From

Location

Message

Date Posted

Winston Salem, NC

So I was talking to a professor at NC state the other day about shade cloth and temperature reduction. In his studies he only showed a temperature reduction when white or aluminet shade cloth was used in conjunction with hoophouses. Basically the black shade cloth was re-radiating heat and the plastic sheeting was holding the heat in due to a lack of air flow.

He did say however that while he hasn't done the studies...his feeling is that if you were using the shade cloth alone (without the plastic sheeting of a hoop house) that the black and white shade cloth would perform very similarly due to the heat exchanging capability of the moving air.

If you look at 22% white shade cloth, the thread count and spacing looks to be equivalent to the 40% black.

So that was a long walk to get to my question...

What is the governing mechanism that determines the percent shading?
Are you better off using 22% white or 30% black?
Does the 30% black allow more incident versus secondary reflected light to reach the plant for more efficient photosynthesis?
Which shade cloth between the 22 white and 30-40 black would create the biggest temperature drop at the leaf?

4/18/2013 12:50:47 PM

Colorado

Ive used 30%black,22%white and 12% clear.Ive done best with the 22% white.Temperature wise get the shade cloth at least 6foot height above plants to minimize any of them holding in heat(greenhouse effect).A world record pumpkin has been grown using 30% shade cloth.I would assume 40% will create the lowest temp.Dont know if 40% is two much shade uv wise.Also have to factor sun angle effect early and late in season.40% maybe 50%/55% morning,evening,spring ,fall if you know what I mean.

4/18/2013 2:45:37 PM

Winston Salem, NC

Thanks cojoe to add another question to this thread...

In my research, it seems like Gempler's has the best value when counting cost plus shipping.

Where do you guys order your shadecloth from?

4/18/2013 3:02:55 PM

Colorado

Google Greenhouse megastore

4/18/2013 3:09:51 PM

Colorado

Joe, between 12%-30% do they all protect from hail well, or are the higher % ones more thick and durable?

4/18/2013 4:23:14 PM

Muddy Waters

A plant only needs 50% of the suns rays to be 100% productive..My screen is white.I use a fan to create more airflow.I water at 2 pm to cool the soil & aid in cooling the environment.

4/18/2013 5:18:38 PM

Colorado

The 22% is better for hail-30% lets some real small stuff through

4/18/2013 5:41:03 PM

Colorado

The 12% is good also fo hail-got that through jamie(arvada boy) from italy.

4/18/2013 6:01:03 PM

Mnt.pleasant ,tennessee

What about a layer of black for shade & a layer of white on top to keep black cool

4/18/2013 7:27:17 PM

Midway, UT

The 12% is actually 14% that Joe was mentioning. What I have has stood up to a few good hail storms and the cloth is holding together nicely. The holes in the cloth are very, very small, but as Joe mentioned the material is clear, kind of like fishing line. Very strong. You can see the shadow on the ground under the cloth. I think that the 22% that Joe has is better for the Colorado climate but the 14% stands up well to hail and I think at even 14% there is a reduction in leaf burn.

4/19/2013 4:54:07 PM

midlands Uk

I know that this is my first year growing these but living in Tenerife tends to have a major disadvantage with sun and heat. ( currently 35 degrees + centigrade)
I have covered my kins with white sheeting but noticed how hot it was getting inside. My 7 yr old asked why we don´t use windscreen sun shades to cut down on the heat so we tried it with growth now coming back up on the kins.

Not sure if you´d all agree but it seems to be working here

4/25/2013 7:15:27 AM