How do we acidify inorganic Bonsai soil?

Hello all..

I decided this year, after seeing the results myself, to switch over to an entirely inorganic medium for my trees, I use specifically Turface and have found that ALL the trees I potted into straight Turface have out-performed my other trees with various organic components in their soils. The difference is not subtle..Its profound and I have finally come to the conclusion that its "best practice" horticulturally at least for my trees and situation.

Looking to the future for species such as Azalea of even Trident maples that might prefer to be a bit on the Acidic side (or equally true for those wanting to be more on the alkaline side) how do we alter the PH of inorganic soils? Turface is of course PH neutral (tested it myself)

Do we add chopped long strand sphagnum? just a guess.. but Id love to here the opinions of the experts here

Thank you in advance for you time answering
-Jay

Miracle Grow makes a fert. for acid loving plants, I would just use that. For alkaline loving plants, I don't know.

You Know Billy I had that same thought about just "faking it" with a dose of Mir-acid once a month. But I'm really hoping to figure out a way to effect ph on a more (permanent) basis with the inorganics ..Making it more Alkaline is not so much a concern, I have found trees that prefer an alkaline soil PH are more forgiving of going towards the neutral side than those species that DEMAND acidity.

we think alike though.
-Jay

Using fertilizer for acidophil plants is not faking : when roots absorb the nitrogen under the form NH4+, they release H+ and the water around the root really becomes acid and this what matters. Organic ferts also acidify the substrate. Alternatively, if you have hard water, you can adjust its pH with an acid (nitric acid being the best) before you water. But if you don't get problem in the way you already practice, why change ?

Thank you for the informative response Alain.

Currently I am not growing an Acidophilic trees in my pure Turface, But I will in future once a few field grown Azaleas are ready, and was inquiring as to my future needs regarding these species. Its definitely interesting to finally find out exactly what happens in the soil when a product like Mir-Acid is applied, I always wondered what actually MADE it acidify.. That was a very helpful and interesting chemistry lesson..

took me back to my early days as a Biology major..
thank you
-Jay

Well, I am certainly no biology major, nor minor for that matter. I do, however, grow most of my trees in turface, largely due to a conversation I had with Boon several years ago.
Recently I had a problem with underfed bougies, so I began a regimen of liquid-only chemical ferts that I had on hand. Miracid is one. I used it full strength about every other day, largely due to the inability of turface to hold anything. It all drains right through, as it should. A problem with azaleas is their need for a bit more moisture than some other trees. I succumbed to the internal pressure and added a bit of organics to the soil mix for my azaleas, and they have responded quite well. But I think the most important change is the frequent watering with fertilizer mixed in. I also add micronutrients much more frequently than if in the ground for the same reason. It all just runs through the turface. The bougies that were starving are flourishing as a result. Hope this helps.

I think I read somewhere ..way back when..that the Turface granules THEMSELVES can hold something like 3 or 4 times their own weight in water, don't quote me on that, but when I have transplanted a tree in pure dry Turface, then lifted it into position up onto my deck, then watered, even after all excess has drained, man does that tree get heavy and stay heavy.

Also I use seaweed and fish emulsion combo and I've noticed during an emergency re-pot after a thunderstorm blew over a Wiegela, the odor of my Turface was like fine earthy humus due to the decomposition of my fish emulsion absorbed by the Turface. I believe the calcined clay granules themselves hold on to a shocking amount of liquid and I've seen how wet they will stay in deep grow boxes down below the dry looking surface layer...My only Idea for Azaleas was chopping up some long strand sphagnum and mixing it say 50/50 with the turface. As per Harry Harrisons recommendation. BTW the fines from sifted Turface make the best Mame soil I've ever used and maybe at this point I should say I actually Use something called Profield MVP conditioner which is a calcined clay that to me is kissing cousins if not Identical to Turface.

Either way I love the stuff and the results are just outstanding, the rot resistance and inhibition of inorganics are also very attractive features for susceptible species like Maples and Azalea...Lost a few to Verticillium earlier this spring and it was that experience that got me rethinking my soil mixture!

Add a little cottonseed meal. Cheap and will acidify the soil, also building up natural microbial fauna.

Interesting discussion, thanks everyone for sharing. I don't have anything to add about the acidification, but:

drgonzo wrote:I think I read somewhere ..way back when..that the Turface granules THEMSELVES can hold something like 3 or 4 times their own weight in water, don't quote me on that, but when I have transplanted a tree in pure dry Turface, then lifted it into position up onto my deck, then watered, even after all excess has drained, man does that tree get heavy and stay heavy.

I know you said not to quote you but in case anyone wants some numbers (I've been doing some soil component comparisons prompted by a discussion on another forum): I put 1/2 cup of dry turface in a pot and watered thoroughly...after draining I shook out as much excess water as I could. Before watering the turface weighed in at 70 g; immediately after it weighed 119 g...so the 1/2 cup of turface held 49 g of water...about 70% of its dry weight. Not 3-4 times, but still pretty impressive. Unfortunately I don't really have the equipment to do this measurement for individual turface particles.

