Shade cloth purpose by grade

[Veebs]

I see a lot of advice for shade cloths ranging from 30% to 50%.

Can you wonderful folks enumerate some scenarios for when you deploy shade cloth at different grades? In Zone 8a I have a 50% that some of my stuff is under, and a 70% I haven’t put up yet that I planned to put collected material under while it was still newly in the box.

Also, it seems a lot of bonsai nurseries are using shade cloth for everything. Are there any drawbacks to that?

 

[Headhunter843]

Great question. I'm in 8b with 50% shade cloth over my Maples and azaleas. With this heat, I'm wondering if I should replace the 50% shade cloth with something stronger. 70-75%?

 

[Wulfskaar]

I just got a "40-50%" shade cloth. I haven't used it yet. I'm saving it for the hottest days.

But I was wondering the same thing.

 

[Rodrigo]

I live in San Antonio and we have 95-100+ degree days regularly. I have a 30% shade over all of my trees (multiple types of elms, Japanese black pines, trident Maples, junipers, and olives) and then a 50% over a couple of Japanese Maples and a Brazilian Raintree. I think both are just the right amount of shade, still have short internodes but no leaf burn on any tree.
They stay on constantly pretty much from late spring to late fall unless it's super windy, then I take them down because a few have ripped in the past

 

[caffeinated]

I'm in Seattle and put up 40% if we're going into the upper 80s or higher. Mostly deciduous with some hemlocks under there. Conifers are mostly in full or morning sun. All happy, pushing new growth even with the upper 90s earlier in the week.

 

[Shibui]

The more shade the longer and leggier your new growth will be so always try to manage hot weather with proper watering and suitable pots rather than going straight to more shade.
I have seen many bonsai gradually deteriorate when kept under 75% shade all the time.

We get hot, dry summers here. 40C /100F and over for 10-20 days each summer and high 30sC most days through December, Jan and Feb.
I get by with 50% shade cloth (because that's the lightest I can get down here) over the deciduous, seedlings and smaller pots but conifers and developing trees in larger pots are in full sun all day all year.
Shade goes up some time in December when day temps start to go over 40C. I don't usually take it down again until close to leaf drop because leaves that have adjusted to shade will usually burn when exposed to direct sun again.