Covering?

I am about to order the film for my greenhouse, and I was wanting to get some pros and cons of clear vs white from some of you that have some experience. I understand that the white defuses the light and lets less light in (between 55 and 75 percent according to the manufacturers) and the clear lets more light in, and doesnt defuse it, so more shadows. So in reality which works better? Thanks for the help.

No opinions? I worked on the foundation this weekend, got about 1/2 of it done. I have the frame built and I am leaning toward white plastic since here in AZ although we have VERY cold winters and a short growing season we have a lot of Sun. What do you think? Thanks Van

Finished the foundation this weekend, and got the frame on it. I also ordered my top vent and figured out my door. Next I am going to build my grow beds and my water tank, order my side vents , plastic, pond liner and insulation for the north side. Still looking for opinions on clear vs white plastic. I am leaning toward the clear, since if it turns out to be too much, I can always whitewash it. Your help would be appreciated. Thanks Van

Hi Van,
I'm also interested in this question, I don't have a great answer but I'll give my input. It has been shown that most plants grow better in diffuse light, i.e, when it's cloudy. Based on this, if you're living in a cloudy climate, like back East, the light is already often diffused by the clouds, so you would want maximum light transmission through your glazing, suggesting that clear would be best. But if you live in an exceptionally sunny location, you may want to diffuse some of that light while entering the greenhouse. Less overall light may not be a bad thing if what's available is more usable and you're not limited by lack of sunshine.
Also, I think which is best sort of depends on the design of the greenhouse. It sounds like you are building an earth sheltered greenhouse with an insulated north wall? If so your overall glazing is less, thus you may want more transmission, i.e. clear glazing. What is the ratio of growing space versus glazing?
http://www.builditsolar.com/Projects/Sunspace/sunspaces.htm
This is an awesome website with some good info and links that could help out. I'm no expert, but I'll be building at least two greenhouses this year, so I'm in the middle of doing research to find out what works best in different situations.

Hey Guys you should look into Solexx...
There is a thread over here where Zach gives some info on it Zach Weiss, earth powered greenhouse

I am thinking of spec'ing this for an upcoming project. They sent me samples and really like it. Zach mentioned that he is a dealer and can get you a permies discount.

Hi Guys; I have had sollex on my greenhouse for 3 years now and I can't say enough good about it ! This stuff is GREAT ! The rolled version can be shipped free up to apx 110 linear feet , can be bent in any direction,thus no air gaps. An R value ! The opaque coloring makes for even lighting with no hot spots. I use a 30 % shade cloth during the hot months. The only (problem) I have found is keeping the open ends of the corrugation sealed ,thus creating the dead air space required for the r value. I have had to reseal with silicon each year so far, but less each year as i get a better coverage. Initial cost is steep , I paid $8 a linear foot delivered for mine , apx $800.00 for my 12x20 greenhouse but with a ten year warranty on the uv and possibly much longer I find it to be very cost effective! I would never go back to a sheet plastic covering again. As a side note I kept my greenhouse heated all winter with a rocket mass heater this year and holy cow ! They work awesome! Using the mass as a raised bed for starts makes the little baby's so happy they pop up in no time!