Pterostylis curta aerial root

[Herrania]

I'm trying out growing Pterostylis curta, and am curious about the roots it's putting out. I was somewhat expecting that I might have some out of the bottom of the pot, but now I have one exposed at the top.

Is this a sign of too much water? Also the spots; this window occasionally gives odd sunburn spots, or are these something else?

[Roberta]

I have found that these just do what they want to do. I have had growths climb up the edge of the pot, roots somewhat exposed, and those "escaped" growths bloom anyway. At this time of year, just keep it well watered. That does look like a bit of sunburn... or maybe something nibbling on it. I do grow these rather shady. Also, what are your temperatures? Cool (like near the window) is fine. (I'm fortunate in being able to grow them outside... not an option where you live!)

Thinking ahead a bit... when it goes dormant (you'll see leaves looking ratty somewhere around March-ish) you'll be cutting back water. When the leaves die back (somewhere around April) put it where it won't get watered. In mid July, I repot... dump it out on newspaper, put on your reading glasses because tubers can range in size from a B-B to a marble, the former are hard to see but they can still grow just fine. You will very likely have more than you started with, they multiply like rabbits. Along with looking to see what has grown, you will want to repot because the tubers tend to work their way to the bottom of the pot, if you don't repot they'll start growing out of the holes.

[Herrania]

Thanks; temps are currently 65-75. I wish I could grow these and many more outside, there's a long list of stuff where I'm just a tad too cold/wet in the winter or too hot/dry in the summer.

Thanks for the tip on repotting, I was going to add some pumice to the mix next time but now it seems like it will be a pain. Is there much need to get them planted back in absolute perfect orientation?

[Roberta]

I use cactus mix potting soil, then add some sand, pumice, and perlite, so that I have about 50% inorganic, and it is well-drained. So when you unpot, that would be a good time to amend the mix. If they're still few enough to fit into the same pot, you don't need to use new soil, but once they start to multiply you'll do that... save the old in case you missed any.


If they are still completely dormant when you repot, the orientation isn't important at all. If you find that they have started to sprout, the growth should point upward (the leaves develop before the roots) but if they go sideways they'll straighten out. I don't think that I have ever found them starting to wake up in mid-July. At beginning of August, I once found that they were already starting to sprout...depends on the weather.

[Herrania]

Excellent, I've been working on an Oeceoclades mix that fits that. Any need to include marble chips or something acidic, etc?

[Roberta]

No need for anything special. My mix varies from year to year because I don't measure, just dump things in until I have a loose, open soil. I find this species to be the absolute easiest (at least under my conditions) of the terrestrials to grow. I have struggled with other Pterostylis species (still trying), this one just keeps growing and multiplying.

Here is a link to a little culture sheet that I wrote - on the San Diego County Orchid Society website.
https://sdorchids.com/culture_docs/P...lture%20RF.pdf
It was written with my southern California climate in mind, but I think that you can extrapolate to your environment.

[DirtyCoconuts]

Hey Roberta. Have you written any other care sheets like that? Can I download them? I find your instructions easier to follow than any other expert I’ve found.

[Roberta]

Glad you like it! I haven't done any other care sheets like that, I have some notes on the European and Australian terrestrials scattered around (I think somewhere on the OB even), the best reference for those is in the Orchid Digest (April–June 2019). "Growing Mediterranean Native Orchids: Serapias, Ophrys, and Orchis—An Interview with Scott McGregor". Orchid Digest. 83 (2). By the way, a publication well worth subscribing to. These temperate-zone terrestrials are just so different from the tropical epiphytes that everyone grows, they need their own "documentation".