Looking to Graft an Apple "Frankentree" but Have Some Questions

So I'm short on space and I have this established crabapple (actually a 35+ year old rootstock from a box-store tree that didn't thrive and was cut off at the ground, but kept coming back and being scraggly and sad, so I moved it and let it go to see what I got).  I've been meaning to start collecting scion wood and grafting onto it, but wanted to wait until it bore fruit to get a feel for the tree.

Finally, last year I got like 15lbs of crab apples (nothing to write home about; sour & astringent but made decent jelly at least), so now I can decide how I want to shape the tree and what I want to graft to it.

BUT!!! I had a thought.  If I were to air layer some of the branches, I'll get a bunch of really good rootstocks and I can make more apple trees to give away/ trade/ sell.  I mean, I've never done it it before, but it's worth a shot, right?

So my questions:

Should I put off the beginning of my grafting project another year and let the tree focus on making roots on the air layered branches?  Or can I do both at the same time, as long as I only do one or two grafts and one or two air layers?

How many air layers can I do on a relatively young, healthy tree?  No grafts, just trying to maximize rootstock production.  Even though the rootstock is old, the aboveground part is only 5 or 6 years old.  Is there some kind of ratio of branches, like one air layer for every 10 branches, or is it a vibes thing?

Conversely, how many grafts can I do on one mature tree per year (no air layering)?  If I do spring grafting, can I do bud grafting in the fall of the same year?

As you can tell, I'm kind of a grafting noob; I've only done it twice so far (peach to apricot, apricot to apricot), though like 80% of what I did took and is still healthy after a few years, so I think I have the basics down.

Anyway, and advice would be appreciated.  Thanks!!

Can't help you with air layering. But grafting is very easy. Especially drill bit grafting on established trees. I have even seen folks save rare and very small twigs using modified drilling where they use a small sharpened pipe to pop up a plug. Which they drill precisely to insert the tiny Twig in to match Cambrian. Then pop the drilled plug back in the tree. And paint them with graft sealer.

I have personally seen one tree with 84 other grafts. I heard it claimed 120 on a single tree.

S Tonin wrote:Should I put off the beginning of my grafting project another year and let the tree focus on making roots on the air layered branches?  Or can I do both at the same time, as long as I only do one or two grafts and one or two air layers?

You can do as many as you want of both, preferably grafts on pencil sized wood to minimize shock to the tree that can happen with removing more wood which would delay fruiting.

How many air layers can I do on a relatively young, healthy tree?  No grafts, just trying to maximize rootstock production.  Even though the rootstock is old, the aboveground part is only 5 or 6 years old.  Is there some kind of ratio of branches, like one air layer for every 10 branches, or is it a vibes thing?

The only limiting factor really is if the branch can hold up the weight of the air layer from the soil in the air layer, but in your case you could really let the branch go all the way to the ground and then layer it in the soil also if the branch is long enough.

Conversely, how many grafts can I do on one mature tree per year (no air layering)?  If I do spring grafting, can I do bud grafting in the fall of the same year?

As many as you want. Yes you can do both in the year.

As you can tell, I'm kind of a grafting noob; I've only done it twice so far (peach to apricot, apricot to apricot), though like 80% of what I did took and is still healthy after a few years, so I think I have the basics down.

I have two apple trees and one pear tree with multiple grafted varieties and it's been really fun seeing all of the varieties growing beside one another! Hope yours turn out well!

Thank you Steve!  Now I just need to get up the courage to approach some of the people around here and ask them if I can take a few cuttings off their trees.  Once you really start looking, it's amazing how many neglected apple trees are still around, sad and forgotten.