If price is the primary consideration, there should be no reason you can't sub pumice for Turface. The most important considerations are the physical properties (geometry, porosity, size/mass) of the components/amendments. If you can find pumice in that 1/16 to 3/16 size range, I'm certain you'll be happy with it's utility and durability.

I use Turface in raised beds, but it only sets me back (got an invoice today for the last pallet) about $9/bag, delivered. I wouldn't hesitate to sub the pumice though.

Being so close to Oregon, you may be able to find "Axis" for the beds & "Play Ball" for the container soils at a lower price, too.

Al

I would add that in a container the size of lava rock is more important and the 1/16- to 3/16th of an inch is a great size. In garden beds the size can be bigger depending on if you are doing root crops. I used up to half inch size in raised beds and grew great squash, tomatoes, pumpkins etc. But carrots and onions etc. deserve the smaller sizing. Another thing to be mindful with lava rock is it is mined and then crushed but not washed or rinsed sometimes resulting in residual salts and or high PH. Thing to maybe test if using in quantity AKA cubic yards of material.
I miss Hawaii for the ease of access to cinder rock (lava rock). I grew some incredible stuff in containers and in the ground with it over the years. I am playing with a much smaller size available here in Texas as lavasand and it is alright but too many fines for my taste and for some uses that I would like it use it for.
Good Luck and Happy Growing David

Why either Turface or lava rock for growing roses?

Other than some rose societies and suppliers selling Turface advocating the use of Turface (1/3) as a soil amendment for growing roses, there are way more published findings about hydroponic and soilless roses grown in perlite, perlite mixed with coir or peat, or rockwool for either basic soilless culture research or small and large commercial operations than Turface. I periodically read about Turface used in research, but I haven't been able to find a rose study or a comparative study about the use of Turface for growing roses.

One commercial supplier for horticulture products reports that pumice is readily available and used in large scale by commercial rose growers in Isreal (desert climate and low altitude), but then I also find rose producers in that country using accepted coir or rockwool as substrates for growing roses commercially in some hybrid hydroponic operation to keep initial investment and greenhouse production risks down. There is at least one published rose study I read which suggested that ownrooted rose plants grown in perlite/coir mix had higher flower production than on pumice. Another study found that rose productivity significantly differed among flower stem classes (5) while different substrates tested did not have statistical significance.

The lack of data on Turface for growing roses (or floriculture) could also be it's not economical or commercially viable for small or large producers.

Thanks for the responses.

Al,
Did find a Play Ball retailer close by, so I'll try some. By volume it's only a little cheaper. It is less dense than Turface, which seems attractive. Although probably after watering it won't make much difference.

hitexplanter,
Good inputs for me. I'm actually just putting in ~10 gardening holes (not beds) in my sloped yard to grow squash, tomatoes, cukes, melons, root crops. The runaway rabbit population doesn't attack these plants. All the rabbit attracting plants, beans, lettuce,.... are in containers on a deck.
So lava rock looks attractive for the gound plantings.

Would just hosing the lava rocks down with a high pressure hose take care of any potential "residual salts and high pH issues"?

legacy,
I've read your trying hydroponics this year. It probably is the best method for the most production in the smallest space. Many years ago >10, I had a NFT homemade system. Had it for 2 years. After a 2 power outage killed everything, I switched to organic beds (in a previous house). Hydroponics was quite interesting to learn about, even attended a tradeshow for fun. But I can't be counted on for doing regular maintenance or watering so switched to systems more forgiving of neglect. Also I don't like the way perlite or rockwool looks, just a personal bias. One note is that at the tradeshow I attended, the local high school had a booth where they grew lettuce in a float system. In one container they used a complete chemical solution with micronutrients, in the other they used either an organic solution or a biodynamic one that had organic elements and chemical ones mixed (Earthjuice?). They gave out samples of each for tasting. The difference in taste was quite remarkable and unexpected. The "chemical" lettuce was crisp, watery, and comparatively tasteless. The organic/partially organic one was less watery and richly flavored. Partly due to that one taste test I switched to organic growing.

