Preventing Pereskiopsis sap overflow

[Driller64]

A problem I am having with grafting to Pereskiopsis is unless the soil is almost bone dry the sap usually overflows and causes the graft to fail. I tried leaving pressure on the graft then moving it to the humidity chamber but the peresk was dried out by morning (I grafted at noon the previous day). What could be the problem? I really can't afford to waste seedlings.

[Hanazono]

Although I use a different grafting method, I have never experience the overflow of Pereskiopsis sap.

I use a 15 cm length of offset cuttings for the stock.
The cuttings are set in wet-potting mix and kept in a wet-box for 3~4 days.
Water is filled in bottom of the wet-box.

Since the stock is set just 3~4 days in wet-potting mix no roots are developed when scions are grafted.
No sap will be running because the stock has no roots.

Grafted scions are returned into the wet-box and kept for 10 days for the grafting process.
After 14 days from the initial setting, roots of stocks start to develop.

You may try wet-potting mix with no rooted stock grafting to minimize your problem.

[Driller64]

I still need help with this

[HP22B]

Are most of your stocks clones? Perhaps just a very sappy family. I've never experienced this problem.

[Driller64]

I have Pereskiopsis from two sources as far as I can remember, from Samuel Rodriguez and an old plant from ebay. I'm not sure which of more clone I have more of since I never bothered to keep track of it, but I guess I will have to eliminate stock plants i'm sure are from the old plant if that is the issue.

[Driller64]

I believe I have found a solution to this problem, which is to not spray water inside of the humidity chamber or only give one spritz to it and leave it that way for the first 24 hours at least. That way there is just enough humidity to keep the tissues from drying out but not enough to draw sap.