Page 1 of 1
Does shade cloth help to prevent sunscald?
Posted: Fri Aug 04, 2023 12:33 pm
by bower
I've been having some leaf loss this season when fruit are still growing and a lot of them are completely exposed to the sun.. I am already seeing some sunscald on one of the earlier ripening, and I've been thinking of making artificial leaves to hang above the plants.

then I thought about shade cloth which people use in the south, and I wondered if that's the key to avoid sunscald?
Anybody with experience, do tell. Give us the fine points of how to use shade cloth effectively, if you will!
@Harry Cabluck I'm pretty sure you mentioned using shade cloth. Your advice will be appreciated!
Re: Does shade cloth help to prevent sunscald?
Posted: Fri Aug 04, 2023 12:41 pm
by worth1
It only needs to be set up on the south side of plant at right angles to the suns rays for best effect.
Or at least some sort of angle.
Your latitude and angle would be different than mine by a good deal.
This time of year it's almost flat.
Re: Does shade cloth help to prevent sunscald?
Posted: Fri Aug 04, 2023 1:15 pm
by Harry Cabluck
These tarps cut out half the sunlight. Had no problem with sunscald. Prolonged daily ambient temperature above 100-degrees in mid-season, however, prevented fruit-set. Had an average harvest this season, perhaps three-quarter bushel from 12 plants. Tarps are white mesh. You can see how carabiners connect the tarps to overhead cables. Planting into each of three raised beds is done about a week to ten days apart. Translucent drum liners are shown in the middle row. The drum liners are used early in the season as individual greenhouses.
Shade tarp.jpg
Re: Does shade cloth help to prevent sunscald?
Posted: Fri Aug 04, 2023 2:01 pm
by bower
Thanks so much, guys. Great pic @Harry Cabluck of your setup.
I thought we might not get a harvest at all due to the early cold and then extremely humid heat, but there was a window of opportunity when the plants set a lot towards the upper canopy, before we got into the heat warning conditions.
However the top rows couldn't set and they're quickly losing foliage cover for the fruit below .
I quickly pinned up some row cover today after removing yet more funky leaves, and let it hang in front of the worst affected row. The greenhouse has wires for attaching tomato support so that is easy enough, but I should probably pin up the bottom end to be at right angles. Don't want to block all light nor make anything difficult to take down (what are the chances of bringing on more cloudy weather?) so I will aim for something partial and easy, and hope that's enough.
Really great to know that it works for you Harry, and no sunscald. Sorry you didn't get a heavy crop - any crop at all is a feat with the extreme weather you've been having! Awesome setup.
Re: Does shade cloth help to prevent sunscald?
Posted: Sat Aug 05, 2023 12:44 pm
by Harry Cabluck
Cleared.jpg
Sorry for your sun-scalding issues. Perhaps cheesecloth might be stretched over the sunny side of plants. This part of Texas anticipates triple digit temperatures until mid-September. Those tarps were removed and stored, and the garden cleared of everything before August 1. Global warming is causing a need to change when to sow tomato seeds for this small garden in Austin, Texas. Previously, seeds have been sown on Jan. 1. Now plans are to sow before Christmas. This photo shows how the cables are suspended to accommodate the tarps. An inch and 3/4 of rainfall will fill the 800-gallon tank on the left. Cold frame on the right holds about 15 six-inch pots.
Re: Does shade cloth help to prevent sunscald?
Posted: Sat Aug 05, 2023 1:17 pm
by AZGardener
I couldn't garden in the Summer here without it. Days and days of 110-115F (43.3C), most everything would be cooked.
Re: Does shade cloth help to prevent sunscald?
Posted: Sat Aug 05, 2023 7:25 pm
by Cole_Robbie
I remember throwing buckets of muddy water onto my hoophouse...free shade paint.
If you do buy shade cloth, it comes in several different percentages of light transmitted. I had some that was mylar on mesh netting.
Re: Does shade cloth help to prevent sunscald?
Posted: Sat Aug 05, 2023 8:14 pm
by bower
Well another interesting thing, the foliage disease I've been having is Alternaria, brought on by the higher temperatures and humidity going on for weeks at a time. But as I was reading about it today I discovered that high UV also helps germination of the Alternaria spores. So the right kind of shade could actually help prevent the defoliation that is causing the sunscald in the first place.
I wish I could just start my seeds earlier, but climate change is giving us the yoyo up here.
Kudos Harry and
@AZGardener for your determination and ingenuity to make it happen when it can.
@Cole_Robbie I remember when you were doing the muddy water.

If I had a regular hoop with plastic it would be different, the glass glazing is really deadly when the sun shines. UV has been 9 and the glass takes it all in. Although my outdoor plants are pretty badly affected as well, I think the plastic does dissipate UV too, doesn't it?
Re: Does shade cloth help to prevent sunscald?
Posted: Sat Aug 05, 2023 11:42 pm
by Cole_Robbie
It depends on which poly you buy. For my second structure I got the light diffusing poly that is opaque instead of clear.
Re: Does shade cloth help to prevent sunscald?
Posted: Sun Aug 06, 2023 8:17 am
by Kurt
image.jpg
I got this roll of UV resistant cloth that is 6 ft by 20 foot.The pre grommet shades are expensive.I make frames from 1x2s or bamboo.The problem we encountered are those winds that will lift them like a sail and cause a lot of damage if not secured.
image.jpg
Re: Does shade cloth help to prevent sunscald?
Posted: Sun Aug 06, 2023 8:19 am
by Kurt
Re: Does shade cloth help to prevent sunscald?
Posted: Sun Aug 06, 2023 8:20 am
by Kurt
Sorry about the double
Re: Does shade cloth help to prevent sunscald?
Posted: Sun Aug 06, 2023 3:18 pm
by Cole_Robbie
That's a good point, Kurt, about grommeting and price. When I was shopping custom size shade cloth, it looked cheaper, but the additional fees to install grommets and hem the edge almost doubled the advertised price.
Re: Does shade cloth help to prevent sunscald?
Posted: Sun Aug 06, 2023 3:25 pm
by bower
Very nice @Kurt . I love the look of the hanging frame. We have wind issues too, big time, but the cloth could really work in the greenhouse. I do have a sewing machine too, so no excuse not to hem it myself or install grommets.
Re: Does shade cloth help to prevent sunscald?
Posted: Sun Aug 06, 2023 3:34 pm
by Kurt
I gots me a nice old school grommet punch,Get some coals,put a 3/8 piece of iron in it.flip slow burn,cauterize,when mid kool grommet time.Custom sizes all day long.In between the grommets in the flipped we use a electric glue gun.I use stainless steel snap in swiveling With the green coated plastic cables and ssSteel connectors.Needs to be able to move during seasons and emergency’s.