So just what ARE you growing in? What did you end up with as a mix? Is it 50/50 Turface + vermiculite? Or - how big are the bark pieces you used?

Al

That wasn't very clear, was it. Sorry about that. Most of my plants are in 1/3 coarse pine bark, 1/3-1/2 turface and remainder vermiculite. Some are in 50/50 (eyeballed) turface & vermiculite. Most were switched over from peat-based mixes and all seem to have benefited so far, except for my Philodendron bipinnatifidum, which is rotting despite (or because?) of using much mulch over top of the mix for purposes of keeping toddlers from grabbing handfuls of mix and dropping it on the floor (easier to clean up). None have been in any new mix for more than a few weeks.

Ellie

Thought I should add that most of my houseplants go outside for the summer. I'm afraid the rains, while helpful in flushing salts (especially lately with the flash floods, not that they've accumulated much yet though), are keeping the vermiculite heavy mix WAY too wet. I have been poking them and even a week after the last rain or fertigation some of the slightly overpotted (it's what I had) are are still quite moist a couple-few inches down.

Ellie

Also, being the forgetful sort that I am, waited till now to remember that all these are UNsifted. I justified it by telling myself with 30-odd container plants, 2 kids and a huge new garden I didn't have the time to make a screen and do all the sifting, but I can shift the justification to the health of my plants if it makes a great deal of difference.

Thank you,
Ellie

Ok - if the pine bark is considerably larger in particle size than the Turface and vermiculite, it's almost like it's not there. The soil will retain virtually the same drainage characteristics as the Turface/vermiculite mix at 50/50, which means that it is extremely water retentive. How many plants are in that soil? We need to figure something out temporarily until you can get them out of that soil and into something better. It's pretty certain that you'll be continually fighting the soil they're in now for control of your plant's vitality.

Al

I have around 30-ish plants in that soil. Thanks for clarifying this, Al.. I was afraid of that. I guess the Landscape Supply people will be seeing a lot more of me as I pop in to buy more bags of Turface and dump the current in the garden beds. I will get a babysitter so I can repot within the next few days - again. :)

Speaking of which, I'm pretty sure I can get grit. I'm pretty sure I can't get small particle pine bark or any other bark locally, so I guess I'm doomed to add vinegar. Using your experience and judgement, what would be a good general purpose tropical foliage mix (ratio) of turface to grit? I can adjust from there I think.

Thanks,
Ellie

I won't advise you - directly - on a ratio as I grow houseplants in hydroculture and they are indoors all the time.

I can tell you though that I have used 75% Turface/25% bark as well as 50-50 turface-bark and in both cases it has been more water retentive than I personally wanted and I am not a guy who enjoys watering daily. (outdoor plants)

The only exception is that I have some sempervivum in a shallow (1.5" deep) and 12" diameter pot and there the 75-25 mix dries down nicely in a day or two, mostly because the width and shallowness allow for good evaporation.

I have youngish citrus trees in the 50-50 (Turface-bark) and it holds too much water. I put a couple in the gritty mix and am much happier with the rate it dries down although in the spring with 70F day temps and breezy it still takes 3-4 days at least.

Now that I think about it, I do have a fern in a hanging basket (indoors) that I potted in 50-50 bark-turface and I like it (I water it maybe every 4-5 days). It's a larger fern in an 8" basket.

I am probably not helping much, am I?

I will through out anywhere from 75-25 grit-turface for succulents to 75-25 turface-grit for plants that use water more quickly than others and 50-50 for the 'average' plant.

Keep in mind Al has a lot more experience that I with the houseplants though so I will be interested in his response.

I think you would be in pretty good shape with 50/50 Turface/grower size grit. You could probably do just fine with 100% Turface, too - if you screen it through insect screening. If you go the 50/50 route, make sure you're diligent about fertilizing. Every week at 1/2 strength when the plant is growing robustly, every other week when growth has slowed due to light levels or temperatures, and once per month during winter when the plant is taking a break.

Add a tbsp of gypsum per gallon of soil and include 1/4 tsp of Epsom salts in the fertilizer solution each time you fertilize. I don't think you'll need vinegar, btw. If, when using the fertilizer schedule I mentioned, the plants show yellowing you feel is nutritionally related, try the vinegar then. The yellowing COULD be symptoms of a pH induced Fe/Mn deficiency, but it's not something you should anticipate.

Al

Thank you all for your input, Al & justaguy2. I very much appreciate it and will definitely be repotting. I am also interested in hydroculture. I've had plants in that before and they did great, but I thought it was fairly ugly (hydroton), especially for small plants, and VERY expensive. The turface is at least half that. Is it unsuited for hydro for some reason? It is at least made of the same stuff.

