Hi!
We're new here and hoping to gain some advice and help. We live in southern coastal Georgia and struggle to keep plants from withering, scalding, dying or going dormant.

We just moved to a new home where there is no shade in the backyard so the plants are easily getting sun from 8am to 5pm with temps steadily at 90 plus. We've been getting afternoon pop up showers for 2 weeks now. Even our most heat tolerant are just dying left and right. Some went dormant. Some appear as if they'll bolt.

The temps aren't unusual to us but having no trees or shade is unusual at our new location which has zero cover. Would a shade cloth at 30% be beneficial? Would it be beneficial to have up the entire growing season (our first frost if at all is Nov 25 early December and last about March 4 but we do get some zone 9 temps with no frost years)

We're also an east to west backyard situation with the sun coming in the east in the morning.
Our plants up front get 5 hours evening sun and are doing much better including Clementine and Lemon dwarfs.

Thanks so much for any any any advice on shade cloth and the best percentage

30% shade cloth would be useless!

I lived in Florida for 9 years and grew mostly orchids. I was growing "sun loving orchids" that I thought would be fine. I was wrong.
The heat and sun intensity are just too much. If the sun is way too strong, you'll need more reduction.

I used both 50 and 60% shadecloth. If you google it you'll find that it is not too expensive. If it allows your plants to grow and produce, it is worth it.

For my orchids, I wanted 3,000 foot candles of light. Foot candles are a measurement of intensity. If Florida light was say 5,000 foot candles and I tried to reduce it by 30%, it would still leave 3,500 foot candles. Way to much! And then you have to consider the duration of light, how many hours is it that bright?

@Izzy81, I concur with @BigBill, 30% shade is probably insufficient for your southern coastal Georgia backyard. I'm assuming you've asked about 30% for a particular reason, maybe you are trying to economize and you found an inexpensive source. If that's the case, don't be afraid to consider doubling or tripling the layers of shade cloth you use. This may be easily done, depending on how you support it. You can even mix and match, 50 + 30% layers for example. A double layer of 30% may not provide 60%, but it would probably offer something like 50 to 55% shade, and that may be adequate to get some shade plants started. Start with fast growing shade plants, and replace them as desired with slower growing more desirable species.

Also, if you're using a clever shade cloth support system, you can peal-off one layer of 30% as needed for early and late season growing. You can also flip shade cloth over periodically to even-out its UV exposure and lengthen its life. Shade cloth layering also offers some redundancy; if one layer rips or is otherwise lost, you'll still have another to fit. There are some real advantages to layering. For true economy, be sure to design your support system and shade cloth attachments (grommets versus staples) with permanency in mind. But bear in mind that a single layer of 60% will generally be cheaper than two layers of 30%.