Healthy soil and sustainable growing

["TradingPostPaul" <tradingpost@riseup.net>]

Very on topic, anything and everything about greenhouses and season
extension in general. Last year I tried something new (for me) with plastic
draped over tomato transplants in beds inside a plastic covered greenhouse.
Started this setup in April with two months yet to go before last frost. I
had 2x3 frames over the beds to hold the plastic up off the tomatoes. It's
easy to fasten light support frames to wooden bed frames. I grew the
transplants in a smaller, warmer greenhouse against the house, heated by a
small electric heater. After succeeding with the double protection I
learned of Eliot Coleman's technique, using row covers over his greens
inside a greenhouse. He said he got the idea of "layering" from noticing
how people put on layers of clothing which they can remove or add to as
need arises. Covered beds can hold a lot of heat from the daytime. Here in
high desert central NM we have very wide diurnal swings, easily from the
teens at night to 50s or 60s daytime. So wherever we have enough sun and
warmth in the daytime, we look for ways to capture and store the heat
through the night. Certainly black stone or concrete will absorb and hold
more heat than dirt. Adding heat is expensive.

Since relocating here I've only got a small seedling greenhouse going, what
with everything else to do, about 8x12 footprint. We're getting two solid
days and nights of 55+ mph winds now, unbelievably aggravating. But the
greenhouse isn't even wobbling, built for high winds. With luck we can
afford to start adding on an 18x50 by April. Big IF.

paul tradingpost@lobo.net

*********** REPLY SEPARATOR  ***********

On 2/24/2007 at 1:15 AM Dieter Brand wrote:

>Bobby,
>
>  I don’t have any experience with underground structures,
>  but I’m not sure that you’ll get enough sun-exposure if you
>  cover your greenhouse with an earth-roof. It may be OK to
>  dig the N, NNW, and NNE directions partly or completely
>  into the ground; however, anymore than that is likely to
>  result in one-sided growth.
>
>  Personally, I have been thinking about a passive-heated
>  greenhouse for a number of years, but so far haven’t had
>  the time to put it into practice.
>
>  My thinking goes in the direction of using the principle of the
>  trombe wall for building a greenhouse base of black stones
>  on a South-facing slope. Specifically, I would create a level
>  base on the slope by building a base of black stones that
>  would extend beneath the entire width of the greenhouse,
>  thereby warming the soil from below. A glass pane provided
>  at a distance in front of the South-facing base of black stones
>  would increase the amount of heat energy first stored by the
>  black stones during the day and then gradually released during
>  the night.
>
>  The only thing I haven’t figures out is if the black stones would
>  need to be in one piece across the width of the greenhouse,
>  or if the heat would be transmitted from one stone to another
>  if these touch each other or if they are bound by some sort of
>  medium, like sand for example. Any ideas?
>
>  Regards,
>  Dieter Brand, Portugal
>
>  PS: Geothermal heat pumps can be tricky.  A neighbour who got
>  a very fancy geothermal system for heating the house installed
>  at great expense, finally got a wood stove after freezing for 3 winters.