The only problem with Turface in hydroculture is that it is a pretty small particle size so it displaces a lot of water that would be present between the larger hydroton pieces.

I do know of at least one person who uses Turface or similar for outdoor hydroculture. He claims it works fine even for tomatos, but I haven't actually seen any of his plants.

For indoor plants I can't think of any reason not to try it if you are so inclined. In fact if you try it you might prefer Napa Auto Stores product called Floor Dry. It's calcined DE instead of clay, but when wet it is a very attractive (I think) multi color material (all earth tones).

What! You don't like wet Turface orange?!

Al

I have no prejudice against Turface orange, but the multicolor of wet Floor Dry is hard to beat ;)

I asked the NAPA closest to me what their Floor Dry was made of and he said "clay" and that it was white. He didn't sound like he was sure though, since he added "...I think" after that. Any consensus on the different colors being specific materials? I guess I could buy a bag. Already bought one from Sams hoping it was good, but the freezer test mushed it.

Nevermind that, I called one a little further away with the same question and the lady that answered seemed experienced with it and said that it turns into paste when used. Definitely not using that.

You called a Napa store and they said Floor Dry turned to paste when wet?

I know many have had problems with the various liquid absorbents on the market as some are fired at high enough temps and some are not and this seems to vary by region.

However, I have never heard anyone say the fired DE sold as Floor Dry does this.

If you visit a Napa store just look at the bag. While packaging may vary/change, the one I bought just a month ago says 'Better than Clay' right on the front and also indicates it's diatomaceous earth.

Also my "turface" is Profile, which I understand is the same manufacturer anyway, but it is not orange, quite. Although it has a definite orange tint, it is also definitely brown when wet, and slightly different shades of brown at that. Not unattractive at all. I can crush it with my teeth if I try but it seems fairly survivable beyond that. I'm currently doing a wicking test to see how high up the glass it goes at 24h. On 12h right now.

I'll be out today buying repotting materials so I will swing by a Napa before I go to the Landscaping Store and look for 'Better than Clay' on the package.. thanks for pointing that out!

Someone (Penfold) just posted the useful info that the proper part number for their DE floor-dry is #8822. Don't expect the average store sales person to be too well versed in what it's made of or how it performs.

'Profile' makes several types of 'Turface'. You want Turface MVP or the product from the John Deere dealers called 'All-Sport'.

Al

I read that today too (part #8822) and ended up buying myself 7 sacks from the store where the guy said it was white clay. It's really light weight! Unfortunately though I wasn't able to get to Southern States (farm supply) in time to get chicken grit, I will do that tomorrow after I call and confirm it is in fact granite chips. In the meantime I'm going to put this Napa product to the freezer test overnight just to be sure. Guys at the store said I could take back unopened sacks so that's fine if it doesn't hold up.

I looked at my sacks again and though I was sure they were "profile" they are in fact something else, but I can't remember what it is at the moment and my son is sleeping on my lap so I can't get up. I'll post it later when I remember to.

By the by, Al, how often DO you water? Some of my outdoor plants are in full sun for the summer. Just wondering, contemplating.

Thanks again.

Ellie

How often I HAVE to water depends on weather conditions & how robustly the plant material is growing, but I water MOST material in the gritty mix daily in summer (remember, I grow in even faster soils than you'll be using). The display containers & veggies in the 5:1:1 mix get water eveery day to every 3 days, depending on how mature the planting is and other factors.

Al

How far down do you let it dry completely before you water? The gritty mix with bark is faster than a mix of 1/2 diatomite/turface and 1/2 granite chips? Definitely faster than vermiculite I'd wager! Or do you use a different gritty?

Alright I just checked. I have "Primera One Field Conditioner" that I have been using like and calling "turface." The particle size seems about right overall. The lady who sold it to me was very sure it was repackaged MVP, which I could not find locally. The local John Deere guy says the computer redirects him to another product that's much finer when he puts in MVP, as though it's been discontinued? Oh well the diatomite is supposed to be better, right? It held up to freezing.

Ellie

The basic gritty mix I always have on hand & use as the basis for all my gritty mixes is equal parts of
Screened Turface
Screened Grower size Gran-I-Grit
Pre-screened 1/8-1/4" fir bark

Allsport at the JD dealer is Turface MVP packaged for JD only - same stuff.

When growing in the gritty mix, I allow plants to become completely dry - then water the day before.

Al

I thought I remembered you saying you used that. So you allow them to completely dry one time, count the days, then water just before thereafter?

Thanks,

Ellie

Sorry - it was a tongue-in-cheek thing ... a joke. ;o) I let them get rather dry, but try to water before there is any visible sign of drought stress, like wilting.

