Don’t thin apricot fruit in order to increase fruit size

The standard advice from the experts once again doesn’t align with my experience. This time it relates to the idea that thinning fruit will lead to larger fruit. From the horse’s mouth: “Thinning immature fruit at the appropriate time allows each remaining fruit to develop to its maximum size.”

Why? “Excessive fruit compete with each other for carbohydrates and remain small.”

Therefore, “All stone fruits (peaches, apricots, nectarines, cherries, plums, etc. ) require thinning.”

The horse is the University of California publication “Fruit Trees: Thinning Young Fruit.”

Until I learn otherwise, I follow the advice of the experts. So last year I thinned my apricot fruit precisely as they advised. The harvest was very satisfactory. But this year, just as an experiment, I didn’t thin. I wanted to see if the fruit would end up smaller at harvest time. The tree set a ton of fruit, more fruit than last year, but still I left them all, except for some fruit that weighed down the ends of a couple of thin branches and threatened to break them. The result? More fruit than my family and friends could eat, so many that I dried dozens of them, and yet they were the same size as last year. There was no difference in the size of the fruit at all.

Sun-drying apricots we couldn't eat fresh.

Sun-drying apricots we couldn’t eat fresh.

My conclusion is that while there are other good reasons to thin fruit, the goal of increasing fruit size is not one of them — for Blenheim apricots anyway.

Thin fruit if they might break a small branch, thin fruit that are diseased or damaged, thin fruit that are too exposed to the sun, for example. But don’t thin fruit thinking that it is the way for “each remaining fruit to develop to its maximum size.”

Winter grafts on deciduous fruit trees

Between January 29 and February 25, I took scion wood and grafted onto my deciduous fruit trees. I used the whip method for all nine grafts, and seven of the nine are growing today.

Red Baron peach grafted onto Snow Queen nectarine. Both buds growing out. Painted a blue swatch behind the graft so I'll always know which branch is the Red Baron peach.

Red Baron peach grafted onto Snow Queen nectarine. Both buds growing out. Painted a blue swatch behind the graft so I’ll always know which branch is the Red Baron peach.

Over the last year, I’d┬áplanted four new deciduous fruit trees, but I wanted more varieties and I wanted an extended harvest period. So I decided to graft at least one extra variety onto each tree. I now have two varieties of apricot on one tree; a nectarine tree with two additional peach varieties on it; a pluot tree with an additional pluot and a plum; and an apple tree with two varieties.

For most of the grafts, I completed the work on the very same day that I cut scion wood, but for two of them I kept the scion wood in the fridge for a period of time before grafting. One of these refrigerated grafts didn’t take, but the other did. Therefore, I can’t say it made much difference how “fresh” the scion wood was.

I matched the size of the scion wood to the size of the stock and made diagonal cuts that matched in length. Then I wrapped them together with green nursery tape — a simple “whip” graft. Before the grafting, I had cut the scion wood to two buds beyond the diagonal cut and wrapped them in parafilm. (For one of the peach grafts I cut to only one bud and it took just fine. In the future, I may always use only one bud.)

No grafting expert am I. Last year, I followed the same procedure on another peach tree and it worked so I repeated. That’s the extent of my experience and skill level regarding deciduous fruit tree grafting. The magic seems to be only in the timing and the matching of scion to stock so that the cambium layers connect.

Why did two of the nine grafts fail? I’d guess I just didn’t get a tight and direct contact between the cambium layers of the scion and stock. That half of the magic wasn’t there.

An apricot graft that hasn't grown.

An apricot graft that hasn’t “taken.”

But my success rate of seven out of nine surprises me, and it tells me that the grafting process is something that anyone can do well.

Here is a detailed slide presentation on grafting by Chuck Ingels of the University of California Cooperative Extension. Incidentally, this presentation also talks about “budding,” which I had success with on a peach last year as well. Budding is an even easier technique than grafting in many ways, and so I’ll likely try more of it this summer.

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