Interesting Grafting Articles

[b54red]

Originally Posted by rwsacto

Bill,

Thank you for the detailed grafting instructions. I am just starting germination and will be using rootstock shoots held over from last year, including supernatural and RST-04-106T. I rooted the tops from last year and kept them in pots in the garage with a couple of CFL lights.

In your instructions, after grafting, are you covering the graft (and clip) with DE?

Thanks,
Rick

Rick, I am not covering the graft and clip with DE. I sometimes add the dry DE up almost to the bottom of the clip if I have a graft very low down on the rootstock stem.

Bill

[b54red]

I did another batch of grafts the other day and unlike my first two this one looks like it will have a lot of failures and I don't have a clue why. This is the most frustrating thing about grafting. I'm beginning to wonder if it has something to do with the phases of the moon or something because I use the same technique with all my grafting now but sometimes I will have a batch that doesn't take well.

Bill

[aclum]

Hi Bill,

I "feel your pain" (or frustration in this case). I think this unpredictability is at the root of my grafting obsession. Figuring out how to get consistent results with so many variables is like a challenge or problem to solve or fun game! (If Delerium's reading this, he's probably banging his head against the wall by now ).

Reading new (and/or re-reading old) grafting articles, I'm beginning to conclude that water stress is the critical factor with other variables of less importance.

(Hey! Just proof reading this post and re-reading yours.....maybe you're right and phases of the moon do make a difference - you know....tides and all that . Maybe you need to start keeping track of that factor) anyway, back to my original post after that brilliant insight ...

There's some good stuff in this 2013 Thesis on grafting from KSU:

https://krex.k-state.edu/dspace/bits...pdf?sequence=1

It's copyrighted so I don't want to quote too much but here are a couple of short excerpts from the Abstract (much more detail in the thesis itself, of course):

... many have difficulty with propagation due to water stress in the scion post-grafting and/or high temperatures within healing chambers...

... Five healing chambers designs were evaluated, and no

significant effects of treatment design were observed upon grafted seedling survival. Plants grafted with no chamber had success rates of 81% to 91%...

... Partial leaf removal may be recommended as a way to reduce water stress in the plant, and could potentially be a way to simplify the grafting process for small-scale producers....

In some of the case studies plants with the humidifier were a bit more successful but generally not by much and not always.

From this "article" I've linked to previously on lighting:

http://www.vegetablegrafting.org/wp/wp-content/uploads/2015/01/hu-2-usda-scri-grafting-symposium-poster-dec-14.pdf

it appears that post-grafting lighting is not critical and a level of about 135 micromoles/meter square/second (or 4 5T HO bulbs 15-5/8" above the plants) is fine. So one could theoretically just eliminate the whole past-grafting routine going from total dark to shaded to open which seems to have been the usual or typical procedure. I'll need to check, but I think the 135 level mentioned might just be the equivalent of ambient indoor light or windowsill.

Just speaking for myself here (as an experiment), I think I can skip the healing chamber totally, leave the seedlings under light until I graft, then let them heal at the approx. 135 micromole/meter squared/sec light level. Doing all this at our "warmish" room temp of about 77 and humidity of 35%.

I plan to trim most of the scion leaves and get a good clean graft at matching stem diameters.

The remaining variables would be the soil medium and water treatment before grafting. I'll be going with the wonder soil although DE could be better (I haven't really had any problems with damp-off in our climate using any soil medium). I'll moisten the WS a few hours before and let it drain well before planting.

In Delerium's no-root grafting, he soaked his cut scion and rootstock pieces in water for about 5-10 minutes prior to grafting. This apparently eliminates a lot of the immediate post-grafting water stress. I think I'll try doing the same, even if I keep a bit of root attached to the RS - which I haven't decided on yet.

Anyway, that's my plan for the moment. I've probably got about a week before I actually start grafting so plenty of time to change my mind!

Anne

[b54red]

I do find that keeping the newly grafted plants in the higher humidity of the healing chamber is a real benefit especially for the first few days but when I graft during times of heavy rain and near 100% humidity I find myself opening the healing chamber completely the next day without the sudden wilting that usually would result from leaving the lid off so soon.

I don't usually pull off all the roots but I do usually remove the bulk of them just before I graft. I found this worked better for me than completely removing the roots. It allows some water uptake but not so much as to separate the new graft.

I find that watering the scions well a few hours before grafting is sufficient. The system I use means the scion is only cut off and then attached within a time period of less than a minute before it is grafted and put in the healing chamber so there is no drying out of the cuts since the grafting is done within seconds.

Bill