Cheers all

High pressure hose should deal with the salt residual problem if it exists but not likely to wash of enough to affect ph. Since your only doing small quanities relative to situation I wouldn't get too worked up about it after a quick wash. Might do a quick paper test (ph) from pharmacy just to see if it way out of wack then deal with it if needed. Other ways to test is to grow small crops and test results before wholesale committing to pumice. I always try to commit a small amount of plants for testing various media combos or fert changes as I like most on this forum are always looking a ways to improve performance or ease of growing or cost effective materials or .... Growing is fun and a challenge and that is why after 20 years I still feel like a kid in a candy store looking forward to the next piece of candy. I tried this and liked it but what about this one......hmmm.
Anyway stop by often and throw in your two cents we all learn from the sharing and look forward to hearing about your growing experiences.
Happy Growing David

Where in Northern California do you live?

You may wish to search for Turface (or Pro's Choice) at Lesco (now part of John Deere Landscapes.

Here is a link that might be useful: Northern California Turface or Pro's Choice

Hi,

Turface MVP:
-porosity (% air space)= 80
-water capacity % = 50
-saturation (water/porosity) = 60

Lava Rock:
-porosity (% air space)= 80
-water capacity % = 25
-saturation (water/porosity) = 31

If watering more often isn't an issue then lava rock is fine...

Here is a link that might be useful: Soil substrate comparisons

Contractors for NASA have looked into various root supports - for possible closed ecological systems for moon colonies and the like. They compared Turface-like products, Zeolites, and other materials. Anyway, the very first time that you water Turface is different than most other materials. Turface is fired clay - that means that it is pre-dried and full of microscopic pores just hungry for water. If you "dry" Turface at moderate temperatures and wet it a second time, less water is absorbed than the first time. Some of the water from the first watering is held very tightly in the microscopic pores of Turface and resists drying at moderate temperatures.

Your experiment looks at the bulk properties of soils. Consider polymers like soil moist in something like turface. The polymer granule swells with water; after draining the mix, the surface of the polymer granule is in contact with solid (turface) and pockets of air. On the other side of the surface of the polymer granule is nearly 100% water. In such a mix, on the scale of about a millimeter, you have drastic changes in composition from "100%" solid to 100% air to "100%" water.

When you consider stuff like Turface and Zeolite you need to look at the microscopic properties on the size scale of bacteria (1000 times smaller than the example above); and even smaller at the atomic level (yet another 1000 times smaller). You have pockets of air, water, and solid at these size levels in the case of Turface and Zeolite. Watered and drained Turface looks like a solid, but packed inside is lots of water and air.

Organic materials like bark or peat probably also have micro structured pockets of solid, water, and air.

To measure the microscopic pockets of water and air you need to do lots of experiments like the following.

1. Weigh soil mix
2. Water
3. Drain and weigh.
4. Evaporate at room temperature and weigh.
5. Evaporate at room temperature under partial vacuum and weigh.
6. Evaporate at room temperature under higher vacuum and weigh.
7. Repeat 2 - 6 several times.

Step 7 makes sure that drying under vacuum doesn't change the structure of the soil mix - ie., making it hydrophobic (water repellent).

------- the punch line ---------

If I recall correctly, exotic experiments like those listed above find that lava rock (scoria?) doesn't have the same type of microscopic water and air pockets that Turface and Zeolites have. Lava rock looks porous, but this is only at the visible size range, not at the micro size range.

---------- nanotechnology -------------

"Nanotech" is the next industrial revolution. Turface and Zeolite are nanotech potting materials; lava rock is not.

Axis is almost nanotech, but not quite. It has interesting porous properties at the bacterial size scale, but mundane at the atomic level. I don't really know where perlite and pumice fit in the nanotech to macrotech spectrum, but I suppose they are in between Axis and Lava Rock.

