I have seen questions regarding the use of pumice (mine is gray) in place of perlite in the gritty mix for containers, but not found any replies. Hence this post.
Pumice is a good replacement for perlite, but there is no perlite in the standard gritty mix. Are you thinking of the 5-1-1 mix? In the gritty mix you may be able to use it as a replacement for granite, but it does hold significantly more water so you'd probably want to use more of it. Something like a 4:3:2 ratio of pumice:bark:Turface. I use this ratio when replacing the granite with perlite, but pumice should be similar.
For me, pumice holds a lot more water than you think.
I use it in place of 'turface' or peat.
Thanks for the responses -- much appreciated! So, if I use pumice rather than turface (which I would much prefer!), what would the recipe for the gritty mix be?
What is your goal here? Are you trying to find a use for some excess pumice, or are you having a hard time locating Turface?
If it helps any, I did a comparison test where I found that pumice held about the same amount of water as lava rock and just slightly less than perlite. As I said above, I use perlite as a substitute for granite. Since pumice holds no more water than perlite, I think you'd have some trouble using it as a replacement for Turface. I know some people grow succulents in straight pumice, but those are more drought tolerant plants and I believe they're watered pretty frequently. You could try substituting pumice for Turface on a couple pots, but I'd probably use little to no granite and be prepared to add some Turface if you find yourself having to water too often.
I am still trying to find a local source for Turface, and also am not too keen on the waste involved with screening, as has been reported in a few posts at GW. So pumice would hopefully make a good alternative, and there are a number of local places that carry it.
I will be using the gritty mix almost exclusively for dwarf conifers.
More porous pumice holds more water than granite chips. Two grit items that aren't going to break down very quickly. Neither of them are as flexible or soft like perlite and turface are.
Shipping moving and handling, both will have a small amount of finer to powdery spreading more downward in any bag barley any in comparison to the perlite and turface and would still need a rinse.
Both granite chips or pumice in a mix are easier to water flush if needed, also very easy and fast to 911 re-pot
Slight disadvantages to pumice and granite: Pot tipping is sill allowed by winds or accident. Roots both hard materials could become more difficult for a conifers smaller growing roots to move freely in a container.
If I'm backwards:
Roots growing in either granite or pumice materials as part of a gritty mix container it's harder for younger roots to move these materials.
If I'm still backwards:
During growth keep an eye on the base of the plant as harder grit materials may also pinch the plant at the base line of pot and soil. If pumice and/or granite in a mix can restrict or pinch the base of a growing conifer than it can do the same to it's growing roots.
I have most of my succulents in straight pumice or a pumice/bark combo (due to laziness about tracking down granite and Turface, and pumice's easy availability in my area) and I water once a week (or twice if it's really hot). I sift for fines and larger pieces so the remaining material is small but not fine enough to hold perched water. My plants do fine, even in my arid Zone 10. (I have some lilies and gingers in a bark/pumice combo with extra bark and they also do fine with a weekly watering.)
Maybe calcined DE would be a better sub for Turface. Try NAPA's part #8822. If we knew where you live, we might be able to help you find Turface. You might consider adding something to your user ID - like my 'z5b-6a mid-MI', or a large city we'd recognize that you live near.
Hi Al. I added my zone and location awhile ago, but it is not showing up on my older posts.
Laura suggested Napa 8822, and their store in Santa Fe carries it, so I am good to go!
Albuquerque, Mesquite, Las Cruses, and
20 Bisbee Ct.
all have Turface. If any of the first 3 are closer than Santa Fe, let me know.
Thanks, Al, but I am not certain that the Santa Fe outfit will sell to off-the-street customers -- they never responded to my email enquiries.
So... will Napa 8822 work as well, in the same 1:1:1 proportion?
If you can find the Turface, that would be better..
I like the Turface but the Napa #8822 is a good sub..
Lots of GWers use Ewing as a source for Turface, so I'm pretty sure they'll sell to you - worth a phone call.
In some states that aren't as dry as NM, it's better to use something like
4 #2 grit
3 screened bark
2 screened 8822 DE
but Laura's probably right, in that a 1:1:1 mix might be better for you because of the extra water retention afforded by the calcined DE over Turface.