How root bound do orchids like to be?

[Mercurianmad]

How root bound do orchids like to be before I it’s time to repot them?

Does it vary by species or are they all pretty similar?

In the slotted pots they often creep out the sides of the pot, but if the medium is good and their roots are not filling the pot I don’t repot them. Is this the best course of action?

[estación seca]

There are lots of questions in your question. I don't repot anything unless the medium is breaking down or the plant is too big for / outgrowing the pot. I don't repot unless the plant is just beginning to make new roots. I don't try to put roots that grew into the air down into the medium when I repot.

Most people use a pot big enough to acommodate 2 more years' growth. That depends on the individual plant and how it grows.

Medium breaking down depends on the medium you use and how often you water. Paphs and Phrags need to stay moist, Phrags usually wet. Bark breaks down very rapidly under these conditions so people usually repot these genera every 1-2 years. High quality bark like Orchiata or New Zealand bark may last longer, and when used with Cattleyas, which usually are allowed to get nearly dry between watering, it may last much longer than 2 years.

[Roberta]

Some orchids actually bloom best when rootbound. Cymbidiums often bloom best just before they split the pot. Others, like Catts, may do best as they are climbing out of the pot. Some others, like Ansellia africana or Dendrobium speciosum may fill the pot and then send some roots upward (bird's nest roots) that in nature would collect detritus. So "tight shoes" work very well for many.

[Ray]

Considering that mounted plants, like those in nature, are never “root bound”, I believe the true measure is “mechanically stable and secure”. I agree with others that is does vary.

For example, I tend to put phals in large pots and repot them before they are anywhere close to being root bound, and they bloom happily.

[estación seca]

Perhaps most important, you can fit more orchids into your growing area if you use smaller pots.