Details about grape grafting

[Peterl3233]

I do hardwood grafting of grapes but with variable results. I'm looking to improve my technique. I have good rootstock and good budstock and I think my graft union and waxing is good but often the bud opens up before the roots come and then the shoot fails. If I apply bottom heat only, the roots come but the graft does not callus properly. Just wondering how others do this .. ?

Peter

[silver_creek]

After grafting, the sticks need to callus at 80degrees F for 3 weeks. (Bury them in a sterile moist medium.) Then stick the callused grafts into medium and apply bottom heat to encourage rooting.

[Peterl3233]

Originally Posted by silver_creek

After grafting, the sticks need to callus at 80degrees F for 3 weeks. (Bury them in a sterile moist medium.) Then stick the callused grafts into medium and apply bottom heat to encourage rooting.

Hi .. thanks for your reply of a couple years ago .. well I'm back at it and preparing for 2009. Here is the issue: When I put them in the sterile medium for 3 weeks the buds still sprout out and i get too much shoot growth before the roots come out. The result is usually a dead vine. Maybe it is an issue of timing or temperature. This year I have it in my mind to callous them for a shorter period ... actually watch them and when I see reasonable callous growth to move them to small pots with bottom heat only in a cool room.

Another thought is this ... I heard that if the primary bud opens, I could cut off the shoot and wax it again, so as to keep the moisture in while the roots form and rely on the secondary bud. I think this is what the commercial producers do but I'm not really sure.

I appreciate any comments or suggestions of course ... I am trying to populate another row of Pinotage grapes this year so I'll take on about 400 grafts .. if I can gain the confidence that I won't screw up again ..

Peter

[silver_creek]

We don't wax until they come out of the callusing room. At that time, any primary shoots are taken off, the bud/graft waxed and the graft stuck in potting medium (add small amounts of time/temp release fertilizer to this). We then put them on 75oF bottom heat until they push. Too much temp difference between the roots and tops can also cause failure; we pull remay over the flats to retain heat around the buds. This year, a further advance in our system will be to water with warm water instead of cold. We do about 35,000 grafts each year and would like to push our success rate up to 80%, so we continue to try to improve our system.

[joelfisch]

I would be grateful for suggestions on this topic, having had the same problems noted in the thread; early bud break, insufficient rooting. I have a thermo controlled callusing sweatbox that uses heating cable on the bottom - I use fresh, coarse wood shavings as a rooting medium, since its easier to avoid water-logging. No great success to date, but still trying.

-you suggest waxing AFTER callusing - i thought waxing was needed to physically support the graft, which is often a bit loose. Would you suggest putting in a staple on the graft union if its not tight?
I found and like this grafting pliers http://www.grafting-tool.com/magento...ting-tool.html after being dissatisfied with the 3GT Pliers.

my plan this year will be to:
- callus in the hot box for 3 weeks with the sticks lying down.
- remove from box, repack in moist shavings, but with stick standing up and just the bud peeking out
-leave the hot box open, to get some cold on the top and inhibit budding and place the thermostat in the rooting zone. Israel winters are not freezing, and even night temps are around 15C
-Hang a fluorescent light above the box so that when buds open, they can start photosynthesis
-move from the wood shaving medium to potting only where there is decent leaf and root growth and its relatively temperate (should be late march)

I would be grateful for any suggestions here.