Hi All,

I've doing some research on improving the soil mix for my succulents and have ran into a lot of different suggestions. Everything from things like pumice, perlite to things that I haven't even heard of. Like chicken grit, turface, NAPA 8822, etc.

Can someone explain what these are used for (as in what's used for improving aeration and drainage vs what's used as top dressing)? And also what the typical cost is for them?

I've just been using some regular succulent and cacti soil from Home Depot and added some perlite to it. But I've noticed that the soil mix tends to become hydrophobic after a little while, so I am looking to change it.

From what I can tell, pumice is hard to find on the East coast, so that might not be an option for me. I haven't been able to find Turface either but I can get 25 lb bags of both NAPA 8822 (www.napaonline.com/en/p/NFN8822) and chicken grit (www.tractorsupply.com/tsc/product/manna-pro-poultry-grit-25-lb) for about $10 each. That seems like a fairly good price.

Any other sources/products that I should be looking at? Would prefer to stay on the cheaper side, if possible.

Also would any of these products help with traditional houseplants too?

SamuelA said:Hi All,

I've doing some research on improving the soil mix for my succulents and have ran into a lot of different suggestions. Everything from things like pumice, perlite to things that I haven't even heard of. Like chicken grit, turface, NAPA 8822, etc.

Can someone explain what these are used for (as in what's used for improving aeration and drainage vs what's used as top dressing)? And also what the typical cost is for them?

I've just been using some regular succulent and cacti soil from Home Depot and added some perlite to it. But I've noticed that the soil mix tends to become hydrophobic after a little while, so I am looking to change it.

From what I can tell, pumice is hard to find on the East coast, so that might not be an option for me. I haven't been able to find Turface either but I can get 25 lb bags of both NAPA 8822 (www.napaonline.com/en/p/NFN8822) and chicken grit (www.tractorsupply.com/tsc/product/manna-pro-poultry-grit-25-lb) for about $10 each. That seems like a fairly good price.

Any other sources/products that I should be looking at? Would prefer to stay on the cheaper side, if possible.

Also would any of these products help with traditional houseplants too?

Helooooooooooooooo I am not the most good person at this stuff, but i have some tips!!!~~~

Mix:
I'd just go with succulent/cactus mix if it is the easiest to find. Of course, I would add amendmants! Ok, so depending on what to grow, you might want to add sand. For semps I would add a little bit, if you are going to grow companions such as sedum which need more water, you would add more. My mix is about 40% sand, 20% perlite (replace with pumice), strain it so the fine dust is not in the mix, and 50% perlitey-garden-generic-mix. That's because I mainly grow sedum in it.
Chicken grit could also be used, but I think it is the best for topdressing. If it is very humid you may want to add more chickengrit/perlite for topdressing andmix.

You could use it for houseplants, but not for tropical ones. plants such as hoya, and other aroids would be fine, but i'd not use sand and replace it with wood chips or bark shreds from things like orchid mix.

If you do it for indoor succs, again, i would not use sand, I would just use that otherwise.

Thanks Alex.

I am growing indoor succulents for now. A lot of Sempervivums, some Pachyphytums (moonstones), Peperomia graveolens and Echeverias.

It sounds like you are saying not to use sand with indoor succulents. So would you recommend staying with a succulent/cactus mix and perlite?

SamuelA said:Thanks Alex.

I am growing indoor succulents for now. A lot of Sempervivums, some Pachyphytums (moonstones), Peperomia graveolens and Echeverias.

It sounds like you are saying not to use sand with indoor succulents. So would you recommend staying with a succulent/cactus mix and perlite?

Probably, depending on your specific climate. If it is very humid i would not use sand. sand wouldhold some etxra moisture.

Samuel,
If I'm correct the napa additive your talking about is the diatomaceous earth they use to clean up oil spills, it helps stop slugs from attacking your plants if used as a top dressing but stops being helpful when it is saturated with moisture. I think it has some mineral contributions as a soil amendment, probably has some calcium since it's essentially derived from pulverized fossils, but that's more of a hunch for me at this point. I've only recently started adding it to the soil, seems to help.
The grit additives are all very comparable when you get right down to it. I do prefer pumice when I can get it because of its permeable surface which the roots seem to cling to, but essentially scoria, chicken grit, pearlite, and pea gravel are all drainage additives, their density is frankly the biggest difference between them, though each has slightly different properties which have a slight effect on their performance in succulent soil. Any of them will help.

