Greenhouse/hoop-house plastic question

Anyone ever use the HDX 6mil construction grade plastic that you can get at Home Depot on a greenhouse or hoop house?

On an overcast day, I put some over a structure in the garden we're going to grow under. The next day when the sun came out I was surprised at how much of a shadow it throws relative to full sunlight -- I knew it was not fully transparent but thought that afforded the structure some "privacy". Just wondering if anyone knows how much of a difference that much light filtering will make, or if anyone has used used that stuff before?

I've seen people use stuff that reduce the light by 60% also reduces heat and they still have amazing grows and barely effects the plants. But that's what I've seen, no complete knowledge of it tho.

kommano said:

I've seen people use stuff that reduce the light by 60% also reduces heat and they still have amazing grows and barely effects the plants. But that's what I've seen, no complete knowledge of it tho.

Click to expand...

Hey, thanks, I really appreciate the response. Since posting I've looked at more pictures online and visited a greenhouse, and it seems fairly standard that the plastic is translucent but not transparent, and cuts down the light.

While it seems "normal" for the plastic to reduce the light, my yard only gets full sun for 6-7 hours a day, so it might not be the best thing. I have others I may grow in pots outside the structure, they are getting a later start but I will have some sort of comparison, at least in terms of things like distance between nodes/stretching.

I'd go with a horticultural grade plastic from a greenhouse supply store. If it isn't UV resistant, it will become prone to cracking and falling apart near the end of your season. The stuff I'm familiar with at HD in the paint department is not UV resistant, but I'm not familiar with HDX specifically.

Bugeye said:

I'd go with a horticultural grade plastic from a greenhouse supply store. If it isn't UV resistant, it will become prone to cracking and falling apart near the end of your season. The stuff I'm familiar with at HD in the paint department is not UV resistant, but I'm not familiar with HDX specifically.

Click to expand...

I've tried the cheap 6 mil plastic and this was my experience, while initially cheaper probably more costly in the long run.

I hear ya -- but this summer I could spend $25, but could not spend $150 on plastic. The whole structure is sort of experimental, and after a season of seeing how it works and what needs improvement, I may be able to invest in some better reinforced UV proper greenhouse plastic. Or it might turn into a tool shed.

I was just wondering if there was anything beyond the UV resistance in greenhouse plastic, some make-up of the polymer that improved either the amount or spectrum of light that penetrated it compared with non-specific greenhouse plastic.

I don't know about 6mil plastics, but when you look at horticultural grade polycarbonate you can get a glazed panel that is made to diffuse light better and allow more light through, compared to the glazed panels you'd find at Home Depot. So it wouldn't surprise me if the more expensive plastic sheetings also provided better light quality. But if you're on a budget you might as well just give it a go and see what happens. You can always make changes along the way.

I've built 2 greenhouses using construction grade plastic, here's a couple pics of one of them. This is an old dog pen covered with 6 mil reinforced construction plastic that I bought at Menards.

www.menards.com/main/paint/drop-cloths-plastic-sheeting/poly-film/polar-plastics-6-mil-clear-poly-reinforced-plastic-sheeting-20-x-50-roll/p-1497092-c-8188.htm

Cheap & VERY durable, has made it through 3 Michigan winters now used as a storage shed. Can't make any comparisons with light penetration versus other plastics as this is the only kind I've used. I was very happy with it though and I built a bigger one using a portable carport but I haven't gotten around to taking any outside pics of that one yet.

Very good information, thanks everyone. This will be my first outdoor grow on my own, and on this particular property with its limitations. It's all a big experiment.