The is the top portion of a San Pedro that I cut off and then planted in a separate pot. It has been a few months now and it has not grown a bit. My main concern is it is covered in black spots, is this rot?

Thanks my fellow seekers

The bottom pic is God.

I am no expert on cacti, but that soil appears to have a lot of wood in the mix. I hear that wood is not good for cacti. Have you pulled the cutting up and checked for roots?

I've recently become very interested in cacti, and all the cuttings I've made have rooted and began growing in about a month's time. I let the cuts dry for about 2 weeks, and then plant in soil that is 50/50 mix of potting soil and perlite. I do not water during this period other than a slight mist a week after potting. About a week later I check for roots. So far, I've had great success.

Is it squishy?

I try not to water it, but being that I live in a humid-subtropical southern climate, it keeps raining like 2-3 times a week. I know I am supposed to keep it in full sun with no water to stress it, but at this time of year it just rains so much.

Are you sure you have to put it in full sun ?

I've no experience with cactus yet but i will eventualy and in my mind, iirc, it is better to leave it out of direct sun when it's rooting. I think stressing it is good to increase alkaloids content but not to root.

I definitly could be wrong, so if some cactus pro could chime in, it would be greatly appreciated.


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You do not put cuttings in full sunlight when they are rooting. You do not water cuttings, either. Cuttings don't have roots and cannot tolerate the sun or water.

Once your cutting has a small cluster of roots you can start introducing very small amounts of water to it. This will encourage it to grow as well as search for more water with its roots. But you still do not put it in full sunlight until it has a lot more roots.

Keep your cuttings in indirect light until they have established a decent system of roots. You don't want mulch in your soil mix. Do 50/50 perlite and soil. It's better to err on the part of perlite because I got rot at first as well.

You're probably going to want to dig up your cutting and let it dry out before putting it in a new soil mix with better drainage. This is when you might have to do some surgery if it's rotting down below.

I concur with Nathaniel

Hi DisEmboDied,

From what I can tell, that doesn't look like rot or sunburn, but it sure does look sick.

Does the Mother Plant have the same malady?

Nathaniel is spot on.

Most of the time when a plant is sick, the best way to diagnose the problem is to dig it up and look at the roots or portion below the soil. If you dig it up, take a photo for us. That would help immensely.

Good Luck,
wap

I will warepeople.

never keep a rooting cut in full sun, or starve it of water

You water your rooting cuts? I've learned to definitely not water rooting cuts unless you want it to rot. I do not keep them in sun though. I keep them under a shaded porch in the heat with no water to let them root. Anyways how in the world would a cut absorb water if it's not rooted yet. I don't think it can other than a tiny bit transdermally.

The spots you see I am convinced are some kind of mildew that takes hold below the skin. It forms on my cacti pretty regularly in the summer here. (Hot and steamy here in the deep deep, peninsular south if you get my drift...)

As long as the plant gets adequate air circulation it doesn't seem to affect them too much, but be careful as it can lead to the whole stem scarring over in a corky, bark-like substance. Good drainage is a must so I would ditch the potting soil you've got there. I'm sure they would do well in bare gravel here but haven't actually experimented with that yet. Lots of perlite and bird grit (crushed oyster shells for chickens) has given me good results so far. 1:1:1 ratio of perlite, bird grit and potting soil is the basic mix.

And yeah, don't try to root them in full sun. They can be watered, and in fact it seems to stimulate rooting, but the soil must thoroughly dry out between waterings.

My standard procedure for rooting is to dip the cut end in hormone rooting powder, I leave it laying around in shade for a few days until it is calloused over. Then into some dry, sandy compost, keep it dry until it show signs of growth - especially new light green growth at the growing point. Then gradually introduce water.

The black is reminiscent of a condition called sooty mould, which is not terribly serious, and the plant can grow out of it (it rather looks like this one is).

yes i water rooting cuts, especially if its 100* out. the soil goes bone dry in a couple days...

I dont rec'd rooting hormone on anything that might be consumed

I see. I keep my rooting trichs in plastic pots. It's super dry and hot out here in the summer and they've been rooting great in the bone dry soil. I'm sure the plastic pot keeps any moisture locked in there though. If it starts taking a long time I will let a tiny bit of water soak up from the drain pan into the soil, but only enough to wet the bottom layer. It seems that the plant senses it and tries hard to stretch it's roots down into the ground. In my experience it's always been dry conditions that stimulate rooting, but it could be vise versa sometimes too I guess. The only reason I do not water cuttings now is because every time I've done that they've rotted. Lost a couple awesome plants that way.

Good news, there are nice roots!

My main concern was the black spots...

Hopefully it will recover then - good luck with it.

Those spots! I get those spots on some cacti. MS Smith (whose flickr account is something you want to see) has some pics of this too. Doesn't seem to be sickness. Does not directly lead to rot but may be an indicator of an issue that could.

The funny looking guy in the back to the left has the black stuff on the underside of the pup.

I think he had some suspected causes on a post on the nook, but It was all inconclusive.

I have a couple theories too based on what I gleaned from other posts and my own cacti....but nothing to back it up.

I'm fairly sure humidity and heat combined is factor. I had some cacti at a friends place that got this pretty bad starting near the base and working up 6-8 inches. I moved them to a new place, repotted them and while it never "healed". It totally stopped forming and didn't appear on any other cacti in that new location. Could have been the repotting, could have been the move. The 2nd location had better breeze.

Now, I've got everything in one yard, I'm here everyday. I've got a few zones... Full sun, shady, in between, side of the house blah blah. Trying to find the sweet spot, but I've got to leave them alone long enough to see what's what..... I will have to report back after a few seasons.

So, all is well
UNTIL , I've noticed now, on a 3 foot tall Torre Pedro that this black speckling is starting to show only near the top. I don't know, nothing else seems effected, and I've never seem this black stuff that high . My collection is all prettying young. Besides a bigger Cactus Kate PC, nothing is much taller the 3 feet. Most of the cool clones under my care are less than 2 ft and even my 8inchish seedlings aren't showing this black stuff in the same spot of the yard. It has been hot and rainy allot, so it may be that.

I'm keeping a watchfull eye, but it could even be some soil content, ph, fungus.... I don't know. It won't scrape off, so I believe its under the skin. I can't say for sure that I've pealed one with this, but when I think back, I truly must have. I do not recall seeing black under the skin. I think I would remember, so maybe it's inside the stoma of the waxy skin, like mold, mildew, fungus in the tiny pores.

No way in hell I'm butchering Torre's tip to examine the blackness, so that experiment will have to wait a while, at least till a base pup shows.

This appears to be a condition called sooty mould. It is associated with a number of factors, one of which is, surprisingly, the deposition of honeydew on the plant. This is a sugary secretion produced by aphids, whiteflies and spine mealies.
As I mentioned earlier, the plant can grow out of it when the root cause goes away.