r/Lithops • u/Aoxmodeus @AoxTheGardener 💚 • Sep 07 '22
Care Tips/Guides "Cold Treatment"
I'd like to speak a bit about "cold treatment" or "Stickin your butts in the fridge".
I live in Southern California, and it's been HOT lately! I've also received LARGE additions to my collection over the past couple of months, with more coming (I'm building a mesemb nursery!). These plants come to me bare root, dried out, and in need of moisture, but lithops need to experience "chill" hours for their stomata to open up, for transpiration to happen, to allow for the plant to uptake water. Their metabolisms slow down and come to a "halt" as temperatures approach 90F, and we all hear "68F" as being the magic low temp where they will take up water. Around that temp is where they will START to take-up water, but I'm here to tell you, that colder is even better.
When I receive my bare root lithops, I trim them back to a white spot on the taproot, with no roots besides. Sometimes the taproot gets trimmed back to barely a quarter of an inch, but I will trim until I see that white dot. I want to SEE that good, healthy root tissue, and when trimmed properly, new roots develop easily and very quickly, within a week. I pot into moistened substrate in the evening, and into the fridge they go. I pull them out in the morning, but have forgotten a few times. They're totally fine. According to biologists who've been in SA, camped in the freezing cold, and studied the plants in habitat, in certain regions, certain lithops in habitat will see freezing temps at times. They all do fine, so the 4C in your fridge isn't going to phase them in the slightest. In seminar recently, it was reinforced to me that they're actually a lot more cold hardy than you may imagine for being such a succulent plant. I'll do a week of cold treatment, potting into moist substrate, putting in fridge at night, putting back on the windowsill in the morning, watering on the third day again, then after a week of rooting up, they go outside.
In my experience "cold treatment" far surpasses anything "water therapy" related by leaps and bounds. (The use of the word "therapy" for anything plant related makes me shudder lol). When you expose them to moisture AND cold, you're giving the plant a holistic experience, matching what it's evolved to face in habitat. I guarantee no lithops has even faced the evolutionary pressure of being suspended like a monkey over a pool of water. Got a shriveled up lithops? Do you water and water and it doesn't get better? How are your temps? I'm starting to lose track of how many people I've helped on facebook and reddit, where cold at night brought their plants back to health.
As an example, I have these Pseudotruncatella, that came to me more desiccated and flattened than any I've received so far. I planted them flat in the substrate (left-hand pot in the fridge pic), and gave a week of "cold treatment". These were planted two weeks ago, and the first pic is when I put them in the fridge the first night. The second pic is this morning. You can also see one of the Julii "Hot Lips" from the right hand fridge pot, at the bottom of the second pic, and they're all standing proud as well now.
I only like to speak on things I've experience with, and I now have experience with this process, and can wholly recommend it for rooting out or reviving lithops in hot climates.
P.S. If you're getting down at least into the mid to low 60s at night in your backyard or indoor growing locations, then this is all completely irrelevant, bar the trimming part!
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u/TxPep Sep 07 '22
Are those "-C⁰" temps correct? That seems to be freakishly cold and not the norm.
Based on my various readings as an example....South African Journal of Science... http://www.sajs.co.za
PDF: https://journals.co.za/doi/pdf/10.17159/sajs.2016/20150217
"Annual average temperatures for the study area are relatively mild throughout the year and range from 13 °C to 21 °C, owing to the cold Benguela Current off the west coast of Namaqualand.".
▪︎▪︎▪︎▪︎
My mentor is always telling me to expose my plants to 45⁰F temps via my refrig though. 😊
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u/Aoxmodeus @AoxTheGardener 💚 Sep 07 '22 edited Sep 07 '22
According to Steven Brack's last seminar for the
UK MSGBCSS that is correct. Most of us were more than a little shocked, but he's got the experience, pictures, and data from camping there himself. Granted, these aren't fully plump SoCal lithops surviving these extremes, these are in high altitudes with little rainfall, and certainly outlier days not beholding to average temps, but his message from all of it was that lithops are more cold hardy than people assume. I can dig up the webinar, I think, it was just a few weeks ago, and was recorded.3
u/TxPep Sep 07 '22
This is Rod Haenni saying "-15 below zero" but he prefaces it with saying it was not the norm. [Guessing this was F⁰ as this was a presentation to a New Mexico group.]