Chris

hi,
i include shredded live sphagnum moss in all my mixes (akadama, kirynu, kanuma, grit etc) and 2 or 3 times per growing season i submerge the entire pot in a bath of miracle acid mixed at 3 caps full to 4 gallons of water (imperial gallon). I find the full soaking method to maintain a good soil ph works really well, as it does under the trunks properly, something watering from above doesnt always. I do the first bath early season once the spring rains have passed, once in mid summer, and once mid autumn. This sorts the soil out after spring rains that leach these types of soils out at a very important 'wake up' time in the trees life, then the 2nd bath balances all the hose pipe watering of summer, while the final bath readies the tree for winter although this 3rd treatment is not necessary on all trees.

in between this i use rapeseed feed cakes that i make and these include kelp, epsom salts, full trace elements and sulphate of iron. This combo, with a blood fish and bone treatment mid season is giving me very good results with the inorganic soil mixes.

i find these soils make life in a pot easy for a tree, but feeding is far more critical for long term health and development. Underfeeding or incorrect feeding results in trees weakening quite quickly and losing their colour - especially in the 3rd year and beyond in the same soil.

I see some trees doing really well in cat litter type soils in the first 12-18 months but then losing vigour - i think this is due to lack of things like trace elements as there is no organic breakdown within the soil, so it becomes essential to add these annually.

Chris

Thank you for that little test I always wondered how much the stuff actually was absorbing 70 % is very impressive and I have actually still had trees suffer overwatering even in straight Turface. I'll tell ya when you fill a 2 ft by 2ft by 10 inch deep grow box with dry turface, then water it in, then attempt to move the tree, you quickly realize you just made a procedural error!

I think I might have been thinking of Oil-dri when I said 3-4 times but I don't remember -middle age is when the memory truly begins to fail I have found.
-Jay

Thanks for the tips Marcus.

You know I had the same experience with inorganic soil loosing nutrients and I found that when I switched over to purely organic liquid feed (fish and seaweed emulsion) they came right back. And even the dry turface when moistened will have an organic smell to me, no doubt from holding on to the residual fertilizer. So organic fert with inorganic soil so far has been the magic combo up my way too.

coh wrote:
I know you said not to quote you but in case anyone wants some numbers (I've been doing some soil component comparisons prompted by a discussion on another forum): I put 1/2 cup of dry turface in a pot and watered thoroughly...after draining I shook out as much excess water as I could. Before watering the turface weighed in at 70 g; immediately after it weighed 119 g...so the 1/2 cup of turface held 49 g of water...about 70% of its dry weight.

Interesting numbers, but could you give your results as a ratio volume/volume because what matters is finally the volume of water retained in the pot, independently of the specific density of the substrate ?

TIA

1/2 cup = ca. 114mL, so 114mL turface held 70 mL water. This gives a ratio of 0.61 water/turface, volume to volume.
Oliver Muscio

so a little more than half its volume in water is that what that indicates? I don't do Math so someone has to help.

You might say it holds an amount of water between half and two thirds (61%) its volume.
Oliver

WOW!

That gives me serious food for thought with regards to my watering schedule.

thats a surprising amount of water, but that does confirm a little more objectively some things I've observed with regards to Turface and its water retention ability.

If you really want to know where you are starting, for very little money you can submit soil (or 'growing medium') samples to your county extension agency for a 'soil analysis'...you will get pH, CEC, etc.

Oliver Muscio wrote:1/2 cup = ca. 114mL, so 114mL turface held 70 mL water. This gives a ratio of 0.61 water/turface, volume to volume.
Oliver Muscio

Ah, sorry of being this dumb. I didn't notice that "cup" was a precisely defined measure. That is definitely very very high !

Ah, well, in the US we are still using teaspoons, tablespoons, cups, pints, quarts and gallons, fluid ounces and pounds. As a chemist, I am bilingual with the metric system.
Oliver

Its an amazing amount of water, I walked my trees this morning looking at those in Turface and seeing the top inch dry, I said to myself 'skip it- there's a lot more water in their than I think'..(these are grow box trees by the way)

drgonzo wrote:WOW!

That gives me serious food for thought with regards to my watering schedule.

thats a surprising amount of water, but that does confirm a little more objectively some things I've observed with regards to Turface and its water retention ability.

Any chance you'd be interested in further describing your observations?

I've only got 1 decent sized plant (a chinese quince) in a primarily turface soil mix. It's been a learning experience figuring out how much to water. I haven't really been able to go by the weight of the pot, as it feels almost the same (heavy!) when the plant is wilting as when I've just watered it. This is a plant that was just "collected" this spring, so I'm not sure how well developed the root system is (though there are roots growing through the drainage holes).

Chris

hi,
when you're measuring the water retention how long are you waiting before recording measurements?

it would be interesting for a set of measurements to be taken at 1 hour intervals - then we'd have a bit of a picture of how much water slowly drains out and how much is retained. we'll have to ignore back ground humidity and anbient temperature though. - and in the UK what name does this product go by?

cheers

Jay, interesting thread. My sensei here told me to use Alum Sulfate, sprinkled on the topsoil. How much? He said like "heavy salt" on a dinner plate. But check pH first. Apply 1x/mos. This is using 100% Turface.

But it seems adding chopped up sphagnum in small quantities to Turface seems promising for healthier root growth. I'm already experimenting using 100% Turface, and 2:Turface, 1: grit and 1:lava (which I only have a little) for my inorganics. I need to get a baseline before I try anything new

Uh, this is a little (i.e., a lot) late, but I just realized my previous calculation of the volume of water retained by turface was based on my misreading of a previous post. The 114 mL of turface had an initial weight of 70 grams, and retained 49 grams (= 49 mL) of water. So, the vol/vol ratio of water to turface should have been 49 mL/114 mL = 0.43. Given the possible errors in the measurements, I think one could say the turface retains somewhere between a third and half its volume of water.
Oliver