I would not imagine those tips are getting burnt if they're so far from the lights, but I have no experience with artificial lights so that's just a guess based on the picture.

I have seen that sort of thing on a different species of stapeliad, and some tips seem to die back for whatever reason (none in particular that I can identify beyond the general downturn that tends to happen here during our annual summer drought).

I suppose I could have studied that phenomenon and figured out why it happens, but I have opted not to and just accept tip dieback as an occasional part of the plant's lifestyle. It tends to branch prolifically. So even though not all of those branches have an equally bright future, the number still keeps going up over time.

You're in for some flowers on those Euphorbias in the near future. Both of your plants are flowering size, and maybe you even have a mating pair. The blooms are teeny tiny (even for a Euphorbia) and appear on my plants during late winter and spring, toward the end of dormancy; in some other places during summer. If you are observant and these plants continue to thrive, you may wish to get out a fine paintbrush at some point.

BrendanCS said:

Any ideas what the white growth might be? A giant root? There seem to be one or two normal sized roots coming out of it. I've never had a Stapelia with a growth like this so I'm curious to see how it does.

I believe what you are looking at is a new growth stalk not a root. It would normally grow out of the soil but as this has been under perlite and water it is still white.

Interesting about the Stapelia Baja. Now that you mention it some of my larger ones have done that at the tip but not one of these small ones, so I guess I just assumed it had burned.

I'll keep watching it now that the lights are further from them and see if they at least green up more. A lot of them got pretty dark under the lights but I've seen some of them already go back to green after taking them out from under the lights to repot last week.

I'll watch the poissonii's too. I love their weird white branches and dinosaur looking leaves so hopefully they'll grow healthy (especially the one without leaves)
I wonder if placing that on the heat mat might wake it up out of dormancy.

The flowers look interesting on google. Do they show up on the circular points that the leaves come out of?

Pod, thanks for the tip on new growth. Hopefully it grows up through the perlite into a new arm 👍🏼

BrendanCS said:The flowers look interesting on google. Do they show up on the circular points that the leaves come out of?

Like this... (photo of immature cyathia from late February)

Baja, looks beautiful. I'll keep my eye out on the smaller Poissonii to see if it shoots out any flowers. I gave it a little water yesterday and placed it under my lights again but off the heat mat. I'll see if it continues to shoot out leaves like it's been doing.

The taller leaf-less poissonii's top looks like this still (minus the leaves). There hasn't been any signs of new growth but I'm guessing it will come out of the top? Do they stay dormant for a while?

Hi @jamesicus

I'm still busy repotting all of my smaller succulents and euphorbias into my semi-hydro setup and I was wondering if you have ever grown these types of cacti in semi-hydroponics?

The smaller is an "old man cactus" and the taller is a "silver torch". They're both really new to me, but I only have a few cactus in my collection and the others I've grown in their soil from wherever I got them and water very little because I'm scared of rotting them. They tend to shrink/thin because I probably don't water enough. These two are "hairy" types and smaller than those other cacti, so I was thinking of putting them in clear pots in my perlite/water on heat pads under my lights since they'd fit. But I know this goes against the rule of cacti not wanting a lot of water.

Here is an update on all my small plants and a few big ones repotted in this system. I'm using the top aquarium gravel to keep the dust from the perlite down and to slow down evaporation of the water reservoir at the bottom of each cup/pot.

So far the smaller plants that were potted earliest are showing new growth. And the larger Stapelia in the back left is starting to stand back upright.
Hopefully they do better than before. The roots on almost all of the Stapelia types were either rotted or dried out so I had to clean most of them.

BrendanCS said:Hi @jamesicus

I'm still busy repotting all of my smaller succulents and euphorbias into my semi-hydro setup and I was wondering if you have ever grown these types of cacti in semi-hydroponics?

The smaller is an "old man cactus" and the taller is a "silver torch". They're both really new to me, but I only have a few cactus in my collection and the others I've grown in their soil from wherever I got them and water very little because I'm scared of rotting them. They tend to shrink/thin because I probably don't water enough. These two are "hairy" types and smaller than those other cacti, so I was thinking of putting them in clear pots in my perlite/water on heat pads under my lights since they'd fit. But I know this goes against the rule of cacti not wanting a lot of water.

You are indeed an intrepid experimenter, Brendan! Keep up the good work. Yes I have grown Cephalocereus, Oreocereus, Espostoa, Cleistocactus et al, in accordance with the semi-hydroponic methodology I outline at ……… http://jp29.org/brcult.htm ……… which I just updated. I have found that it is just about impossible for me to over-water my cacti using the soil mix I describe there. Of course, that is here in southern Arizona!

James, great sounds good! I may try the smaller one out first since I'm not sure how they'll react to the water reservoir at the bottom of the pots (no drainage holes)

I'm trying to find tall pots though so that their roots can extend down to the water and not actually sit too much in the water. Hopefully I find two containers for these cacti and they grow well. I'd love to see them flower eventually. The taller one needs more light I think. It has a weird small bump at the top that isn't the same width as the rest. Hopefully direct under the grow lights will help it.

BrendanCS said:James, great sounds good! I may try the smaller one out first since I'm not sure how they'll react to the water reservoir at the bottom of the pots (no drainage holes)

I'm trying to find tall pots though so that their roots can extend down to the water and not actually sit too much in the water. Hopefully I find two containers for these cacti and they grow well. I'd love to see them flower eventually. The taller one needs more light I think. It has a weird small bump at the top that isn't the same width as the rest. Hopefully direct under the grow lights will help it.

You may experience problems with water sitting in the bottom of the containers (no drainage holes) - the long standing adage is: "cacti and succulents hate wet feet!"

