Vermiculite will collapse (structurally) pretty quickly.

I use 511 mix for my house plants and it works great. Healthy plants, no fungus gnats, steady growth, and if I throw some controlled release fertilizer in the whole thing becomes very low maintenance. Granted, I'm not growing anything that is even a bit difficult - peace lily, pothos, spider plant, strawberry begonia, fiddle leaf fig, grape ivy, etc.

I've had it turn to mush in as little as a few months.

I also use the 5-1-1 for all my houseplants besides the cacti and succulents and for all my outdoor containers as well. I don't think there is a better mix and I have been using it for going on 25 years!!

Vermiculite is very absorbent and that is its downfall. Once completely saturated or having absorbed as much as it can, it will collapse and compress. It doesn't have to take months....I've seen it do this in a matter of a few weeks!

I am lucky enough to have found a local supplier for pine bark fines. One of my local nurseries sells bags of "soil conditioner", 6 bucks for a few cubic feet (2 or 3 I think, I can't recall), and it is pine bark in almost the perfect size. It tends to have a bit too much fine material, so I sift it through a 1/16" insect screen to remove the very fine stuff, and then instead of adding peat moss I just add back in however much of the very fine stuff I need - I always have enough.

That looks prety good, depending on actual particle size. But 50-50 with perlite is probably way more perlite than you need. OK for cacti and succs but the 5-1-1 only has 1 part perlite to 5 parts bark!!

JG - Would you provide an image of what's in the bagged of soil you showed. It's a product specifically packaged for use in the landscape, but what's written on the bag doesn't necessarily disqualify it from being used effectively for potted plants. I'm concerned it might be much too fine for container medium.

The following addresses your original inquiry. I just can't keep up with you guys!! ;-)

The ratio of water to air in a soil is a very important consideration. Plants absorb moisture most efficiently from a microscopic coating of water on the surface of soil particles and from water vapor in larger pores between soil. They absorb water poorly when it's trapped in its liquid form between soil particles. As the size of your soil particles increases, the amount of water found between soil particles after a thorough watering decreases, and disappears entirely when the size of soil particles is approximately 1/10". Since moist and never wet/soggy is ideal, soils with the least amount of water occupying the spaces between soil particles, all else equal, are going to offer plants better opportunity to realize their genetic potential.

The best way to achieve this arrangement is by using a LOT of particles larger than 1/10", and a small fraction of particles smaller than 1/10" that serve as a way to fine tune water retention.

Changing gears to address your questions:

This mix consists of:

Choir

Fine Vermiculite

Small Stalite

Small sponge rock (perlite)

My questions are:

Has anyone had any experience with this mix or a mix like this? I haven't used this particular soil because it has properties I consider undesirable and I am certain I can make a better soil for much less $, though I freely admit that making my/your own will take some small amount of time and effort. That said, I've never driven a bus, either, but I still know what makes the wheels go 'round and 'round.

If the ingredients are listed in order of the volume they contribute to the soil, I think you'd be better served if you just bought a bag of Permatill (by Stalite) or other expanded shale product, of which there are many, mixed it 50/50 with appropriate size pine bark, added a little peat to adjust the water retention and a bit of lime to provide Ca/Mg and adjust the pH upward a bit, and used that or variations thereof, depending on the plant material you're working with, and called it a day.

If you're interested in knowing why I have reservations, aside from the water retention issue, I'd be pleased to explain.

Al

It looks a bit more composted than I would prefer, but I think it's still quite usable, though I think you'll need more perlite than you would with a less composted product. I'd try a plant or two in

3 parts of what's in your hand

2 parts of coarse perlite (if coarse is available - usually is in very large bags [4 cu ft is the norm])

If you find that 2 water-retentive, you can use a wick or add some ballast when you establish your plantings. Ballast, used appropriately, is a very effective antidote to excessive water retention.

Al

There are all sorts of things you can use as ballast. Bricks, empty soda bottles, blocks of foam, over-turned pots, blocks of wood, .....

After you read this, ask any ?s you might have.

