes just
> > won't holdup in the market
> >
> > Infrared sheeting really makes a difference and at 25% more in cost, its
very cost
> > effective but it seems to be sensitive to damage more so than regular 4
years poly, you
> > will gain about two extra hours of stored warmth after sundown compared
to regular
> > poly.
> > Use fans to keep constant air movement this will keep plants dry and
prevent disease
> > like botrytis, I have been using Patton brand 18" fans that are quite
inexpensive and
> > very powerful and have been running them nonstop in some cases for three
years.
> > Good luck to all
> > Sunny Meadow Farm
> > Bridgeton,NJ.
> >
> > ---
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>
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