Things to do before spring flowering

Were you disappointed by your fruit set last year? Lots of flowers on the trees, but little fruit to harvest at the end of the season? Maybe you have a boron deficiency.

I'm pretty sure I do. I live in a wet area where rains would leach available boron out of the soil. And while my apple trees flower, the fruit set is nothing to crow about. So this week I did a foliar application, oops, make that a bare limb application, because we are still a few weeks away from the trees leafing out. You can get boric acid at any dollar store, it is sold as roach and ant poison (if you read the label and it says orthoboric acid, don't worry, it's the same thing). Just one little squirt of the powder, about a gram or so, into your compost tea bucket or the hose-attached garden sprayer, and you will be putting enough boron where it needs to be.

Boron doesn't translocate very well in plants, so foliar application is a proper method to use, because it will be absorbed into the bark on the branches and the swelling flower buds. It also has a narrow window in between deficiency and toxicity, so you want to make frequent weak applications. Adding just a gram or so to a 5 gallon bucket of compost tea is just about right, as that is going to make it in the range of 10-20 ppm of elemental boron. Doing this now and the day the tree first flowers and a third time when it is just past peak flower is probably a good plan.

And for those of you in the arid west, where soil boron is at very high levels, all I can say is "never mind".

It's that time of year, folks. Two of my plum trees are in full flower now, and the pears are just starting. I've been reading this article Movement of Boron Out of Tree Fruit Leaves, which leads me to believe I've been too timid with my foliar applications. I was putting about 1 gram of boric acid in a 5 gallon bucket to make my foliar application solution, and it looks like he is using around 3 grams of boric acid per liter.

Last year was a bust here due to a late freeze, no persimmons or pomegranates, and the apples, pears, and plums were very few. The weather forecast this year looks much better, so I'm going to get out and get serious about the foliar feedings.