Al

So, how do I know how night the PWT of this soil is? Get a clear plastic cup at least 6" deep - heat a nail or screw and use the head to melt a hole through the bottom of the cup - seal the hole with tape that won't come loose, or nest the cup in another cup exactly like it - fill the cup with your soil and fully saturate. It should soak for an hour or so. Top off water as needed - remove the tape or lift the cup with soil out of the cache cup and allow it to drain - you'll be able to see delineation between soil that is completely full of water and soil that has air between the larger particles - that is the maximum ht of the PWT for that particular soil.

Make a note of the information. You'll want to know if you need to use ballast. Your ballast should be arranged so it's at least the ht of the PWT. Make sure you understand how to use ballast effectively. I have no question that your soil will work well if it needs ballast, and it may not. You might be able to eliminate nearly all of the PWT by use of a wick. To test - push a toothpick up through the drain hole once the cup has stopped draining - note how much additional water exits the cup.

I don’t think it is giving me the free flow of water that should be coming from a 5:1:1 mix. That's fixable. We don't care how fast the water drains, only that it does. It seems to hold and if I tip the pot, I can get a bit more to drain out. Any planting that utilizes a soil that holds perched water will do that. Compare line drawing B to A below. The shaded area represents the PWT. You can see it's the same ht in all of the pots (except E). When you tip A to the position in B, the PW column gains ht. This increases it's gravitational flow potential. IOW, there is more weight pushing down on the water below it as the water column increases in ht - just like stacking bricks on a pallet. Every brick added increases the weight pushing down on the lower bricks. In the case of the PWT, the added weight pushes the water below out of the drain until the PWT returns to whatever it is. Try the experiment with a saturated sponge. Hold it flat - like a deck of cards would lay on a table - until it stops draining. Then, change its position so the longest dimension is vertical. You'll witness a LOT of excess water draining from the bottom of the sponge.

How do I know if it is draining “enough” to benefit the plants and do you think the gypsum is a negative factor? Ideally, you want the PWT to be from 0-1" in ht. Once you get to that point, you can water at will to the point of saturation, not withstanding fits of lunacy that would find you watering daily or more frequently. ;-) I'm not sure why the gypsum was included, but since it's represented at a lesser amount than the lime, I wouldn't be concerned. It doesn't change pH and plants are rather flexible when it comes to the Ca:Mg ratio in media.

Lastly, this is the mix after I ran a bit of water through it. Do you think the bark is too fine? The PWT test will tell, but even if it's too fine w/o ballast or a wick, it's still going to be usable. Don't worry - you're on the right track.

Did you mention where you live? Just a large city near you is all I need - not asking for an address. ;-)

Al

I don't doubt for a second that you'll be more than ready, with a really productive medium by spring.

Until next time ..... Al

Al,

When you say "coarse" perlite, what size are we talking about, exactly? I have a great hydroponics store nearby that has everything from typical Espoma products which are pretty small diameter, all the way up to these giant nuggets that are over an inch! Should it be in line with the bark and sifted to 3/8" - 1/2", and leave the dust and smaller bits out? Or do we sift out large and small and use what's left? If the latter, what size small screen are we aiming for?

Some bags have sizes on them such as: #2, #3, #4 etc.

This question has been on my mind for a year and I can't recall ever asking you, or maybe I did and all the information is coagulating in my noodle.

How to read this info: of a given sample size of coarse grade, 5-30% is retained above a 4 mesh screen - the rest passes. 65-70% of what passes the 4 mesh is retained above the 8 mesh screen - the rest passes. 90-100% of what passes the 8 mesh screen is retained above the 16 mesh screen.

To determine what % passes the screen, subtract the %s retained from 100%. IOW, if 5-30% of the sample is retained by 4 mesh, it must follow that 70-95% passes.

Coarse, or "propagation grade" should consist of

4 mesh or 3/16" w/ 5-30% retained (by volume)

8 mesh or 3/32" w/ 65-70% retained (by volume)

16 mesh or 3/64" w/ 90-100% retained (by volume)

Medium, or "soil mix grade" should consist of

6 mesh or 1/8" w/ 0-10% retained (by volume)

8 mesh or 3/32" w/ 40-50% retained (by volume)

20 mesh or 1/32" w/ 90-100% retained (by volume)

I don't use nearly as much perlite as I used to, but I keep only these 2 grades on hand, and I often mix them together at various ratios, depending mainly on the size of the bark I'm using for the 5:1:1 mix.