You really can't count the days, because conditions change markedly & have a considerable impact on what would be appropriate intervals between water applications. What I said about "allowing plants to become completely dry - then water the day before." is actually a quote attributable to a bonsai master (Ben Oki). I was participating in a juniper styling workshop he was leading when a woman asked, "How often should I water (my juniper?" His reply, in perfect deadpan, was, "Wait 'til plant become completely dry - then water day before."

I'm still unsure if he was making a joke, or if it was his less than perfect English that made the instructions come out as they did. Either way, it's still stellar advice. ;o)

Al

"...then water the day before."
That's great! Sage advice, and good for a chuckle, too...Dry humor, one might say... ;)

Re: changing water needs
- I find that I need to heft (lift/move) my containers to verify when the container medium has
become appropriately dry (particularly with my succulents in large containers). I'm still new
to soil-less mixes, and the ingredients in my media have varied over the past year and a half,
leading to further differences in water retention. I tend to rotate my plants every day or so,
which helps me keep an even closer finger on the moisture levels.

Josh

This is true. I thought it was an odd statement but I don't 'get' jokes over the net very well. I guess I need facial expressions to go with. Or smilies. :)

That watering scheme though sounds like exactly what I've tried to do, but with peat based soils in various states of decay with 'organic' fertilizer it became a bit of a guessing game with some of them, or I'd get dirty finger syndrome. Usually both.. Hehe. They limped along and most didn't die probably because I erred on the side of underwatering most of the time. But I don't want to see 'not dead.' I want to see vigorous health. Previously I mostly got "I'm ok, leggy, ugly, tip burned and insect infested, chlorosed and slow growing or NOT growing at all due to cyclical root rot and insufficient nutrient, but alive." Except for the really easy stuff, which grew a little better. And people said I had a "green thumb." Hah. Wait till they see my new substrate knowledge superpowers!
Did you ever play mmorpgs? I did some.. and if you did, then you'll get this. You leveled me. Thank you muchly.

Ellie

lvl +

;)

Just for future reference the NAPA #8822 is called "Super Absorbent".

Great stuff. I insect screened mine then went back and rinsed it while on the screen. You should wear a mask while screening this stuff as it's harder on the lungs than your average dust particles.

If I used an emoticon, it would have been too easy ..... and it would subtract from the droll/dry nature of the comment. Besides - I want you on your toes, thinking fast. See? - no emoticon again.

Al

I'm a little late to this discussion but the mention of the Napa Floor Dry #8822 calcined diatomaceous earth intrigued me so I ran out and bought some for about $7.50/24qt bag. In checking the particle size from the bag I bought, I found it lost 40% through 1/16" insect screen versus Turface MVP which lost 28% through 1/16" screen. Bulk density: packed dry density of unsifted Napa was 0.44 g/ml, sifted >1/16"=0.40 g/ml versus sifted Turface MVP dry packed density=0.74 g/ml. My pore space analysis based on fully wick drained media: Napa sifted >1/16" was 82% total porosity, 36.3% air space and 45.4% capillary water. Unsifted Napa 81% total porosity, 54% capillary water, 27% air space. As compared to Turface MVP sifted >1/16" 75% total porosity, 35% air space, 40% capillary water.

Interesting work, Nathan. You've been busy. ;o)

I think the volume of fines in the floor-dry must vary from bag to bag, because the one I bought & am using with several plants now had no where near the number of fines I find in Turface. I usually use 2/5 of a bag of Turface screening it through insect screen, and 3/5 through #10 mesh. I lost closer to 1/5 of the floor-dry through insect screen.

It looks like & we always knew the calcined DE outperforms Turface in total air porosity & water retention, if that is what the grower is looking for, but I'm watching closely for any effect the higher pH (7.0 vs 6.2) of the DE might have. I don't think there will be any significant differences, but who knows? Looking at stuff closely (as you have) is what makes growing fun and improves your skills.

Al

Al, I think your are right in you observations about bag to bag variability in the proportion of fines in these products.
I haven't done any testing of the pH buffering capacity of these products but I do know that pine and fir bark have a lot of buffering capacity and resist pH change which of course lime or dolomite works well to raise when the need arises. I'm guessing that Napa Floor Dry, being primarily a silica based product and Turface, a clay based product, would have far less buffering capacity and would not resist pH change much. I even wonder if Napa Floor Dry would appreciably affect the pH of a medium containing bark components.
I always enjoy everyone's questions and observations in these discussions. It really makes me think and helps me to understand.
Nathan

Turface is supposed to be chemically inert and nonreactive. It shouldn't have any affect on media pH.