A couple things I feel like you should know: Not all succulents have the same needs, echeveria and most of the subtropical species often used as house plants prefer far less water than sempervivum. They come from dry deserts where moisture is scarce. Sempervivum and ground cover type sedum are from alpine mountain climates, where rain is more common, but drains quickly away from the rocky outcroppings where these plants grow. Ultimately generic succulent/cactus mix is predominantly designed for desert plants, not alpines, though if you water just right it will work for sempervivum to, it's not the best. You'd be better off amending a regular potting soil by adding some inorganic materials like sand and gravel (or whatever you choose to use for drainage from the list above). Miracle Grow Moisture Control has an additive to help with the hydrophobic issue, so that's a good base to start with but any potting soil will work, I use about 4 parts potting soil 1 part gravel, .5 part sand and .5 charcoal. That gives you an easily made mix that works better than the cactus stuff. I hate to discourage you from growing sempervivum, but they do really grow best outdoors also, you can grow them fine inside if you have a good window but they really show their best colors and forms outdoors. Avoid taking them directly from the indoors to an outdoor full sun location though, they need time to develop a "suntan" in the shade or during a season other than summer before they can handle full summer sun.

Regarding Turface, it is an odd manmade material that was designed to aerate grass, and in higher concentrations to prevent the growth of weeds and reduce the mud on baseball fields. You can buy turface at niche sports field maintenance or lawn care stores and 50lbs shouldn't cost you much more than ten dollars, maybe fifteen. Whats odd about turface is that it helps drainage in that it breaks up and loosens the soil, but it also paradoxically holds moisture like a clay would. Not a fantastic material but it could be used to make some improvements. It's best for keeping soil loose, but I haven't really figured it out yet. Used to use it in high concentrations but it added too much air into the soil for plants to stay hydrated. Now I only use it in moderation.

Goodluck,
-Sol

GeologicalForms said:A couple things I feel like you should know: Not all succulents have the same needs, echeveria and most of the subtropical species often used as house plants prefer far less water than sempervivum. They come from dry deserts where moisture is scarce. Sempervivum and ground cover type sedum are from alpine mountain climates, where rain is more common, but drains quickly away from the rocky outcroppings where these plants grow. Ultimately generic succulent/cactus mix is predominantly designed for desert plants, not alpines, though if you water just right it will work for sempervivum to, it's not the best. You'd be better off amending a regular potting soil by adding some inorganic materials like sand and gravel (or whatever you choose to use for drainage from the list above). Miracle Grow Moisture Control has an additive to help with the hydrophobic issue, so that's a good base to start with but any potting soil will work, I use about 4 parts potting soil 1 part gravel, .5 part sand and .5 charcoal. That gives you an easily made mix that works better than the cactus stuff.

Thanks Sol.

This is very helpful to know. I didn't think much about the watering requirements, thinking that all succulents are pretty similar. But it's good to know sempervivums need more water.

For the second part about the soil mix ratio, are those by weight or by size/volume? And also, what type of charcoal is best to use? I know that your regular briquettes aren't supposed to be used for plants but would something like this work: www.homedepot.com/p/Frontier-17-6-lbs-Natural-Lump-Charcoal-195-338-374/313319118 (can't post as a link, as I am a new user).

Also:
Tip for indoor plants:
SIFT YOUR SOIL!!! SYS!!!
If you don't sift it, sometimes the water won[t sink in and will sit on the top. Take a regular big sifter and fill it with mix and shake it so the dust-like dirt stuff comes out. If you wanna see, put that stuff in a paper cup, and put some water on it with a spoon, well just put a little bit. The water droplets sit on top of the dust stuff and is very interesting.

sedumzz said:Also:
Tip for indoor plants:
SIFT YOUR SOIL!!! SYS!!!
If you don't sift it, sometimes the water won[t sink in and will sit on the top. Take a regular big sifter and fill it with mix and shake it so the dust-like dirt stuff comes out. If you wanna see, put that stuff in a paper cup, and put some water on it with a spoon, well just put a little bit. The water droplets sit on top of the dust stuff and is very interesting.

Sift the mix (soil and whatever amendments) or sift each component individually and then combine them?

Samuel,
My measurements are always by volume. I don't think barbecue charcoal of any kind will do the trick, activated biochar specifically is the best, but I use the black charcoal and ashes from a fire pit or my friends wood furnace because it's cheaper than buying biochar from a plant nursery, though that stuff is much nicer. The ash adds a super fine particle to the soil that I'm not thrilled by, so if I want to be careful about things I'll sift out the ash and crush the charcoal by hand as I mix it into the soil. The biochar you can buy at nurseries has no ash, and I think it's been boiled to "activate" it, not really sure on the science there, but I've used ash in a pinch and it didn't seem to hurt anything.
-Sol

I like using sand to add to the mix but I look for horticulture sand, sometimes available in packages. I don't use Playground sand as it is too fine and gets compact. Somebody let me take from her house a few sandbags that were used to safeguard from flooding and the sand was perfect as the grains were bigger and included small rock. Just as good as really small gravel.

