Keith, it is hard to answer your last question without knowing what kinds of plants you have (cactus plants? Sansevieria? Euphorbia? Aloes?) and also how INFREQUENTLY you water (and how infrequently you WANT to water). Adding coir to Miracle Gro soil seems like a recipe for overkill to me.....but then, I am not a coir fan and have abandoned experimenting with it forever.

My first suggestion is, if you have success (and it sounds like you do) with MG soil, why not just stay with it? If you use plastic pots or ceramic pots (something where the surface is not porous, but is "sealed"), you can assume more water retention and less need to water. Using a bag of MG soil is INFINITELY easier than sifting and washing multiple gritty ingredients and having to water twice as often.

In my opinion, you simply CANNOT achieve a mix with any combo of gritty mix materials (Turface, chicken grit etc) that is EASIER than just buying a bag of soil. Many of us experienced way too much water retention with commercial soil, so that's why the migration to gritty mix. Gritty mix is NEVER going to give you incredible water retention -- NEVER. That's the reason WE USE IT in the first place.

All of that said, I live in FL where it's hot hot hot 90% of the year. My plants are all outside on a screeened lanai. Right now, more than 70. They are all succulents--the kind mentioned above and others. SOME are in gritty mix and some are in pure pumice alone, and some are in a combination of soil and pumice. Some are in clay pots, some in plastic pots. With most of them, I water every 10-15 days, sometimes once in 20 days. They manage -- they're succulents.

Finally, if you are determined to use gritty mix, all I can say is -- I don't use what you use. I use Turface. I get it at a John Deere store, and I sift and wash it. I don't like it much but it does hold water -- that's its job. I also use Manna Pro Poultry Grit from Tractor Supply, and I wash it. I love it. Finally, I use pumice from General Pumice Products -- pricey, but a good product. I wash that scrupulously too. I gave up on bark years ago and gave up FlorDry or DryFlor or whatever it is. I HAVE used Grani-Grit but like Manna Pro Poultry Grit better. My most frequent combination of Turface, Manna Pro and pumice is 1:1:1. Good, generic, easy to remember. And yes, I fertilize lightly just about every time I water for gritty mix plants. Hope this helps. Good luck! Let us know what you decide.

Thanks so much for your very thorough response. Some of the plants I'm working with are aeoniums, perle von echeverria, ET fingers, string of pearls, kalanchoe, moon stone, and jade. I was hoping to water once a week. In the winter plants are under grow lights. Miracle grow soil dried out after about a week.

I'm holding onto the idea of gritty mix because I'm a little obsessed. But seriously, I went through such big lengths to find the Grani Grit, repti bark, and flor dry. I mixed so much of it only to end up taking it out of my pots and dumping it into a big plastic bin. Right now I have the Flor Dry, Grani Grit, repti bark, and worm castings mixed together in a large bin. I'm debaitng on whether I should add coco coir to it to make it act a little more like the miracle grow. I could just use the miracle grow, but I like making my own soil mixes and thought I would have some success at some point!

Keith, if you are watering once a week and are ABLE to continue that schedule -- I wouldn't worry at all if the mix dries out. Mixes are supposed to dry out between waterings. In fact, whether you use MG soil or your own gritty mix, I wouldn't worry. I don't grow any of the plants you grow. Used to grow some jade, but -- I have whittled it down to sansevieria, gasteria, aloe, haworthia, euphorbia and a stray opuntia. Regardless, we are both growing succulents -- and their main characteristic is that they don't REQUIRE frequent waterings. They SHOULD dry out between waterings. More people kill succulents by over-watering than just about anything.

As I detailed (probably at too great a length), I am in FL where the heat is beyond description, sometime. I keep written records on all my plants in a 3-ring binder, and record when I water each one (and also if the soil is still damp, long after it SHOULD HAVE dried out). As I said, it's often 10, 12 or 14 days between waterings. They DO dry out and I expect that.

If you're not getting the GROWTH you want, I can only suggest you consider other things. Are they getting enough light? Or too much light? Are they in colder temperatures without protection? With gritty mixes, I believe (from reading here, for years) that you do need to fertilize VERY lightly with each watering because there are NO NUTRIENTS in gritty mixes and there ARE nutrients in soil mixes. I use Foliage Pro 9-3-6, and I mix about 3/4 teaspoon into each gallon of water used. (I pour from a gallon jug into a watering can.) But there is a Miracle Grow liquid fertilizer (Home Depot and Lowes) that has nutrients in the same 9-3-6 proportions (says so right on the little jug) and it sells for MUCH CHEAPER. I have used it and do -- with very similar resuls as Foliage Pro. A small jug lasts a long time.

Finally, if you like manufacturing your own mix -- examine whether you have the same size ingredients (maybe not bark of course). I grow small plants -- 4" and 6" pots mostly -- so I am looking for my ingredients to be about 3/16 of an inch. I even bought a soil sifter at Amazon for that size specifically. I sift the Turface for size. I buy pumice that is about 3/16 of an inch, and the Manno Pro grit comes out of the bag perfectly -- no work required but washing. But -- I do suggest you wash everything, because....dust can strangle a plant. Keep us all posted, Keith! Good luck!

Adjust the ratios and components of your mix for each type of plant you grow and their condition to suit your watering habits. Gritty mix is a concept and not a recipe! You can accept a non-ideal mix for non-ideal watering habits. Gotta live how you want, right?

Totally, it's like a base to build on. I decided to make the gritty mix base and add coco coir and worm castings, which I think Bonsai Jack does with their mix. (They don't add as much as I do, but I did see that as an ingredient.) We will see how it goes! I think adding all the coir makes it more similar to the miracle grow I'm used too. But I'm thinking this will be better because it creates more drainage with all the grit. Trial and error.

My plants don't do well with gritty mix either. I've gone back to using mostly soil

You can add about 15% of fines (<1/8") without seeing a dropoff in plant productivity. That 15% margin is what I think of as the "convenience margin" and it's what increases/decreases the frequency with which you have to water to prevent the roots from drying out to a point where they die off and then rot the next time you water. I just use peat, but coir works too.