Degreening of Florida Citrus
30 years ago a friendly competitor offered me the following friendly advice. He told me "never tell the customer that we degreen their fruit." He told me that his company tells their customers that "we ship your fruit the very same day that we pick it".
Since the degreening process (or "color add" where they actually paint the fruit) was required by law, and since the degreening process could take as long as 72 hours in November, I felt his advice was really dishonest. Right from the start, we have always explained the degreening process to our clients, and have never lost a single client by being honest and up front with them.
Incredibly there are still companies that tell their clients that "your fruit is shipped to you the same day it is harvested". This is despite the fact that their frut must be degreened just like everyone else's fruit. I have always wondered how their customers would feel if they realized that this was simply not the case
Progression of color in degreening process
What Exactly is Citrus Degreening?
Degreening is a process where green citrus fruit is placed into a "degreening room" where the atmosphere can be controlled as far as humidity and temperature are concerned. Then a carefully measured amount of ethylene gas is introduced causing the fruit to gradually change color. Typically the process lasts from 72 hours in November to as little as 12 hours toward the end of December.
Why would our fruit be picked green?
It is important to understand that the outside color of citrus fruit is not an accurate indication of whether the fruit has matured (ripened). Fruit that is green typically meets State established maturity standards for sugar, acid and juice content. Conversely it is not unusual for a crop to have good color and yet still fail maturity tests.
In Florida, early varieties of fruit such as Navels, Grapefruit and Tangelos typically do not meet color standards on the tree until mid December. The fruit however meets maturity standards as early as October. Both commercial and fund raising markets require the fruit be delivered prior to the end of December. As a result mature fruit is picked green and is then degreened to meet State and Federal color standards. Fruit that does not meet established color standards cannot be shipped.
Please remember that all Florida companies must abide by the same strict color standards, not just our own.
What causes fruit to turn color while still on the tree?
There are a number of factors that control color development of citrus fruit while on the tree. These conditions include:
- age of tree, and
- crop load
The most important condition is temperature. Cool weather (temperature that are less than 55 degrees) is needed to cause citrus fruit to turn color while on the tree. The more cool weather that the fruit is exposed to, the quicker it will turn color. Color changes can be readily observed in varieties such as grapefruit if the fruit is subjected to two or three cool nights.
Keep in mind that in Florida cool temperatures typically occur during the night, so the crop, typically, is exposed to these ideal conditions only for a few hours per day. When we bring the fruit in from the groves and place it in degreening rooms, we are able to control the conditions that the fruit is exposed to 24 hour per day.
The age of the tree is also a factor, with younger trees producing less color than older trees. Crop load refers to the amount of fruit that each tree produces. Typically, in years where the trees are abundant with fruit "heavy crop" color appears earlier than in years where the crop is "short".
Other factors that control color development on the tree include:
- types and manner of fertilization
- the amount of sunlight that the fruit is exposed to on the tree, and
- certain types of chemical sprays
These factor do not play as large a role as the climatic factors explained above.