I degraft cactus around winter solstice and keep in dry condition until warming up in Sptember.
It is not cactus growing season currently but I can do quite many preparation for coming spring.
The attached photo is degrafted cactus with a short stock.

1. Discocactus heptacanthus v griseus
Sowed seeds on 31/08/2006, grafted very young seedlings
Current diameter is around 12 cm.


2. Thelocactus heterochromus f longispinus
Sowed seeds on 31/08/2001, grafted very young seedlings
Current diameter is around 15 cm

Interesting... so, does the shortened stock develop roots, or does it shrivel and the scion produce roots of its own?

Lachy

Plants will be upside down after dried stock completely. Plants will be sit on empty black plastic pots.
Roots (aerial roots) will come out from the short stock before September.
The short stock will be buried in potting mix. Roots will never be developped from plants (scions)
You have to remove all areole on the short stock to prevent coming up pups from the stock.
This method is not actual degrafting. The character of grafted plant will be remained.

If you remained a short stock of pereskiopsis or a short vascular bandle of Hylocereus, roots come out from the short stock or the short vascular bandle but roots come out scion later and the stock will die eventually.

Hanazono

DEAR Hanazono
why you put them upsidedown? why did you cut the stock?

astro90

I use 3 way of degraftings to meet the purpose.
1. Normal degrafting (removing grafting stock completely)
2. Degrafting with a short vascular bundles of grafting stock (Hylocereus stock)
3. Degrafting with a short grafting stock (as shown attached photo)

In case of No. 2, roots come out from the vascular bundles initially but roots come out from the scion later.
Some Ariocarpus eg fissuratus is difficult to stop liquid from cutting face and rotting out during rooting.
The way of No. 2 is usefull method for the situation.

In case of No. 3, root come out from the short stock only, never come out from the scion.
You can keep grafted characters, strong spines and many flowers etc in this case.

The photo is showing case No. 3, drying process of cutting faces on grafting stocks and so they are upsidedown.
When cutting faces were dried completely, plants are turned over, stocks are in empty black plastic pots.
I cut stocks in autumn and keep until spring. Air-roots come out from short stocks in empty black plastic pots.

Hanazono

Gracias for complete description.