Tuesday, July 28, 2009

Emergency measures in a heat wave

This wasn't my idea of a second post, but on the way to the forum a heat wave struck and I began waking each morning to more and more curled leaves and listing fronds. With temps the past few days soaring over the century mark, not at all our norm here in Portland, I needed to do something dramatic and quick. The above picture is the heart of my solution. This a tent of black woven polypropylene material - Aluminet shade cloth.

Typically our temperatures dance in the upper 80's and low 90's in late July and early august - with an occasional day above 100. Generally any temp is accompanied by some cloud covered, even if scattered throughout the day, and a breeze. This heat wave is stifling, sitting over the valley not a cumulus in sight and suffocatingly dead air. The sun just beats down on life large and small.

I chose Aluminet for a couple reasons, but primarily becasue the strands are twisted, so it reflects diffused light from many directions. I needed well diffused light to ensure even the smallest lower level plants received ample light while still continuing to be protected.
Aluminet provides several benefits, including 50+% radiation/shade protection. This is the same cloth-like material many local nursery growers use. It comes in six foot wide sections and lengths up to about 230 feet on a roll. I took the remainder of a roll - 200 ft.

In addition, I purchased three bags of grommet sets (6 per bag), and a 100 unit bag of zip-ties. The grommets were critical in helping string the entire tent up via ropes to my roof and the existing fence on the north and east sides. The zip-ties were needed to "sew" the fabric together since each width was only 6ft. The resulting tent became approx. 18'x22'.

The last element was to prop the central section up high enough to allow the taller maples and Hinoki cypress gracilis breathing room to continue growing upwards. I used eight foot 2"x2" poles I had left over from another project to do the job.

What I have learned in the past couple days is as this heat lingers - even at night - propping the tent up higher not only gives the trees canopy space, but also provides for better ventilation - which I had not originally taken into account.

The whole project cost me about $150 - a small price to pay for the dozens of trees and small plants I have commited to insuring a future in my garden.

Side Benifits:
1) the tent maintains greater humidity underneath - which has helped many of the small ferns and ground mosses and lichens I had seeded the area with
2) the tent slows evaporation and reduces my water requirements
3) I moved many of my small potted maples and conifers under the tent and reduced there rapid drying out
4) birds like bushtits, chickadees, Anna's hummingbird, song sparrows and western towhees are using the shade as a respite from the sun and feeding on the increase in insects that are trying to benefit from the added shade and moisture

Since my garden had no established large trees for shade I have decided to keep the shade tent up, and will probably extend it. While not the ideal look, I'm in this for the long haul and the trees I have planted and will plant this coming winter, to form the eventual shade architecture, will take a few years to establish the required canopy height and breadth - until then the shade tent will stay in place.

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