My Favorite Soil Recipes in 2020
Soil is something that I care a great deal about and I am always looking for an excuse to try a new recipe. At the moment, I probably have about 20 different potting mixes going and there are definitely some that are proving to be winners. It is beyond the scope of this particular post to go into specifics about soil components. Today I am here simply to share three soil recipes that I am completely in love with (and will continue to use!)
The one characteristic of each recipe that I’d like to draw your attention to is the ratio of chunks to dust (think bark chunks and potting soil.) All of these mixtures contain at least 2/3 of chunky components. This improves the drainage and the levels of oxygen available to the roots. The specific ratios create certain conditions and if you were to alter these proportions you could end up with a drastically different result.
Please keep in mind that these recipes are for growing in containers specifically. I don’t know anything about raised beds or gardens. The closest thing I have to a yard is a 3rd floor balcony!
One last thing before we jump right in: I live in California and all of my windows face WSW. My plants are never further than 4 or 5 feet away from the window - plant health and growth is a top priority for me. While I will personally vouch for every recipe I am sharing, these soils may not work the same in your climate. That being said, I believe that these recipes will work very well for the vast majority of gardeners out there.
So let’s get our hands dirty!
Soil Mix #1
“All Purpose Classic”
1 part bark, 1 part potting mix, 1 part perlite
Analysis = 33% bark, 33% potting mix, 33% perlite
67% chunks, 33% dust
I have found this to be an excellent mix for just about everything.
This is my go-to aroid mix. They love it.
Bark size: 1/12” to 3/8”
Potting mix: Ocean Forest
Perlite: 1/12” and larger
This is the most well-rounded mixture I am sharing today. It is not the most high-performance soil but it has proven to be an effective mix for a wide range of houseplants. My tropical plants and aroids love it. I am even using this for my succulents now, but I make sure to pot them in clay only. If you used this for succulents in a plastic pot you might run into issues with excessive moisture. The only plants I would not recommend this for are cacti. Cactus need a bit more grit so I’d add 1 part lava, pumice, granite, or another part of perlite. My outdoor ficus love this mix but I use chunkier mixes for my indoor trees. I’d estimate that I have roughly 1/3 of my entire collection in this mix currently and that number is increasing. 1/3 of my plants may not sound very significant, but believe me, for someone who loves experimenting as much as I do, this is A TON!!
I used to have all of my plants in high performance mixes but as the plant count continued rising it became too much. This mix has allowed me to continue growing my plant collection without losing all of my free time to watering or sacrificing tons of growth. I’ve found that, even in summer, I am only watering every 5-10 days with this mix (which is exactly what I was hoping for!) The plants in this mix are growing well and many of them are very nearly keeping up with my plants in gritty mix, with a fraction of the effort. This mix actually made me rethink the super chunky recipes I had previously favored. Don’t let the simplicity fool you:
This really hits the sweet spot between performance and effort.
The bark should be chunky, up to 3/8” in size (1/2” is okay). I sift mine to be between 1/12” and 3/8” so that there’s no dust. You don’t have to do this but if your bark contains lots of dust it will alter the ratio of chunks:dust that makes this such a balanced mixture. You’ll probably still end up with a nice mix but it won’t be exactly replicable from batch to batch. If a large portion of your bark is over 3/8”, the mix won’t hold nearly as much moisture and you would probably need to water every 2-3 days. You could get faster growth that way, but you’d need to water/fertilize constantly. Obviously, that is not what we’re going for with this mix!
For the potting mix portion, just use your personal favorite. I used Fox Farm’s Ocean Forest this year and it has worked well. You can also substitute coco coir or peat moss if that’s your thing. I’d avoid anything that contains moisture-boosting crystals as that will drastically change the performance of this mix.
For perlite I am using the Vigoro brand from Home Depot. This is readily available for me and has plenty of chunks. I have used it unsifted in the past but I prefer to remove everything smaller than 1/12". This helps me get the exact percentage of chunks to dust that I want in all of my mixes. Make sure you wear a proper mask when sifting perlite (N95 or better) as the dust is really nasty stuff and has been found to cause lung issues over time (silicosis). Goggles aren’t a bad idea either. Seriously, the kind you’d use for woodworking or chem lab.
Notice how cool I look!
You could substitute pumice or lava if those are easier for you to find locally. If I had a good source of pumice I would use that instead of perlite since it is less likely to float to the top of the pot. I tried substituting lava for several batches and it was fine except that the particles I used were mostly 1/4” and larger so the mixture held noticeably less moisture.
An additional note about pot sizes: once you get into pot sizes of 3-5 gallons or larger, where you will likely go more than a single year without a repot, I would definitely suggest using recipe #2 instead of this one, as it is much better suited to long-term planting. I recently planted a philodendron in a 3 gallon pot with this mix (my largest philodendron!) and even though it is growing well, I get the feeling that it would benefit from a bit more air and faster drying times.
What I’ve grown with it:
Monstera deliciosa, syngonium albo, pilea peperomioides, various snake plants, ficus elastica, ficus lyrata, ficus ginseng, ficus benjamina, various alocasias, various philodendrons, helix hedera, various succulents (in clay pots - important), nasturtiums, ctenanthe burle-marxii, stromanthe triostar, various calathea, pothos, dieffenbachia
Soil Mix #2
“Bark Plus Pro”
2 parts bark, 1 part potting mix, 1 part turface mvp
Analysis = 50% bark, 25% potting mix, 25% turface
75% chunks, 25% dust
A higher performance mix that is especially well-suited to trees (ficus, dracaena, etc.)
