Sunday, June 15, 2008

Exactly what was needed

We have had an unusual period of really hot dry weather and it has played havoc with the temperature in the greenhouse. I knew I would eventually need shade cloth, but had no idea of where to get one, or the value I needed. I had been using the nylon shade cloth that came with the flower house, and it did cut down on the light, but the temperature hit 100 degrees on a few occasions. That motivated me to get looking for a commercial quality shade cloth.
The first place I called told me they had no idea of the value of shading I would need to grow vegetables. They suggested I call local greenhouses and ask them. The problem with that is: that I have never seen a local greenhouse using shade cloth. They start seeds early in the year, and shut down for summer.
Further Googling found a large commercial greenhouse supplier that listed shading values for every plant imaginable. For tomatoes and vegetables a value of 40% was recommended. The literature said that the cloth was durable polypropylene and would actually cut down on heat.
The cloth arrived late Saturday, and I installed it and took the photo on Sunday morning. Much to my surprise it worked beautifully. At noon on Sunday it was one degree cooler in the greenhouse than it was out side. Using the nylon shade cloth it was so hot I would scurry in and mist the plants and get out as soon as possible. The only time I could take readings, or add nutrients, was just before sunset. Now I can see what was happening; the nylon was shading, but being dull black, it was absorbing heat and transferring it to the structure. The
polypropylene is glossy and reflects the heat and light away from the structure.
At this point I have abandoned trying to grow lettuce. The heat caused the plants to bolt to seed right from the seedling stage. The tomatoes, cucumbers and strawberries are all right, however, even though they like warm weather, it has been much too hot for them also.
Using my Dremel I rounded off all the sharp corners that might cause a tear in the cloth, but it is pretty tough stuff. A few tent stakes to tie it down completed the project.
It is nice to buy something and have it perform exactly like the literature on the website claims it will...

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