Seems to me that plastic cling wrap could have a use here
Gotcha. I didn’t take the time to fully read prior to answering. Guess I’ve had the luxury to not really ever having to deal with dried out wood. I’d guess if it looked dry soaking the night prior would be beneficial, but other wise normal looking wood i wouldn’t bother. My biggest problem with scion wood is that I’ve received some that looks like it was cut too late and had swollen buds.
I’ve finished my little experiment on rewetting dried out scions. 28 each of fig and peach scions were allowed to dry for 4 days setting on my kitchen counter. Then submerged for 3 days in water and weighed at various intervals to see how rapidly they dried and then rewet. What follows is the weight of all 28 cuttings. Weight after wetting started is corrected for the small amount of surface water that remained on the cuttings after they drained for 30 seconds.
time…Figs…peaches
start…187 g…84g
1 day drying…172…73
2days drying…158…65
3 days drying…146…60
4 days drying…140…58
15 min wetting…141…59
1 hr wetting…143…61
3 hr wetting…156…66
6 hrs wetting…166…68
12 hrs wetting…172…70
1 day wetting…184…72
1.5 days wetting…191…75
2 days wetting…194…76
3 days wetting…199…79
The cuttings were shriveled looking after two days so this was severe drying. It took a considerable period of being submerged to regain the water lost. The peaches never quite did regain all the loss. The figs gained it all back and more probably because they were at least somewhat freeze damaged and dried out when cut.
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Definitely a cool experiment. On another note something more I would like to know about is if water is replacing say sap, then is the scion less likely to do well if more water is added than originally contained…
I learned what I know from one man that was considered to be the best conifer grafter in the United States (deceased.) He would tell me to never submerge for more than 1/2 hour maybe 45 minutes for either conifers or deciduous. If that didn’t do the trick… to throw them away!
Our normal rehydrating was 15 minutes and if the tissue when snipped off a three or so hours after didn’t look healthy (muddy green or worse looking “brown”) to immediately pitch them. If they were somewhat ‘decent’ green but appear they need more water than do another 15 minutes maybe 30. After that and waiting three hours prior to grafting them they weren’t ship shape, toss them.
I tell ya the guy was a master grafter. He grafted it all and told explanations that made sense when something didn’t graft successfully. Of course since a lot of us have been grafting we know it all starts with healthy scions and healthy rootstocks and that aside, good to great roots.
----------Edit more questions/concerns I’m wondering:
And could it be said that water is replacing areas between cells where cells have died especially the cells making up the cortex. Where or what exactly is the water replacing?
Bark is being re-hydrated… how much does that account for losses???
These types of questions…
Dax
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Steven,
Thanks for conducting this test- there should be a category stronger than “like” for posts like that, maybe something users earn themselves by receiving likes or at a set rate of 1 per week/month.
I had initially figured that soaking wouldn’t make much difference, but your data leaves me thinking that this is a very interesting possibility for improving take rate in things which can be challenging (peaches and maybe grapes).
A couple other avenues for investigation:
1.) What is the usual water loss in “normal” stored scionwood?
Test: I always have extra wood of some varieties that I cut, but don’t end up sending out. I’ll wait until grafting season and try the hydrating trick to see how much water can be added in 3 days. It looks like peach gets back to ~94%, so I should be able to back into how much water was lost, by how much the weight increases by (plus a bit, as it is only getting back to 90-95%). It could also be interesting to look at how much is lost from other types of wood. For instance, I’ve seen a lot of bad persimmon wood- maybe it dries out quicker? On the other hand, maybe apples and pears tend to hold onto their water? An interesting topic to explore.
2.) How much does being re-hydrated help in terms to take rate? Does it have an impact on post-grafting vigor? Some of Dax’s questions could come into play here.
Test: Graft both treated and untreated wood to the same established rootstock. Measure the take rate and the initial season’s growth from both versions. I often make backups anyways, so this just calls for a bit more prep and record keeping. This one could be tricky to get enough data for- there are a lot of other factors which impact take rates and growth.
I do have a couple questions about how you conducted the test.
1.) In the initial post, you said that you were separating the 28 scions into groups of 4 and re-hydrating each group for a different time. Is this how you eventually did it, or did you re-hydrate all of them and just put them back in the water after measuring? If you kept to the original description, how did you make sure that all the groups weighted the same amount?
2.) When re-hydrating, did you submerge the entire stick, or just the end, relying on capillary action to pull the water in?
3.) What temperature were the scions at, during the re-hydration process? For the initial test, you could do it at room temp, but if you were actually planning to use them in grafting, I imagine you;'d want to do it in a fridge, putting the whole thing in a plastic bag.
Thanks for the great post!
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Bob thank you for your interest and support.
I agree with the further testing you suggest. I thought about that but didn’t have any left over scions that I thought might be somewhat dry. If I do have some down the road, esp figs, I’ll hydrate and weigh to see if they really were dry.
I changed the test to weighing all cuttings as a group. At first wetting I weighed to get final dry weight. Then dipped them in water fully submerged, pulled out immediately, let them drain 30 seconds and reweighed. That was a 2-4 g difference and was used to correct for surface water on all following weighing.
The cuttings were fully submerged and at room temperature between each weighing.
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Steven,
That’s just half the experiment - 
The other half is to see if the re-hydrated scions take.
Don’t ya just love it when you give a hand and they take an arm?
Mike
Yes but I didn’t have time or need for that. Takes are all that counts.
For those visual folks like me. Nice data!
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How about using distilled water ?
Vs.
well / city / ground water?
The difference in osmotic potential could make a significant difference .? ?
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It would have to be very hard/salty water to make any difference IMO. Distilled water would be ideal but not something to be concerned about. I used well water for the test shown and it’s full of carbonates.
Looks very nice…!!
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Thanks! This was a very useful thread in my search to learn something about grafting.
I realize that If I want fruit from my 10 year old outdoor Magness pear I’ll need to graft on some pollinizer branches. I’ll have it figured out by next winter, thanks to the great information on this forum.
I’m looking forward to this year in the screenhouse orchard. I’ll have to extend the screenhouse with more trees coming - apples (Honeycrisp and Goldrush), pears (Harrow Sweet & Shenandoah), a cherry (Lapin), and an Asian Persimmon (Fugu). The screen will go back up after pollination/the last snow, which ever is later. I know you recommend 15-9-12 or 16-8-24 for the potted trees but should I renew the micronutrients, too?
I had mushrooms in a couple pots. I added mycorrhizae to the media, so maybe that’s the source. They weren’t honey mushrooms, so probably OK.
Hope your pecans thawed, your nectarines don’t freeze and that 2019 is a high Brix year.
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Micronutrients haven’t been a concern of mine. I just use some MG complete water soluable. That has all the micros. In fact my only issue with micros has been an excess on Manganese. Don’t overdo the micros.