Al

Hi Joey,

That Hoya looks happy but pls. be careful w/ that double potting. Looks a pretty tight fit & makes me wonder abt checking for water collecting in the bottom of the outer pot which could rot your Hoya's roots; just so you know. I grow Hoyas too ;>)

No problem! When I have repotted plants I give them a good drink right away then water as needed, I don’t do any additional watering beyond that. I’m not sure if extra watering would help/harm/or be neutral to the plants roots, hopefully someone else can answer that part of your question.

Hi, Joey. Over the course of the last few days, I've been spending more time at the citrus forum than I normally do in debate about the impact the air:water ratio in media has on the likelihood of root rot, and it's effect on root health and the o/a potential of the entire organism/plant.

https://www.houzz.com/discussions/lemon-tree-losing-green-leaves-dsvw-vd~5607649 

I'm still following here, though.

Joey asks: Once I’ve switched the plants over to it (3 pothos, 2 peperomias, a philodendron, and a Hoya), will I need to water them more often until they get acclimated to the soil? First, if you haven't repotted many plants, I think you might want to alter your soil a bit and do a do-over. If what you have in your palm is representative of the entire batch, you're probably going to have too little water retention - unless you enjoy watering. If the whole batch is just like what's shown, I'd add 1 more part of perlite and another part of peat. The perlite will get between the bark flakes and create more air porosity, which will largely be filled by the peat. The result will be a soil with more water holding ability (in the peat) with no (or VERY little) sacrifice in total air porosity or air porosity at container capacity (when the soil is saturated but has stopped draining). Your plants won't really acclimate to the soil. They'll want the same conditions no matter what medium you use, you'll just need to water more often. This does not mean the potential in your soil is diminished because of its porosity, not at all. Unless it gets to extremes, the more often your planting needs watering, the easier it will be to keep plants happy. You just can't forget to water at appropriate intervals, and have to be up for watering more often. Personally, I'm excited for you. I think you've done a really great job and should expect a pleasing return on your investment.

Good advice from Lantana & Karen, BTW.

Al

Joey, I am in Cedar Rapids also and trying to make gritty mix and 5-1-1 but am having trouble finding pine bark fines. Could you tell me where you found yours? I have been to quite a few stores and garden centers looking for it.

Illstep are you in Iowa? Just wondering where the nursery that sells pine bark fines as soil conditioner is at. Could you share name & location? I have been searching all over Cedar Rapids looking for it.

Do any of you have an Agway nearby? The attached photo is what you want. Show them this photo and any Agway can cross reference it. Sometimes it is packaged in Agway brand bags, my local store doesn't do this as it costs $1/bag more.

Hope this helps!

Went to Blooms on Blairsferry Rd and left my name and what I want -Pine bark fines -for the person who orders supplies to check & see if it was something they could order. Treegeek, is this product - pine bark fines - almost all useable for our gritty mix & 5-1-1 or is there a lot that can't be used? If it's good, I can show her this picture & that might help sway her to order some.

Joey how much is the bonsai jacks bpd & how much is shipping?

*pine bark

It keeps correcting me. I mean pine bark fines.

Mary Joe, checkout this thread I started and added many photos to. I think once you see the material needed, it will all click, I hope!

Screens are so cheap and take 10 minutes to make, at the very least pass it all through a 1/2" screen/wire cloth to get the big chunks and long sap wood pieces removed.

Main link here: https://www.gardenweb.com/discussions/5552410/pine-bark-fines-for-511-boston-area-help

Treegeek: can you post a picture of the contents of your Pine Bark from Agway? What I get is the Agway brand which is pretty good and mostly usable for 511 straight from the bag. A prior discussion on Agway bark is here: https://www.gardenweb.com/discussions/5217373

Bonsai jack stuff is sifted for bonsai purpose (1/8-1/4) as far as I know. Shipping will be expensive, I would think.

TG: Never mind your link has the pics.