Hey all,
  What is the secret to getting really nice healthy calluses to form on the bottom of cuttings?
  From what I've experienced, the cuttings that have really nice calluses before rooting (or that develop really nice calluses while rooting) either sprout really nice roots from the calluses, or the calluses stay nice and firm.  Cuttings that don't have really nice calluses seem to be more inclined to decay at the end even if they've rooted elsewhere on the cutting.
 What is the secret to promoting nice calluses?
Jim

My response would be correct temperature and plentiful water in the cutting but not constantly wet on the exterior. I'm going to be certain that my next cuttings are fully hydrated as they come out of storage and before increasing temperature to induce rooting. That callus tissue is mostly water. 

Steve, how do you hydrate the cuttings coming out of storage?

See this thread about hydrating dried cuttings.

http://figs4funforum.websitetoolbox.com/post/hot-water-rescue-6816776?highlight=hot+water+rescue&pid=1282376531#post1282376531

What seems to work really well for me is snipping a little bit off the cutting before soaking, and then using a razor blade to shave the bottom of the cutting to within 1/8" of a node. It makes a cleaner cut. The wood fibers don't get crushed by this whittling action.

...what jenn42 said. Lol

Give them shovels and put them to work! Just kidding.

Hi needaclone,
What is the secret to not have a nice callus ?

Well, I would say it is "getting" the cutting to rot .

So just avoid the cutting to rot and you'll get nice callus .
As you probably know, I put them cuttings straight in 1 or 2 liters (1/4 to 1/2 gallon) pots full of nursery compost ... So don't ask me about my calluses ... I can't see them .
I see them grow and become trees . I guess that means that they callused as nicely as could be .

IMO, the best way to get a nice callus is to take cuttings in July and root them right away.
I have July cuttings that traveled 2000km in my car and are rooted and growing nicely .

Thanks jdsfrance,
  Rooting in summer direct to pot is certainly a good option if it is available -- I've had good success that way, too.  No need to overcomplicate things if the timing is right!
  If the timing is not right, that's a different story I guess.  I've had cuttings develop roots all over the stems but still had rotting at the bottom.   I've had cuttings develop roots all over the stems while the bottoms just stayed "normal"--no rot and no callus.  I've had cuttings develop nice calluses on the bottom but the first roots sprung out all over.  Finally, I've had cuttings callus up really well at the bottom and then have nice strong roots burst forth from the callused area.  Those last two options are what I'm shooting for, where I'm sure the bottom cuts are nice and healthy.
Jim 
 
 

Jim,
Here's what you do, and this is strictly out of my experience with treating and prepping the cuttings before rooting.

- First of all, make the cut close to the note where inside of the cutting is solid.
- Deep the cut end or ends in melted Paraffin, about 1/8 inch or 1/4 inch beep.
- Zip-lock it and refrigerate it for 2-3 weeks, this allows the cutting to develop calluses and same time to regulate the moisture throughout the cuttings evenly.
- Then you can root them the way you want. If you do it this way, you'll never lose a cutting to rot.

Good luck :)