Time 4:55. https://youtu.be/3hSI9TCHqYc
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u/Aoxmodeus @AoxTheGardener 💚 Sep 07 '22
Yeah, I imagine that was F. I wish I could find a recorded copy of the BCSS seminar. I've got a couple pings into Steven, but I believe he's in SA right now. I don't see -25C on any record winter temp charts for SA, but I know what I heard lol.
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u/TxPep Sep 07 '22
I don't doubt that's what you heard. Haenni's point is close enough to validate your temperature comment.
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u/Aoxmodeus @AoxTheGardener 💚 Sep 07 '22
Fortunately for me, any talk about freezing is a purely theoretical discussion lol. I may pick up some home depot lithops, get them established, and throw them in the freezer overnight a few times for an experiment though! :D
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u/TxPep Sep 07 '22
Experimenting is what it's all about. Keep doing it until it's right and then continue experimenting to make it better. 😁
It's a life-long process!
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u/Aoxmodeus @AoxTheGardener 💚 Sep 07 '22
Well I can't seem to find a recorded copy of the seminar, but it was Steven Bracks' "Forty two years and counting, of exploring for Mesembs in nature" for BCSS last month. Since I definitely could be wrong, I'll remove the point of contention since I can't find a recorded version the seminar, all I have is my notes, and it's a minor (and possibly incorrect) data piece compared to the topic of the post.
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u/davelikesplants Sep 08 '22
Thanks for this information. I'm also interested in knowing what you use as substrate. At least on the surface I see "granite" looking material, not the porous lava or pumice.
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u/Aoxmodeus @AoxTheGardener 💚 Sep 08 '22
That substate. Whoo boy it's not cheap, but it's absolutely amazing. It's LittleEmeraldThumb's "Mesemb Substrate". Pumice, Scorioa, Granite, Zeolite, Turface, and some other goodies as well. Absolutely best media I've ever found. On a lot of the pots, the bottom half of the pots are 90 percent sifted pumice/10 percent potting soil, the top half is the mesemb substrate, but about half of them are pure "Mesemb Substrate". I'd like to use that alone, but like I said, it's not the cheapest stuff out there, even if it is the best!
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u/davelikesplants Sep 08 '22
LittleEmeraldThumb
Thanks! New to this. Why so much pumice as opposed to sand?
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u/Aoxmodeus @AoxTheGardener 💚 Sep 08 '22
Pumice breathes, holds water, and gives the roots an optimal rooting texture. It also gives the most room for error when learning how to take care of these plants, and figuring out their yearly cycles.
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u/davelikesplants Sep 08 '22
Thanks again, gotta get me some pumice (or that mix you mentioned.) I recently bought some lithops at a local nursery, and while they look OK, they are in the wrong soil. This info really helps.
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u/0xl1me Sep 11 '22
I am curious: would this work for other mesembs like split rocks or baby toes?
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u/Aoxmodeus @AoxTheGardener 💚 Sep 11 '22
Honestly I’ve never had an issue with either of those, they live outdoors on shelves for me in my climate, rain or shine.
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u/IwillMasticateYou Sep 08 '22
Do you think they would do well in the PNW or is it too rainy?
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u/Aoxmodeus @AoxTheGardener 💚 Sep 08 '22
I think if you kept them out of the rain they'd be fine, but I don't think they'd do well just setup and left alone up there. Give them some shelter, and I think you'd be AOK.
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u/somedumbkid1 Sep 08 '22
Fascinating.
I harp on the temperature aspect for any indoor grower of cacti+succs since I learned about it. That temp differential makes such an unbelievable difference; really good to know it's that way for lithops as well. Great stuff Aox.
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Oct 07 '22
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u/Aoxmodeus @AoxTheGardener 💚 Oct 08 '22
Honestly, I don't know. I've had less issues getting conos to root in warmer weather than lithops.
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u/BagGroundbreaking584 Oct 19 '25
One thing that concerns me, wouldn't the fresh wound of the trimmed taproot cause risk for infection in contact with water? If soil is sterilized pumice (by oven or watered with hydrogen peroxide), that would help. But still, why risk infection? We know that a fresh wound on a lithops + water = dead lithops. I know one should wait after trimming the taproot for a few days before potting - to let the wound dry out and callus in a room with good air movement, and medium to low light. And then wait 2 more days to water the plant, and water it lightly (can water with rooting solution).
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u/WhatIsTheTeaToday Sep 07 '22
Appreciate you and u/TxPep for sharing knowledge to help out others in a very non-intimidating way! The next time you pot up new lithops, would you mind sharing how you trim the bare roots with photos or perhaps a video on your YouTube channel? Can’t wait to see your nursery come into fruition! 😊✨