I've grown Phalaenopsis orchids in gritty mix and they did very well. Mine all bloomed within six months after transplanting from regular mix to gritty mix. They still need regular fertilization and high humidity to do well. I don't know what kind of orchids need root pruning, but I wouldn't root prune a phalaenopsis.

Hi
have used it on terrestrials and hardy types but grow most of the epiphytes mounted or in crushed lava rock
What type are you growing?? gary

My personal preference is to use a bark-based mix with red lava rock and perlite....but I only grow Cattleya type orchids.

Josh

Hello All -

Thanks for the replies everyone.

I am growing mostly phalaenopsis orchids that have come from the big box stores.

I also have a couple from a nearby botannical gardens -
The ones from the gardens are:

D. woo leng
issaku nmagata 'emi'

As far as root pruning I was just thinking of cutting off the roots that are visibly brown instead of a healthy looking green. Some roots are brown and so I assume completely dead. So perhaps a root 'trim' is a better term?

I read on a website somewhere that for phalaenopsis you should root prune/trim once per year.

Thanks,
Brian

Sometimes I buy the Phalenopsis from Trader Joes, but mostly I have them given to me by friends when the bloom is through. If they have not cut off the old stem, in most cases, new stems grow off the old stems. One has been blooming for almost a year on successive stems, most off the the original stem. When gifted with a bloomed out orchid, I repot into fir bark, trimming off any brown roots. I will soak the new pot overnight in water to hydrate the bark thoroughly, then water only as needed. In a month or two I will soak again for a few minutes in a fertilizer solution. I feel sure gritty would work about as well, but I don't bother. Al

The very coarse bark mixes are really hard to overwater.. even harder than gritty mix.

I haven't used gritty mix persay, but did use coarse diatomaceous earth as a single component potting medium. The phals grew *quickly*, like they do in sphagnum, presumably because a large surface area of root contacting the medium. However, I did get some root rot. The bark mediums are more forgiving of both underwatering and overwatering, and more practical for day to day care.

The problem with the diatomaceous earth, and i suspect with the turface as well, is that if you allow it to get really dry, it dessicates/kills the roots where they contact the medium - because they're so absorbent. I wrongly assumed I couldn't overwater because of the coarse inorganic medium.. but I was wrong.
Perhaps the other two components will balance this out. Overall though, I don't think there's enough air in the gritty mix for a mature phal.
Sorry for rambling.