I would consider bark and peat to be nanotech.

Nothing that I wrote above should be considered to mean that Gojosan's experiment to be worthless. On the contrary, it was very useful.

The first time you water turface you can hear it sizzle, it gets slightly warm, and a tiny bit of dust wafts upward. Drain it, "dry" it, water it again and there is no sizzle, no temperature rise, and no dust storm.

Turface is sold in paper bags. When repackaged in plastic bags by Schulze and labeled as "Profile Clay Soil Conditioner", the retailer may leave it out in the rain in the outdoor garden section of the store. If the bag is leaky, it may be pre-watered and there is no sizzle the first time.

Note: Sizzler Steak House is a chain of restaurants in the USA.

Hi npthaskell,

I didn't do that experiment, just thought you'd find it useful. You point about micro-pores is interseting, another procduct which is used indoor is "grow rocks"...similar to turface but bigger in size and used in hydroponics.

On the topic of soil moist I would suggest you stay away from them:

I would be very careful before I used that. I do not use them as I've read the water crystals can actually "steal" (absorb) water from soil when they are dry and steal nutrients too...

Heres are a few quotes from the PDF I attached to this post. The PDF was written by Washington State extension educator and scientist, Linda Chalker-Scott. The title of the PDF is "Super-absorbent water crystals are they really so super?":

Quote 1:
"Moreover, excessive use of PAM can lead to nutrient deficiencies; phosphate and silicon were reduced in tomato and wheat, and this latter plant also suffered manganese and boron deficiencies when grown in under high PAM concentrations."

Quote 2:
"Summary and recommendations:

Many of the products labeled "water gel crystals" and "poly-clear" are cationic PAM gels. Not only are they are more toxic to aquatic organisms and generally less effective than anionic gels in landscape situations, they can also contain higher levels of residual acrylamide. Even though these cationic gels are banned for many applications, they are still manufactured and sold in the United States, China, and other countries. Cationic PAM hydrogels should not be used in gardens and landscapes.

It is difficult to predict short-term effectiveness of anionic PAM hydrogels on plant survival and establishment, since the ability to absorb water is reduced by several environmental factors, especially salt, temperature extremes, ultraviolet radiation, and microbial activity. The functional lifespan of cross-linked PAM hydrogels used outdoors can be as short as 18 months and at best only a few years; they cannot be regarded as long-term solutions to landscape water needs."

Quote 3:
"Even if gels are protected from environmental exposure they will still be broken down by decomposition. A number of naturally occurring soil microbes have been identified as active decomposers of both soluble and cross-linked polyacrylamide gels. Decomposers include bacterial species (Bacillus sphaericus and Acinetobacter spp.) and white rot fungi (Dichomitus squalens, Phanerochaete chrysosporium, and Pleurotus ostreatus). The fungal species solubilize the polymer, which is then susceptible to further degradation by many other soil microbes.

ItÂs not surprising that polyacrylamide is rapidly broken down by decomposers; one study found the average size of the polymer to be less than 25% of the original in only 14 days of microbial action. These gels contain a significant amount of nitrogen, which is often a limiting nutrient in both aerobic and anaerobic environments."

Quote 4: (a quote from the "Idaho Gardener")
"Basically, hydrogels also called polymers, or water saving crystals, are a big no no and if they arenÂt they should be. Contrary to popular belief, they do not make the water they absorb available to the plants which need the water, and worst of all, when they decompose they become nasty little toxic, hazardous pollutants in the garden and on the planet. Can you say "ICKY Yuck!?""

HTH :-)

Hi again,

Well it shouldn't be too big of a deal if turface MVP does't continually absorb/release the original amount of moister it first absorbed...turface isn't used for moisture retention per say, more so, it's used for air porosity %.

I attached one more PDF for you about why you should be carefull using hydrogells. I may suggest using rockwool "grow cubes" (1/2" by 1/2" by 1/2") instead of hydrogells for moisture retention. A big bonus with the grow cubes is they won't break down and fill in the little air spaces in the soil as the hydrogells will.