Hi everyone, I'd like to chime in here if I may. This is actually my first contribution to this forum. If you can't find pumice, you might want to try lava rock or LECA, for aeration. Im am about to try that myself by mixing it with soil, after crushing the LECA into smaller pieces though. I have seen people grow plants in nothing but LECA, I believe its considered semi hydro. But the LECA and LAVA ROCK are quite porous so they are good for working with microbes. I am going to try this this growing season.

If you are having hydrophobic issues, try using an organic wetting agent!

It's very important that we use the term BIOCHAR and not charcoal before someone gets the wrong idea and goes out and buys the wrong stuff. I have been looking for some but as I understand you must not add it to your garden until it has been saturated with nutrient or it could end up leeching nutrient from your soil leaving your plant with less. So I don't know if it is sold with nutrient already added or if its something we have to do ourselves once we buy it. Also, I have used ash from my father in laws fire place last year and my plants did really well. I expect that it adds an amount of sulphur and calcium to the soil. I don't have a concrete reason NOT to use it again but Biochar from what I hear is VERY good.

Ooh, leca!

Hi JamGrower, nice to meet you. And thank you for posting your information.
Thank you for the info on using the term BIOCHAR, not charcoal. What is the difference?
I have never used either one.
After reading up just a bit on LECA, I can see it would not be my choice.
1. Expense
2. Have to fertilize
I do find it interesting that you want containers with no holes.
My experience with pumice or lava rock is that many plant love growing in it. Here in the PNW it is fun to go onto the lava fields and see what plant grow happily on the old flows.

Wait what container with no holes?

JamGrower, I forgot to ask what kind of plants are you growing?

valleylynn said: JamGrower, I forgot to ask what kind of plants are you growing?

Yes I was wondering the same!

JamGrower,
Welcome to the forum glad to hear from you! Yes it'd be a big mistake for someone to buy charcoal used for barbecues thinking they could break it up and spread it on their garden, and of course charcoal strait from a fire hasn't been washed or treated like quality horticultural biochar has. As for the nutrient leaching potential of untreated charcoal I'd be somewhat inclined to believe it to be possible, (I've had it bleach the color out of my clothes before so perhaps there could be a similar interaction taking place in the soil). In the particular instance of sempervivum (a plant which prefers a lean soil) that might not be the end of the world though, especially when adding other fertilizers to the substrate or using commercially produced potting mixes which contain slow release fertilizers. The question that follows would be WHICH sort of nutrient(s) would it be leaching from the medium? An answer to that would illustrate it's value or lack thereof in a succulent soil mixture. I do not use it in my bonsai soil mixes. What I can say about charcoal (untreated biochar) is this; plants roots grab hold of it's semi porous surface which likely has moisture retention/drainage properties similar to those of pumice or lava rock, it helps to loosen the soil and provides what is initially a bacteria free pseudo organic amendment to the substrate. What I suspect is that it (and ash) makes more readily and more cleanly available those minerals and nutrients found in the more microbial rich composts I've learned to avoid, but I have no proof of this theory, just a hunch. After years of mixing ash and fire-coals into my succulent substrates at a ratio of 1/9, I can verify that it doesn't kill them and that my mix outperforms potting soil straight from the bag, though the ash and coal may have less to do with that performance than my other selected amendments. I wish I could see what was happening in the soil at a molecular level, but all of my work has instead been trial and error, perhaps I can set up a test where I leave the ash and charcoal out of the mix to see if the plants prefer it that way. I'd love to use the biochar that has been treated and washed but it's brutally expensive and difficult to come by in large enough quantities to suit my applications, the reason I say charcoal instead of biochar is because I primarily use the raw waste from my friends wood furnace, not exactly the good stuff but there's certainly enough of it to go around.
I've never tried LECA but I hear good things, might be worth trying someday, I have a source for pumice right up the street which is quite affordable so I've never had to find a substitute but I do like to try new ingredients.
Cheers,
-Sol

My husband has been making biochar. The plan is to give it to our neighbor to use under her chicken bedding, then it gets returned to us with the addition of chickenpoop to then get added to his enormous compost pile. I am thinking I will try adding some, pre chicken stage, to my mix. We are in the process of clearing land and have been moving fires as we go along. Lots of ash and charcoal.

It's sort of like me buying pumice for big bucks. It depends on your location what is available inexpensively. I would like to get small stone from the quarry here, but it's limestone and would change the PH, so I buy chicken grit.
Our woodstove ash goes on my vegetable garden and flower beds along with the small charcoal pieces. Since the husband has been on a soil amendment mission, much of what used to make it into my compost tumbler is now on the ever growing mountain of compost to be used on the pasture. Never thought I would have to fight for carbon.....

Dbfarmgirl said:Since the husband has been on a soil amendment mission, much of what used to make it into my compost tumbler is now on the ever growing mountain of compost to be used on the pasture. Never thought I would have to fight for carbon.....

Sounds like you guy's are on to something there Sharen, goodluck on the compost struggle!
-Sol