10-08-2009, 06:54 AM
Greenhouses are expensive. People wouldn't buy them if a shade house fulfilled all the same functions. There are tons of greenhouses on the island. Instead of asserting they are unnecessary, another approach might be to assume they have a value as so many people invest in them.
One of the first things I was told when I moved here is that I couldn't grow most tomatoes outside a greenhouse, because there is a wasp that stings them and I think lays its eggs. Cherry tomatoes seem relatively immune. Those lovely Kamuela tomatoes without blemishes are greenhouse grown.
I do not pretend to know all the reasons that growers use greenhouses, but some occur to me. Certainly there are areas where it rains so much that there are rot issues and one would wish to control the irrigation. There are colder areas. A greenhouse provides more than warmth; it provides the ability to control the whole environment, as kani'lehua said. Some crops will not succeed here without controls. A shade house provides a filter for plants like orchids that don't like direct sun, but it doesn't keep out the bugs or remain a constant level of humidity and temperature. I wish I could afford one.
One of the first things I was told when I moved here is that I couldn't grow most tomatoes outside a greenhouse, because there is a wasp that stings them and I think lays its eggs. Cherry tomatoes seem relatively immune. Those lovely Kamuela tomatoes without blemishes are greenhouse grown.
I do not pretend to know all the reasons that growers use greenhouses, but some occur to me. Certainly there are areas where it rains so much that there are rot issues and one would wish to control the irrigation. There are colder areas. A greenhouse provides more than warmth; it provides the ability to control the whole environment, as kani'lehua said. Some crops will not succeed here without controls. A shade house provides a filter for plants like orchids that don't like direct sun, but it doesn't keep out the bugs or remain a constant level of humidity and temperature. I wish I could afford one.