pete666 wrote:That makes sense. I would like to improve the probability of success, so I will ask differently :
I have about 30 various plants of trichocereus and I recognize one as the most potent one. So I would like to use it as a source for scions and the rest of the cactuses as a stock. What would be the best strategy? Using middle cuts, or grafting pups? Or is the whole idea wrong?
There are many possibilities here depending on skill level.
The most you could make would be accomplished by making areole grafts.
However, the exact method, I would choose would be dependent on total length and girth of the specimen as well as the chosen stock.
My preferred stock for a large specimen would be a large pachanoi. The larger the better, but you can graft seedlings a few days old to a very old large pachanoi as well.
I will explain a bit further though.
If your specimen is 4 or so inches in diameter I would choose a stock that is a bit bigger in diameter to offset your graft.
Offsetting intentionally is much better than trying to get it square on just in case your growth ring happens to fit perfectly inside or outside the growth ring of your stock causing your graft to fail.
If you have a fairly large specimen, make a nice straight cut and ensure there are no ridges. Ruffles have ridges... not scions.
Now, with a woody specimen it is even more important to be fast, so I suggest you have your stock precut, but leave the top in place while you adjust fire on your scion.
Your middle piece scion, also must be cut smooth without ridges if you want to have an easier go of it. Now, you may choose to bevel the edges of both the stock and scion now if you plan on leaving your specimens outdoors unprotected from rain while they graft.
Or you may forego the beveling till your graft has taken. The older the scion bottom and the thicker it is the more I suggest beveling it even if just a smidgen as the green outer skin can become quite tough on either and actually push up and away causing the union to be imperfect. Never mind collecting water.
Now, many might use pantyhose to pull a large graft tight, string, tape, etc. I've done many of those methods. My preferred method is to use many methods however.
Let me explain, you have a very rare specimen in your eyes or at least very valuable. You don't want the union to be just barely on or to fail for any reason.
So utilize the benefit of string which allows you to pull down snuggly over each side while still allowing you to peer through your graft union with the help of a penlight. Tighten down exactly as you would tighten down a car tire (think sequence).
Now, understand string can loosen as the graft dries. What was once snug is now loose. Fix that with some self-adhesive coban. Pulling down gently, but snuggly over the graft top down to the sides in an "X" pattern will secure your graft should the string loosen. Next, add a band of self-adhesive coban around the graft union itself. This will ensure humidity is increased while still allowing the graft union to breath.
Understanding that the purpose is to create many, you may seek to graft just a small piece of the tip onto something for your own use or keepsake. This will promote pupping of your middle section.
Allow those pups to grow to 2-4 inches. Remove those pups and graft. Now, the longer you allow those pups to grow before removing them the stronger the response will be to begin pupping again. So, there is always a give and take with grafting.
I try to leave 2 areoles in height for grafts at the bare minimum with the understanding that I may have to use
keiki, if I want to really expedite matters.
Now, if your specimen is very small... I might use parafilm in conjunction with self-adhesive coban.
When I graft you graft we graft