This section is from the book "The Gardener's Monthly And Horticulturist V23", by Thomas Meehan. See also: Four-Season Harvest: Organic Vegetables from Your Home Garden All Year Long.
In regard to shading greenhouses, I found it paid better to mix up a lot of clay'with a little indigo or bluing to the consistency of thin paste and wash the glass, than to use lime white-wash, but ordinary lath shades if nailed on pretty thick answered better than anything else. Of course this would not answer for an orchid house, but for all ordinary purposes it is No. 1. I might say with lath shading they should be placed so as to have the rays of the sun continually, changing as the sun travels to the west. A little sunlight is certainly beneficial to nearly all plants, and if the house is well ventilated no great or oppressive heat need be retained in the house. The mud paste will require renewing after each heavy rain, but in fall it will wash off without much trouble, and very little injury to the putty.