Offset?

[zpeckler]

So I was unpotting my Gymnocalasium horstii and underneath the soil line was this BIZARRE growth. The thing is growing off an an areole and has areoles itself. It was growing straight downward from the main plant's body. It's firm and looks just like the body of the plant—down to it having 5 ribs just like the plant does above ground.

This looks like an offset, but I thought G. horstii had a solitary body. Obviously I could be wrong on this because my background knowledge of Gymnos is paper thin, but I've never heard of hostii being polycephalic.

EDIT: Well, the Wikipedia article for G. horstii says they "offset over time." I guess I answered my own question.

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[Steve Johnson]

Yes, but an offset growing upside down? That's a new one.

[zpeckler]

Yes, but an offset growing upside down? That's a new one.

I know, right?! It's growing straight downward. I wonder what the odds are that it'll right itself. I don't want it to just continue to grow down into the substrate, sucking away resources from the main plant.

[Steve Johnson]

I know, right?! It's growing straight downward. I wonder what the odds are that it'll right itself. I don't want it to just continue to grow down into the substrate, sucking away resources from the main plant.

Agreed, and I'd also be concerned about the offset's lack of chlorophyll. Would you be in for a chop-chop, then try to root it just to see what happens? If you do, be sure to give the exposed surfaces a liberal dusting of sulfur powder, give them enough time to form calluses, and repot. If you don't have any experience rooting offsets and cuttings, I can guide you.

[anttisepp]

G horstii is an easy plant, gives offsets regulary. This one had to grow downward because of bad place of origin. Cut away, let it dry a week and plant as a common cactus, first time protect from direct sun.

[greenknight]

It lacks chlorophyll because it wasn't getting any light. It should do fine, but be careful about sunburn until it's fully greened up.

[zpeckler]

Thanks everyone.

I'll cut it off and let it root. I've got another cutting I'm waiting to callous at the moment, so that won't be too much trouble. It's held on to the main body by a really thin attachment point, so the wounds on the plant and offset should heal without too much trouble. I've got sulfur powder and plenty of extra pots on hand.

[Steve Johnson]

I'll cut it off and let it root. I've got another cutting I'm waiting to callous at the moment, so that won't be too much trouble. It's held on to the main body by a really thin attachment point, so the wounds on the plant and offset should heal without too much trouble. I've got sulfur powder and plenty of extra pots on hand.

From a "Good idea or bad idea?" thread I started in September 2021:

Before I do the chop-chop next year, I'll research the various products to see if there's one in particular that stands out from the rest. Or maybe they're all the same -- any thoughts on this, Mike?

I'm pretty sure I read somewhere that auxins for succulents have close to no effect on rooting. I have never bothered. I do use sulphur to dust large cuts. The trick is to properly season the cut. I normally sit the plant upside down in an airy shed until the wound is quite hard and the plant body dehydrated a bit then sit in a styrofoam cutting box on dry sand with a touch of humus in a warm slightly shaded spot. Lightly misting now and then seems to stimulate rooting, then when the roots have broken, a good soak followed by complete drying and repeat the cycle. I find it's good to let the plant root in the box for a whole season before lifting.

Instead of Mike's rooting box, you can do it with a pot. I wouldn't go with any old sand, so I'll recommend this potting sand from Amazon:

https://www.amazon.com/Original-Ingredi ... r=8-2&th=1

A 1" layer of potting sand over your substrate of choice. If I'm reading Mike right, I believe that he's mixing the sand with a touch of humus, not using the humus as a substrate. What kind of humus it should be, I haven't a clue. As for what he said about timing, yes -- let your offset root in the pot for a whole growing season, then lift it out in spring 2025. If the roots have broken through into the substrate before then, you'll have a robust root system waiting for you when you repot.

[zpeckler]

Well, I sliced off the errant offset this afternoon. It was held onto the main plant by a wispy little stalk that was probably only about 2mm wide. Dusted with sulfur. It's such a small little wound. I've got no worries about it healing over nicely.

Here's the funny news... the offset already has roots! I couldn't tell until I cut it away, but a little clump of roots was coming out of the offset and not the main plant. I guess that increases the chances of survival. I'll wait a week or so and then plant it. I'll keep it out of the sun until it shows some growth with chlorophyll.

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[Steve Johnson]

Very good! Overnight lows in my part of L.A. are slowly creeping up into the low 50s, although not consistent enough for deep watering until later this month. Your overnights aren't there yet, so I'm guessing early to mid-April before you'll be ready. When you are, the offset with roots means that you can also start fertilizing it. Don't be surprised if you see it greening up a bit more quickly than you might expect -- the fert regimen you and I are following will certainly help.

[greenknight]

No surprise - offsets sometime grow roots even when they're above the soil line, those that are below the soil usually produce their own roots. That thing's ready to grow - I'll bet it starts showing some green even before you plant it.