Thank you for links to hydrogels. I note that there have been threads in this forum about soil moist, but I haven't studied them yet. I was not advocating their use. My previous discussion of soil moist granules dealt with their physical properties - you could substitute "cubes of jello" for "soil moist", and my discussion would be even improved! By the way, I used the system "Turface - Air Pockets- Soil Moist". The argument is improved if I use "Granite Grit - Air Pockets - Cubes Of Jello", because granite is a solid while Turface only looks like a solid.

I have read your links. Note that Linda Chalker-Scott, the debunker of horticultural myths, seems to be focused on soil applications of hydrogels, not its potential utility in containers. When I tried soil moist in soil, repeated water drying cycles forced the bobs of gel to the soil surface, where it formed a slime. I gave up on its soil use because of its flotation, not because of any environmental concerns cited by our debunker.

I remain neutral on its use in containers; I have no position.

> turface isn't used for moisture retention per say

Given that turface is microporous, once mix is drained, and then mildly "air dried", the surface of turface looks dry (but still has a glossy sheen), but is full of moisture inside. There is a first pool of internal water that can supply roots with a thin film of water. Upon further mild air drying, it looses its "sheen", but there is still a second pool of internal water that could maintain a high humidity around the roots. Once the second internal pool water dries out, a third pool of internal moisture is only extracted by vacuum or mild heat (but this third pool of internal moisture doesn't doesn't do the roots any good, LOL!). A fourth internal pool (also useless to roots) is removed only by kiln drying. Anyway, this is my interpretation of what I read on websites from the NASA researchers and the manufacturers of Turface-equivalents. Upon my retelling of the story, I hope the story isn't mutated too much.

If I recall correctly, once granite grit drains and air dries, that is it, there is no internal moisture pool that is of any use. If I recall correctly, lava rock would behave like granite.

Hence Turface would be perfect for plants like orchards, whose roots only want transient exposure to liquid water, but loves long exposure to high humidity.

I've been thinking of lava rock as being equivalent to granite grit. Upon further reflection, this isn't exactly true

Once a mix with lava rock drains, the lava rock's pits in the upper surface retain little "tide pools"; ie., pockets of water far above Al's "perched water table". Granite isn't nearly as pitted, so there very rarely any "tide pools" on its upper surface. On the bottom surface, gravity would drain out any pores, so there are no tide pools. To drain the upper tide pools, you would have to flip the pot upside down. (James Bond: "I want my pot shaken, not just wicked", LOL.) The bottom surface of lava rock would dry quickly, with no internal reservoir, just like granite.

Punchline 1: Lava Rock should retain a little more water than granite.

Punchline 2. I don't think that Lava Rock (which is so highly variable from rock to rock) has enough pits on its upper surface to form enough tide pools to compete with the internal pores of Turface.

I've been thinking of lava rock as being equivalent to granite grit. Upon further reflection, this isn't exactly true.

Granite grit is relatively smooth compared to lava rock. A piece of bark, coming in contact with a piece of granite grit, could have have an extended contact surface that is relatively tight. The contact surface may have micro spaces about 1/100 to 1/10 of a millimeter, or about 10 to 100 times the size of a bacterium, or just at the size limit of human vision. Lava rock is rougher. An extended contact surface with a piece of bark could have mini spaces in a size range of 1/10 to 1 millimeter; ie., barely above (to fully within) the limit of human vision. Turface is about as smooth as granite; so micropores in an extended contact zone between bark would be about the same size as with granite. But since granite grit sometimes has angular ridges while turface is globular, any extended contact zones between bark and turface could be larger than extended contact zones between bark and granite. An extended contact zone could mean that the internal water reservoir of a turface granule (at the pseudo-dry but glossy stage) would flow into the bark (and vice versa). While I don't believe that lava rock has an internal water reservoir per se, an extended contact zone above a tide pool (a pit on the upper surface of a lava rock) would as a mini reservoir, while an extended contact zone below a pit (on the underside of a lava rock) could act as an oxygen reservoir.