Bark size: 1/12” to 3/8”
Potting mix: Ocean Forest
Turface MVP: unsifted
Due to the higher percentage of chunks, this mix will provide more oxygen to the root zone, resulting in increased growth rates. This is more ideal for trees than the first recipe. The trade off is that you will need to water slightly more often. This is the choice we make as gardeners: more growth = more effort!
Why turface?
Originally, I was using perlite instead of turface and calling this “bark plus”. That was a great mix as well, but by using turface instead of perlite, we can increase the overall moisture holding capacity without changing the very favorable 75/25 ratio. Turface is usually available at various landscaping companies, tractor supply stores, and sports field suppliers. I’ve only personally found it via landscapers but there are many different sources throughout the country.
If you don’t have turface, just use perlite! It still works well and it is a heck of a lot lighter. My first choice is turface for the added moisture but I actually just repotted a large ficus with perlite instead because it is in a large, thick clay pot and is already heavy enough.
I have found this to be an excellent choice for ficus or dracaena. My ficus Audrey is going nuts in this mix, even though it was subjected to a harsh root pruning 2 months ago!
It works okay for aroids but they seem to prefer the first mixture. I have not gotten faster aroid growth with this mix and will continue using the 1-1-1 mix for them.
The high percentage of bark ensures that this mix will last for a long time. Bark breaks down very slowly and can often last for several years in a pot. This will be affected by watering frequency/rainfall, freeze/thaw cycles, temperature, humidity, and freshness of the bark being used. Bark is also very light and that makes this an excellent choice for larger containers (turface is quite heavy so if weight is a concern, use perlite instead.)
What I’ve grown with it:
Various ficus, various alocasia, various philodendron, various aralia
Soil Mix #3
“Dirty Mix”
1 part bark, 1 part potting mix, 1 part turface, 1 part lava rock
Analysis = 25% bark, 25% potting mix, 25% turface, 25% lava
75% chunks, 25% dust
The high-performance special!
Bark size: 1/12” to 3/8”
Potting mix: Ocean Forest
Turface MVP: unsifted
Lava rock: 3/8” and smaller
This is the highest-performing mix on this list. It holds the least amount of moisture and requires more frequent watering. It is also the most highly aerated. This gives roots more frequent and abundant access to water, nutrients, and air. You will be rewarded with tons of healthy growth but you will need to work more for it. I highly recommend using this mix on a handful (a dozen?) of your favorite plants and putting the majority of your collection in recipe #1. This is not as labor-intensive as gritty mix but it is getting close.
That being said, I do find that this mix is very easy to water. It absorbs water well, and it flows throughout the entire pot easily. Compared to mixes that are very high in bark (like the famous 511) this is much easier to re-wet and it can be accomplished with much less time and water.
I could be imagining this, but….there seems to be a natural synergy between lava and turface. Something about that combination just seems…special. I have no reason to believe this other than the fact that it’s just a tangible feeling I get! You could certainly find appropriate substitutes for your own mix but if you can find these exact ingredients I’d strongly encourage you to try them out.
This is quickly becoming my favorite mix of all.
Those with a keen eye will notice that this actually IS my favorite gritty mix recipe with an added part of potting mix. (For the gritty mix I use equal parts of bark, lava, and turface, although, they are sized from 1/12” to 1/4” for gritty mix) I’ve found the addition of potting mix to be very beneficial for my tropical plants.
I am still getting most of the benefits of gritty mix and watering every 3-7 days instead of every 1-3.
That’s a huge bonus! For any tropical trees or aroids I had in gritty mix, they seem to greatly prefer the addition of potting mix. I’m actually planning to use this instead of gritty mix in most situations. This definitely is directly related to my bright and hot conditions here in CA, so if you live somewhere wet and cold, your plants might enjoy it less!
You probably noticed that this has the same ratio of chunks to dust as soil #2, and yet, here I am claiming this to be a superior mix in terms of performance! This is because of the proportions of organic to inorganic material. In this context, organic just means anything that was once alive (as we commonly define it.)
Organic soil components include: bark, peat, coco, rice hulls, potting soil, humus, worm castings, compost, etc.
Inorganic soil components: lava rock, granite, pumice, perlite, turface, akadama, leca, etc.
The dirty mix is 50% organic and 50% inorganic.
The bark plus pro is 75% organic and 25% inorganic.
That 25% difference is huge!
I will eventually have quite a few plants growing in this, but I actually discovered this mix after nearly finishing my repots for the year. I wish I could point to a large portion of thriving plants as proof of this mix’s quality, but that will have to wait! All I can say is that it’s been a joy to use and a joy to look at; I love it!
One other option for creating this mix:
3 parts used gritty mix
1 part potting soil
I have lots of used gritty mix lying around (actually I have a 5-gallon bucket full of it!) It is not even close to breaking down and so I wanted to come up with a way to reuse it. By mixing it 3:1 with potting soil I am creating the exact same 75/25 ratio I would get with the “proper” dirty mix recipe. My favorite composition is still the original: bark, lava, turface, potting soil, but the versions I have made with used gritty mix all perform very similarly. The only real difference for me is that some of my older gritty mixes contain granite, and that creates a mixture that holds noticeably less moisture. I personally have no use for granite here in CA, but if you live somewhere colder/wetter, it can be very helpful.
What I’ve grown with it:
Dracaena compacta, aglaonema pictum tricolor, hoya carnosa
Final thoughts:
I really hope that this helps get you started on your journey of coming up with your own recipes. I highly recommend that you start with some of these and then tweak them more to you and your plants’ liking. If there is a particular blend you are considering, I’d love to hear about it! There’s a good chance I have already tried something very similar. Together, we will attain soil mastery!
Cheers and happy growing!
