Tuesday, April 30, 2013

Is it time to graft pecans?

    Yesterday and today, afternoon temperatures climbed into the low 80's (F). It finally feels like spring and I'm getting the urge to graft. But wait,  the weatherman is promising us another blast of cold temperatures by the end of the week.  Friday morning's low is predicted to drop to 34 F. Should I wait a while longer before grafting?

     This year's spring-temperature roller-coaster has got a lot of people wondering just how they can determine the best time for grafting. This morning I walked out to a row of seedling pecans to check on their readiness for grafting. The photo above shows you just 5 of the trees I found (click on photo to enlarge). These trees are all Kanza seedlings so the wide variation in bud development caught me by surprise. As I have mentioned in a previous post, it seems like this year's cool spring has stretched out the pecan bud development process.
     Of the trees pictured above, trees A and D are ready to graft by using the 3-flap graft or bark graft. Trees B and E can be grafted with a 3-flap but they have not progressed far enough for a bark graft. It too early to graft tree C.  My personal preference is to wait a little bit longer before grafting. When I go to the field, I want to be able to graft every tree in the row and have all grafting technique options available to me on each tree. This way I can choose the best method for grafting depending on the size of my stock tree and the diameter of the available scions.
    If you are wondering if cold temperatures will reduce grafting success, the answer is no. The scion will just hang out on top of the stock during a cold snap just like it was still in the crisper of the refrigerator. Once warm temperatures return, the callusing process will begin and the graft will progress normally.  On the other extreme, temperatures above 90 F can "cook" a recently applied graft and cause graft failure.