Coming into the produce business with plenty of food knowledge but no agriculture background to speak of, I’ve learned a bit on the job. There’s not much agriculture knowledge required for what I do, but it’s nice not to be completely ignorant when you spend at least some time talking to farmers, so I’ve been on a few field tours and I try to ask good questions on occasion. I love to observe, and I learn a lot from just noticing practices and then asking an expert if what I think I’m seeing is correct. Here’s a recent one like that.
These trees are tied down. It’s not to keep them from blowing or washing away (although with the sixth-wettest March since record-keeping began in 1878 – 4.73 in., with normal being 2.2 in. – this would be the point at which you’d start to worry about things washing away, even in the basketball-court-flat San Joaquin Valley).
This is an orchard of plum trees that are tied to stakes in the ground for training. Plum trees have a strongly upright growing habit. (Peaches and nectarines have a spreading habit.) Training plums this way helps them grow a little more spread out, in what’s called an “open vase” or an “open center” style.
These trees, planted last year and now on their “second leaf,” have four or five branches (technically called “primary scaffolds”) that will eventually support the weight of the tree’s fruit. These long branches will probably be cut back this year to between two and three feet, and two secondary scaffolds will be allowed to grow from each primary scaffold.
As with just about every agricultural practice, there are other ways to accomplish this. One other I’ve seen, and haven’t had a chance to take a picture of yet, is the use of lengths of wood – sometimes prunings taken straight from the same orchard – in the center of the small tree to prop the future scaffolds apart. This takes less time than staking, but is also less secure.
Either method achieves the same result: it makes the trees easier to manage as they grow and need to be thinned, harvested and pruned. However, training is not simply for the sake of convenience. Having a tree with an open center allows more sunlight to reach the fruit, which helps the plums gain color better as they mature. Additionally, an open tree enjoys better air circulation, reducing the risk of fungal diseases taking hold.
Though if left to their own devices they might produce a small crop of plums, these trees will likely not be harvested this year. The fruit will probably be knocked off the tree – in order to allow it to put more energy toward growing the structural framework that will make it a strong bearer in its third leaf.