------- disclaimer --------

I have observed none of this under a microscope, nor read any soil text relating to this. I am just using logic based on my memory of my naked eye observations of turface, lava rock, chicken grit and bark.

------ punch line -------

If my logic is correct, how does all of this effect drainage, the medium and long term storage of water and oxygen after drainage, and the wicking of water and oxygen reservoirs to roots in the medium to long time frames? I have no real idea, but it is fun to think about. I speculate that the mini (1/10 to 1 millimeter) water and oxygen reservoirs in the contact zone between bark and lava rock wins in the short to medium term (about 1 day after drainage). I speculate that the micro (1/100 to 1/10 millimeter) reservoirs in the contact zone between bark and turface wins in the long term (a few days after drainage). In the system bark and granite grit, grit is just a spacer that creates macro pores (about 1-2 mm) of oxygen, not having any real function as a water reservoir.

I love this thread!!!

Npthaskell said: "Axis is almost nanotech, but not quite. It has interesting porous properties at the bacterial size scale, but mundane at the atomic level."

Sounds about right. However, I believe this is Axis' claim to fame in the sense that the company markets these larger (and more abundant) sized pores as being able to hold more water, and more importantly make that water available to the plant's roots.

I'm thinking of it in this manner: To an extent all of these materials are only able to release their water to plant roots above a certain saturation percentage. If Axis' statements are true then it would be more effective at releasing it's stored water to plant roots since it can release it's water at a LOWER saturation percentage than Turface.

Again, according to their website this all sounds feasible. I'm currently using Axis in place of Turface in a few applications. Thus far, the results are promising though it's way too early to tell if I can consider it better than Turface.

I'm assuming that the information presented on EnviroTech's website concerning Axis' properties is correct. If I go strictly by the numbers, then Axis is superior to Turface in nearly every way. I have no way of proving that yet, but one of my favorite qualities is its weight. Axis is much lighter than Turface. Though I can't cite any notations concerning this as an advantage, in my mind I feel as though root penetration and ramification would be easier through a material that weighs less than another.

My paragraphs are starting to sound like an advertisement for Axis and that I think it is the "be all, end all" of soil amendments. This was not my intention :) I just enjoy these subjects so much that I have a tendancy to ramble.

You also said: "To measure the microscopic pockets of water and air you need to do lots of experiments like the following."

I'm attaching a link to a discussion in the Cacti & Succulents forum dealing with this particular subject. The experiment was conducted by Xerophyte. For those of you that don't know him, think of him as "The Al of the Cacti World". He really knows his stuff!

Though his experiment isn't near as technical as the one you outlined, it still has great merit in regards to comparing porosity and saturation of various materials we use. Check it out. (I may have linked this experiment in another recent thread, if so I apologize for my redundancy).

Zeckron wrote:

> The experiment was conducted by Xerophyte

Previously in this thread, Gojosan linked to Xerophyte's experiments, and quoted from them. Because Gojosan quoted Xerophyte, I was confused, thinking them to be one and the same person. I responded to Gojosan thinking that he was Xerophyte. Oops!

Zeckron wrote:

> If Axis' statements are true then it would be more effective
> at releasing it's stored water to plant roots since it can release
> it's water at a LOWER saturation percentage than Turface.

That is my memory of my interpretation of everything I have read about the subject. In terms of a sponge and source of water, I think that Axis also wins over Zeolite.

In terms as a cation exchanger (ie., a sponge and source of ammonium, potassium, calcium, magnesium, and resisting acidification), Zeolite and Turface win over Axis.

I wrote:

> In terms as a cation exchanger....
> Zeolite and Turface win over Axis.

Some consider this to be too much of a good thing. Zeolite and Turface may sponge up some nutrients too tightly. For example, one seller of a mix of Zeolite with a little bit of fertilizer, recommends adding Zeolite to a level of 10% to 20% of the mix. When Turface is added to turf soil, it may need a little extra ammonium fertilizer, otherwise the grass yellows.

