Removing shade cloth
 

As evidenced in previous threads, I'm a new greenhouse owner. Filled with questions and probably investing too much time worrying about details. I live in Wilm., DE (near Philadelphia) and my current inner debate is when should I remove the shade cloth? Since the sun's rays get less and less stronger as we move into fall, what magic moment do you decide to remove it? By the same token, as tree leaves near the GH fall, more light will be admitted so maybe I need to wait longer. I'm still reaching low to mid 90's during the day with the shadecloth on.

I also have a solar blanket and am wondering when I should consider putting that on. Current ambient outside temps are running between 52 and 62 at night and 72 to 82 during the day so I'm sure I don't need the blanket for awhile.

I find that when to take of the shadecloth is more of a sense of the change of seasons more than anything. Mine came off in the 2nd week of September when temperatures started to drop. In your conditions, when the weather feels like the beginning of fall, take it off. If it's a bit early that's no problem as the sunshine isn't as intense as during the summer, and the plants will appreciate the extra light before winter.

I also took my shade cloth off although it wasn't until yesterday. I replaced the shade cloth with it's winter blanket which is currently 4ml plastic until I can get a solar blanket. I figure that the plastic would help cut down any sharp sunrays we may get, and our rainy season is coming on so I wanted to get as much solar heat as I could. I would watch the temps and take it off when it is either too cloudy, or the temps are dropping too low. Could you use a light meter to help you decide? I picked one up for less than $20 at the local garden store.

I do have a foot-candle meter, although it only goes to 2000. My day temps are going to be in the mid-80's (outside) for another week according to the weather report and sunny. It's still pretty strong light here in the northeast. I suppose in another week or so it will be time.

This will be my second winter in the greenhouse and I have the same concerns. When to take off the shade cloth, when to close the vents and on and on.

This spring, when I added the shade cloth, I decided it would be a good thing to keep a journal or at least write it on the calender when I add or take off accessories.

Hopefully, that will give me some guidance next year.

Interesting subject because I have the same question. I am measuring the light levels both inside the greenhouse and outside. Peak outside levels (on sunny days which is all we have, no rain ever) has not changed since mid summer. They run 10500 to 11500 fc but obviously for shorter periods as the day length gets shorter.

Inside in areas where the shade cloth does not protect near the end walls, I get 5000-7000 fc. I realize that polycarbonate has a stated transmission of 85%, but the unprotected sections are getting light through a vertical wall so the light is striking it at an acute angle. In the protected areas (50% aluminized shadecloth), I get about 3000-4000 fc at peak time of day, but this peak has decreased in length a lot since last month.

I'm waiting a little longer for now to remove the shade cloth, but I'll be glad to hear other recommendations.

Jim, Lexington,KY

I have my aluminium type shade cloth inside the green house and it is in sections mounted on plastic pipes. So, I can remove the cloth on a section at a time. My greenhouse faces north and the northern most section was never added this year.

While I did have a burned leaf or two, it added extra 'hanging' room for catts. Now I am removing or rolling back sectioned number 2.

I hope by doing it in sections vs just taking the whole thing off/out, it will give the 'girls' a chance to toughen up slowly and not get burned.

Sorry about the no rain, Jim. :( Arkansas went through that last year and several years before and it's very sad to see the outdoor plants such as elderly trees suffer and die. Hope you get rain soon.