Available space is key
After you have selected your market and your varieties, next comes what most scientists say is the most important decision: analyzing your acreage and deciding your tree density.
"For the future, we are not going to be able to plant our citrus groves the way we have in the past. We are going to, and growers are already moving in this direction, design the grove so that it will produce high yields in earlier years in order to get a cash flow coming in sooner than later. We can't plant a tree any more and expect it to break even in six or seven years and become the most productive on a per-acre basis at nine or 10 years. We need that within four or five years," Rouse says.
The standard for current plantings is using a north-south orientation, 24 to 25 feet between rows and 10 to 15 feet within the rows. While the orientation isn't changing, the distances are being tested and altered by many growers and scientists trying to achieve maximum light interception.
Futch says to think of a leaf as a solar collector. The more leaves a grower has collecting the sun, the better off he is going to be because there will be less bear ground collecting the sun, thus producing weeds, grass or other vegetation. If growers achieve the maximum light interception in a grove, they will have greater yields.
Growers are testing spacing between rows anywhere from 8 feet to 10 feet to 15 feet. While planting in such a manner is possible, part of the test is making sure trees remain manageable in these rows that are closer together. "You can be successful with smaller row spacing if you use a less vigorous rootstock, but you also can set yourself up for failure if you use the wrong rootstock," Futch says.
Rouse says planting trees closer together also helps when growers discover citrus greening in their groves. "When you tighten up your trees, if you do get infected, and you will, you could remove those diseased trees and other ones will fill in that empty space because they are already close together," he says. "You can afford to lose those trees and not lose bearing space or volume because the other trees will move in."
Another way to become more profitable is to use rootstocks that produce small- to medium-sized trees (also known as dwarfing trees).
"We can no longer, I believe, function with a 16 to 20 foot tree in height. There are a lot of labor issues and safety issues there to pick a tree," Rouse says. The industry standard, the swingle, makes a moderately sized tree already, and growers can maintain it around 12 feet tall. Other rootstocks on the market are topping out between 8 feet and 9 feet.