I am not sure grow lights will provide enough ultra-violet light to aid in flowering - but I have never grown plants under grow lights and I know there have been great advances in grow-light technology in recent years.

BTW, I fixed the error in the URL link in my previous post.

jamesicus said:

BTW, I fixed the error in the URL link in my previous post.

Thanks for fixing the link

I have a question and a warning...

Question: What is going to hold that Silver Torch up if its planted in straight perlite? Mine is somewhere over 6 feet tall with lots of offsets. It is one heavy plant.

Warning: Oh, wait. This may be a "too late" warning... Don't buy just red and blue lights.

James, good to know. I will try to keep the cacti more on the dry side.

One question I forgot to ask, have you ever measured the soil temperature of your plants on a sunny day in Arizona?

I'm curious what plants kept outside there keep for a soil temp on sunny days compared to here.

Daisy..thanks for the warning. I have T5 HO lights and then a new kind of LED T5 that I'm trying out with those....the pure red+blue LEDs made my eyes/head hurt and the plants looked awful under them.
For the silver torch....I am not sure...I guess I can try to use some larger gravel pieces as a top dressing like it has now, to hold it upright. It is not too big...probably about 13 inches tall.

BrendanCS said: ……… One question I forgot to ask, have you ever measured the soil temperature of your plants on a sunny day in Arizona? ………

No, I have not, Brendan. I used to worry about that - especially during the summer when temperatures often soar to as much as 105F+ under the relentless blazing sunshine here in southern Arizona, and the plastic pots (staged under 30% shade cloth) are often very hot to the touch - but my Brazilian cacti have always flourished, with robust growth, luxuriant spination and bountiful flowers & fruit, so I don't worry about that anymore. At one time I even staged my potted plants inside wooden boxes (as depicted in a photograph at http://jp29.org/brcult.htm) in order to mitigate the effects of the blazing summer sun but I found that was not needed.

James, good to know they can handle the blazing heat there. I saw on your website that you tried the wooden boxes at one point to help block the heat. I worry about that too with the roots on these succulents and cacti. But when I finally got a soil thermometer I learned that the damp perlite in my cuttings box where my succulent cuttings do so well is often 90-100 degrees. It seemed crazy to me that the cuttings and their roots could flourish in that heat (as well as being wet) but they seem to love it. Hopefully they do well in their larger cups now that I've set most of them up in the same scenario.

I just repotted my small "old man" cactus this morning...he didn't have very long roots, but I put him in a taller plastic container of perlite, so hopefully his roots continue growing downward toward the small water reservoir at the bottom.

Thanks again for all your help and tips, one day I hope to have a collection of cacti like you

Just a quick update with some of these stapelias. I repotted two arms that were attached to a main stem I had planted in pure perlite with a small water reservoir st the bottom. They've been in this mix on a heat pad for about a week(perlite temps 85-90F)

The main stem was turning yellow (it was yellow at the tip when I got it) and I decided I didn't want it to spread and saw that these two arms had fresh roots in the cup. So I broke them off and put them in a new container that will stay dry for a few days, so the cuts dry out hopefully.
These arms had no roots of their own when I potted last week.

So far the plants seem to be growing new roots in the pure perlite which for some I can see through the plastic cups.

I had to repot a couple smaller stapelias I had in this system. They had dried out dead center pieces when I potted them last week, and the dried out parts seemed to turn mushy in the heated perlite. So I broke their arms off like I did this larger one. They seem to do best when it's only healthy plants/arms put in this mixture system. Hopefully the healthy looking arms keep growing on their own.

Hello, hope everyone is having a good holiday :)

I thought I'd post some updated pictures on how these small plants are doing. I removed the top layer of tiny gravel that I had put on to keep the perlite in place (and for aesthetics....I still don't like the bright white perlite very much...)

But the gravel was staying too damp around the base stems of each plant and I wanted the water to really only be at the bottom.

Slowly learning that this method seems to only be showing good results on plants that have a good system of roots to begin with. Anything with an already rotting or strange stem seems to rot off quickly in this but if there is a fresh stem, I seem to be able to catch it to try and reroot in my cuttings box.

My cubiformis has new flower buds on each side of it, two groups of flowers seem to be developing faster.


My Rhytidocaulon's are also growing pretty quickly in this, with tons of flower buds at once. I've never had this happen before, usually I'll get one flower or two in my previous soils and they would often dry out and fall off before opening. I'm really pleased to see so many flowers on these dead sticks. They're my favorite plant so I'm glad to see them doing well




This succulent that was doing really badly in soil seems to be coming back to life. It's dropped all of the dried leaves it had on it's lower half and has new growth in the top part-


It seems I have to add about two shot glasses worth of water every 4 days or so. I add Schultz Cactus and Succulent food to the water every three waterings at half strength.

Here are some other plants showing new growth for me, euphorbias, my small dorstenias, a ceropegia and my larger stapelia that is in a giant 12x12" box/pot. The stapelia had gone limp and soft when I had it in the pot of soil it came in. It's the first plant I put in this perlite system so apologies for how messy it looks. Luckily all the stems have stood back up over the last couple of weeks and put off a lot of new growth and tons of white roots down the inside of the pot.
The euphorbia pachypodioides that I thought had died a few weeks ago has become solid again and continues to put out lots of leaves each day so I think it survived the transplant into this new pot system.









This last plant doesn't seem happy. It did not have many roots when I took it out of it's pot of soil a week ago, so I cleaned the dirt and put it in the perlite and added only a tiny bit of water. Now it's leaves have gone red and when I look at it's roots, it has new white ones but everything is really dried out. I think I should have added more water. I'm going to try add water to see if I can save it but most of it's stems are limp and dried out towards the center where they all meet.

Those Dorstenias are looking nice and leafy for this time of year.