----- Punchline ------

Perhaps the best possible solution is to dilute either Zeolite or Turface with some Axis to optimize the average cation exchange capacity of the final mix.

hey,

I spoke with the Axis people and here's the low down:

Axis will absorb 114% of it's weight in water and has a 90% water release rate with a very low tension level (eg. it's very easy for the plants to extract up to 90% of the water held within Axis, this is due to the average pore size of 1 micron.) Axis also has a very good CEC level of 27 meq /100 g...all this with an air porosity rate of 27% and a water porosity of 26%!!!

Turface on other hand will absorb around 55% it's weight in water and has a very low water release rate of around 5% and a high tension level due to the very small pore size of turface. I believe (but not sure) that the CEC of Turface is worse than that of Axis.

Zeckron,

How does Axis regular compaire to turface, peat, etc in regards to moisture retention in container? I ask because I like in a semi-arid environment and I want to have my substrate retain as much moisture for as long as it can while keeping the air-porosity level above 20% (my plants are non-fleshy roots).

Heres one mix I'm going to play with:

5 part Axis
2 part bark
1 part peat

Gojosan, I haven't had my Axis for very long yet. However, as I mention in the "Axis Info vs Turface" thread it seems to be superior in every way. However, I haven't been able to make a long term or very detailed analysis of it yet. After all, I've only had it for less than 2 months or so.

But so far, I'm very pleased. I'm definitely no scientist, but Axis seems very promising albeit a little pricey.

Availability nationwide is a major problem right now. But due to it's success, the company is growing very rapidly and adding new distributors/retailers all the time (as per David from Envirotech).

I believe it's moisture retention is inferior to peat (as are most amendments). But it doesn't break down, retains it's shape, and supposedly won't cause big swings in pH.... Essentially everything you love about Turface but taken to the next level.

I hear you on wanting to maintain a semi-arid mix. Most of my containers are succulents, so keeping things from getting water-logged is very important. Turface and Axis do that very well.

I agree with zekron: this is a great thread! I've just gotten a couple of bags of Turface All-Sports from John Deere Landscapes (supposedly the same as Turface MVP, but to my eye All-Sports is a bit smaller), and was puzzling about how/when to use it in my hydroculture pots instead of the extremely different LECA I've been using so far. I'm still not up to speed on using Turface in containers, and now there's this new player, Axis! I seem to be in the wrong part of the country for Axis, but on zekron's recommendation in another thread I called our local Napa store and they do have Napa Super Absorbent part #8822 in stock ($7/25 lbs., so a bit more expensive than in zekron's area, and also by weight somewhat more expensive than the Turface, which was $10/50 lbs.; however, I don't have to spend $15 in gas to drive to my Napa store (unlike John Deere), and I'm hoping that the Axis substitute is lighter than the Turface).

Although I'm a little shaky on this stuff once you get down to the subatomic levels being discussed here, it does sound like the Turface/"Axis" mix might be a good idea (assuming Napa's product is equivalent to Axis, I'm going to give it a go, anyways!). I'm also thinking of adding some superabsorbent crystals to these containers. I've used a perlite/superabsorbent crystal mix in containers before, and I do think the crystals have helped; plants that grow their roots into a crystal seem to be especially happy. However, I've also had npthaskell's experience in the garden, where lots of the crystals float to the top, making for a less than pleasant surface. On the third hand, though, I've pulled up some very happy weeds that have rooted through some crystals. So it's only the "unattached" crystals that float, not that I can see a practical use for that information!

So I'm curious. How do you monitor/maintain suitable water levels in pure Turface/Axis containers? I potted up a "snowflake bush" (can't remember the right name; a euphorb relative) in a glass jar (a la Waterroots), but even then I can't exactly tell where the water level is!
Cheers,

Alan

TTT