Yes, but using too much negates the benefits of the large particles. Imagine: You have a quart of marbles in a quart jar, so the jar is full of marbles - right? You can still add a pint of sand to that jar of marbles though - right? So how do you get a quart and a half in a quart jar? ;o) You know that drainage and aeration was awesome when it was just that quart of marbles - yes? Yet, by restructuring the 'mix' so only 1/3 of the o/a volume of the mix is comprised of fine particulates, you can see in your mind's eye that the entire mix took on the exact drainage characteristics of the sand only. The marbles have no effect on drainage (flow-through rates) OR on the ht of the PWT. After the sand is added, the ONLY thing the marbles do is take up space that MIGHT otherwise be occupied by sand + water, thus it simply reduces water retention w/o adding aeration or lowering the ht of the PWT, both of which would be remedied if the soil was more than about 85% larger particulates. This also explains why those suggesting that you can simply take a peat-based bagged soil and simply add more perlite and some bark to improve it. It won't .... for the same reason the marbles were ineffectual at improving drainage and aeration. In that practice, the bark does very little or nothing to improve aeration (just like the marbles) and it is very ineffective at reducing water retention because it holds almost as much water as the peat. The only significant benefit comes from the fact that the perlite reduces the soils ability to hold water. Going totally technical, the only perlite that is effective is that which is occupying space WITHIN the PWT because all the soil above the PWT would be sufficiently aerated and wouldn't need the perlite. The benefit from bark and perlite comes not from the materials themselves, but from the air spaces between the particles. If your amendments aren't increasing aeration, they serve little purpose & you may as well stick with a bagged soil because you're not changing anything of significance until, again, the large particulates are more than 80% of the mix. Al

Hi Al/plantcrazed/et. al., I thought I should come back and share some results from my "experiment" that I started at the end of April. The controls in my little trial were almost non-existent, but I think that actually makes the results more relevant to me and my growing conditions (and hopefully others will get something from this too). Back in April I got an order of leaves of 19 varieties of AVs. 14 came as pairs of leaves, so I decided to try growing them in different media. As I described in my post in mid-May, 14 leaves went in 100% vermiculite and 19 leaves in 100% turface fines (the smaller stuff left over after sifting for other mixes). The planting tray is an old kit I had leftover from years ago that has a clear cover for germinating/propagating. I had grand plans to carefully measure watering, leaf condition, first sign of roots/new leaves, etc. (like a good experimenter would), but the same day I planted the leaves my toddler ended up in the ER, kicking off several weeks of stress and doctor's visits, not to mention usual life events and adventures when working full time and caring for a small child. My plant care regimen settled in to, basically, watering when I noticed they looked dry. After the plantlets started to appear I took the covers off the trays, but otherwise I've just watered and left them under fluorescent lights and hoped for the best. Here are my results. Vermiculite 4 have plantlets, all of which seem to be growing alright 5 are mostly-dead or all-dead 1 formed a nice-looking plantlet that subsequently died, tho the leaf is still there and has roots 4 have roots but no sign of new leaves (yet?) Turface fines all 19 leaves are still alive 16 have multi-leaf plantlets 1 has a new leaf just beginning to appear 2 are strongly rooted and some gentle investigation revealed new leaves that just haven't broken the surface yet (I had just finished watering when I took this photo, which is why the turface shows wet and dry spots. This is what my usual watering of this tray looks like) A few other observations: the leaves of the new plants in the vermiculite are larger than any in the turface the leaves of the new plants in the turface are much smaller, but there are many of them, they are a strong green colour, and have a vital appearance (my experience tells me these are stronger plants than in the vermiculite) one variety was not in very good shape when it arrived. I considered complaining to the store owner about the quality, but see above re: bigger life priorities right now. That variety didn't survive more than a few days in the vermiculite. The leaf just rotted away. In the turface, it slowly rotted up the stem towards the leaf, but then rooted from the remaining piece of leaf and now has a lovely little plant growing: What these results say to me is that, for my horrible, neglectful treatment of these leaves, the turface was a better growing medium. I'm sure Al or Kevin/ewwmayo would have the correct terms for the properties of the two media, but I would say it seemed like the vermiculite contributed to a less stable environment - it went from a soggy mess when I watered to very dry, very quickly - and the turface was much more stable and allowed these poor things to survive despite my neglect. I've read some of the very lengthy threads about the properties of the various gritty mix ingredients and it makes sense to me that a plant like an AV that doesn't like to dry out but also hates being soggy would appreciate the turface's qualities of holding water but allowing for drainage and air movement through the medium. I think from now on the turface fines will be my preferred method for starting AV leaves (and likely other similar plants like episcias or begonias). I also moved two other AVs (a standard and a mini) into a modified gritty mix (1:1:1, but perlite in place of bark). So far nothing meaningful to report, though neither plant has bloomed and the mini seems to be happier than the standard. But with my neglect of the plants lately I don't think these results are meaningful, beyond saying that AVs can actually survive in the gritty mix even with an inconsistent and sub-optimal care routine. If there's anything interesting to report as these AVs continue to grow and I pot them up (likely into a gritty mix of some sort), I'll be sure to come back with an update. I would happily accept comments/questions/criticisms of my results, but please be kind in your criticisms of my care routine. I might be bad with my plants, but this little one is thriving: Thanks everyone, Melanie

@Nil13 made reference to the Whitcomb 311 mix, which is an earlier historical attempt to create a more coarse potting soil for container plants. I think it is extremely helpful to read a document written by Carl Whitcomb that explains how he came on this formula by accident. Essentially what happened is he accidentally left nine test pots under a bench and everyone forgot they were there. They had successfully nearly killed all of their test plants by watering in a normal potting soil mix and the unwatered plants started to do very well. What I have started to realize is that any plant can do well in many different soil mixes, if you are able to carefully control the watering. This explains why so many people on this forum claim gritty mix is not as good for their succulents as their (fill in some random horrible soil with lots of small particles) mix. Inevitably those people are growing their plants indoors. They have enormous experience with their plant type and they know exactly when to water the plant. So that is the case of a very skilled gardener compensating for a very bad soil. What gritty mix does for me is let me grow succulents outside in very abusive weather conditions, without the plant dying. A plant can get a week of rain and it will still drain well. During Summer, gritty mix will tolerate a bit of overwatering, although you still really need to pay attention to not overwatering. Whether you make your 511 mix with perlite/peat, or with two parts Turface, or with lava and pumice, is probably in the big picture not going to be the deciding factor in whether your plants grow well or not. Success can be add with any of those mixes because the size of the particles allows the roots to breathe and prevents capillary action of water from bring the perched water table to the top of the pot and drowning the roots. Fine-tuning how you make 511 is a question of matching the plant type to the moisture retention of the soil and to the watering habit and climate exposure. Any 511 variant is going to do better than almost any commercial potting soil because of the larger particles used in the majority of the mix.

Bingo! That is where I get mine. The regular pine bark mulch in the blue bag is very good. They also sell 1/2 and 1/4 inch hardware cloth (wire) if you did want to sift. http://myagway.com/catalog/product/117217/agway-pine-bark-mulch-3-cuft#.WH-mdSMrKiY I also found some nice soil conditioner in Stauffers. I bought a bag to see what it was like, and it was partially composted. Perfect for 5-1-1. I went back to get a few more bags, and someone had bought the rest of the pallet! Luckily they got more. I'll have to look at the bag and post what the brand is.