Lycaste-Anguloa how much peat?
 

I'm going to be getting my first terrestrials (a Lycaste and a Anguloa) soon. I'm planning on using a peat-bark mix. How much of the mix should be peat? I'm seeing conflicting sources that range from 15% peat to 60+% peat.

Btw, does too much peat make it too acidic for the roots or something, or is it just a drainage/aeration problem?

I wouldn't consider Lycaste/Angula terrestrial... They have fine roots so like to stay somewhat damp, but they're still epiphytes - and need air, a well-drained mix. My own success rate, especially for the species, is in plastic baskets with sphagnum. But that's under my outdoor conditions - they hang, they get lots of air. I think I'd skip the peat, just use small bark, unless you need more moisture. I really doubt that they need any extra acidity. If growers in your area do use peat (do seek out orchid people in your area, get local knowledge), I would suggest keeping it to the low side.

I would not use peat in general due to sustainability issues. In order to gather peat, peat bogs have to be dug up destroying vegetation and the fragile wetland and bog ecosystem. Peat also grows extremely slowly at only 1 mm per year in even the healthiest of bogs. Peat bogs are also the most efficient carbon sinks in the world and the conservation of these wonderful and majestic wetlands is critical to solving the climate crisis.

Peat bogs are also important habitat to many temperate orchid species!! :D:D