I'm wanting to transition to a soiless medium for at least some of my favorite Haworthia. I'm curious what other options there are besides akadama before I jump in. I've heard of people using a mixture of rocky components, but what about things like leca, vermiculite, orchid bark? What have you tried and what do you like best?
by CasaHaworthia
5 Comments
I have most of my plants in either straight pumice or a mix of pumice and perlite
I once bought an H. obtusa hybrid and found it was potted in 100% inorganic substrate. Some DG, pumice, lava, akadama. If I knew the exact ratio I would include it but I am insure. The plant is doing great and I have now repotted all my Haws in similar substrate. When I do a thorough water I will use some light fertilizer so that they can keep their nutrients up but other than that they seem to really like full gavel mixes imo. Picture included of the Haw in question
https://preview.redd.it/zwh3bmq1d3cf1.png?width=3180&format=png&auto=webp&s=b7b970a4687fe3f22b13262ed2ee3c0b7f92c802
Pumice, lava rock, Seramis. Most of my Haworthias grow fine in inorganic substrate, only blackburniae doesn’t seem to like it, so I mix in good amount of ordinary houseplant soil for them.
Adding: granite chips/grit, biochar/charcoal, expanded shale, surface/calcined clay (uk folks can get that as kitty litter), napa 8822 (not my favorite cause it degrades easily but cheap and available) coarse sand, vermiculate (though those last two are much more moisture retentive)
Id not include bark chips. Sure it’s not nutritive but it’s moisture retaining and large pieces normally. Typically you want finer organics so they’re evenly spread and you don’t get a wet spot rot the root that finds it and then that spread. Bark chips are nice for orchids because they retain less water than moss and break down more slowly but I’m not sure they fit in with haworthia needs. Maybe a finer bark and in low percentages to adjust moisture retention a bit if you need that.
I’m currently planning on taking most of my plants out of akadama and switching to a more cost effective mix of 3-4 parts pumice to 1 part seramis. Most of my plants did okay in akadama, with some hard leaf haworthias doing amazingly, but the results I’ve gotten so far with the pumice/seramis mix have been a lot better (faster and deeper rooting, less transplant shock, faster growth).
In my climate, akadama made a lot of my window haws grow these really weird “runner” roots on the top of the soil that never actually go down into the pot.
For your question:
Leca: it could work, assuming you break some of the balls to make the grain size vary a bit
Vermiculite: unless your climate is warm and dry I wouldn’t recommend using vermiculite, I used it for small seedlings and it attracted fungus gnats, stayed way too wet and broke down pretty fast.
Orchid bark: to be honest I’m not sure, I haven’t used it in my mixes, but I would say that the large pieces of bark I usually use for orchids are definetely not suited for haworthia, which are a lot smaller and will struggle getting their roots around a 1in piece of bark. Maybe smaller bark could work, but just like with orchids you have to be careful with the breakdown period of the wood, since decomposition in the substrate tends to have unpredictable effects on plants.
If you have access to a lot of substrates I would recommend trying out adding a small amount (10-15%) of decomposed granite to your mixes. I used to use pure flint chicken grit as a substitute and it worked really well for keeping the plants anchored.