Mini Green House to finish flowering

I made this over the weekend to protect from some early frost that we got (went down into the low 30's in Northern MI". This was just temporary I have a heat wire that you would use on your roof to keep the snow and ice from building up in your gutters. Worked great but now it is time to move on and try something a little better planned. I have two plants that are flowering late. One is a Nirvana White Widow "The bigger one on the left". The other is a Nirvana freebie that I have no idea what it is. I threw a sheet over the top for the evening. It was actually nice and warm when I pulled off the sheet the next morning.

I am considering making a hoop house to get me through flowering. I don't want to spend a lot of money and only need it to finish flowering. The frost we got was way early for this time of year. But I am pretty sure I will see it again before I get done. The mini green house will be 6 feet long by 3.5' wide and 5.5' tall. I have some constructor grade plastic on hand "see pic" that I am going to use.

I will only be able to tend it on the weekends for the most part. My worry is humidity. The heat wire I can control on an ISO bar timer that I have. Would a small clip fan be enough to keep the humidity down? Any ideas or suggestions would be appreciated...

Maybe a large bed sheet in the evening will be good enough with the heat wire. I can get rid of the plastic. I can get some poly-tube to dome the top. I might be able to get the wife to take the sheet on and off each time we have frost. I wouldn't ask for much more though. I can already hear the bitching...

Sounds good... I think I'm going to have to do the same thing... I searched for DIY greenhouses on RIU and found some really good tutorials... Alot of them use PVC as a frame and that clear contractor's plastic that you have. I would try to only use a single layer of the plastic to get the most light penetration possible.

I think you will be alright with humidity if you make windows in the GH. If you can keep the windows open during the days and close them at night when the temps start to fall and open them again when the sun comes up you should be fine. The fan will help, but I'm not sure about how big the fan you are talking about is.

The heat wire you have seems to be perfect. If you can turn that on at night after the sun goes down and close the windows I'm sure you will be alright. I don't think you would have to keep it on all night, but just enough to get it warm in the GH and keep it above freezing. MJ is very resiliant and will survive light frosts and plants your size that are healthy can even survive a hard frost. So you are looking good.

Being that you have the heat wire and fan I'm guessing your girls are near your house or an outlet of some sort, possibly from a shed. You can always bring them inside on nights you are expecting a frost. I don't have any experience with a greenhouse so you should definately get a second opinion. Im intrested myself because I'm in the same situation, not yet but I will be due to late flowering so I'm looking foward to more advice....

Nice grow by the way! Good job!