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Hastening Fall Fig Ripening
An ancient, but little known practice can provide a simple way to ripen figs 30 days or more before their normal ripening date. This practice, in use as early as the third century B.C., is known as "oleification" and consists of applying one of a variety of oils to the eye of the fig fruit at a time when it will respond by ripening at a greatly accelerated rate.
Oleification was probably discovered quite by accident, and one can only speculate about how it happened. However, since both figs and olives grow in the same region, olive oil and figs must have come together quite early. At some unknown time, someone found that the application of olive oil to the eye of green figs would cause them to ripen far earlier than untreated figs. Other oils have been shown to produce the same effect. Mineral oil has worked as well as vegetable oils.
There are a number of theories concerning the cause of the response, but very little evidence exists to support any of them. Several features of the "oil response" seem to support the theory that it is caused by a growth regulator produced by the fruit when influenced by the oil. Since many different oils, and even some materials other than oils, produce the same type of response, no component of the oil itself seems to be involved. Fig growers can continue to benefit from the practice while researchers puzzle about its method of action.
An added benefit is that several figs will ripen on each shoot at the same time, rather than at naturally occurring intervals of 1 or 2 days. The treatment to induce early ripening is quite simple, consisting of the application of a small amount of oil, usually olive oil or heavy mineral oil such as that used for medicinal purposes, to the eye of the fig. Care should be taken to avoid applying the oil to other parts of the fruit. The use of a small cotton applicator makes the job easy.
Timing the application is very important. Applying oil too early can cause the young figs to drop before ripening. Applications made too late are ineffective. Because of the bearing habit of the fig, however, this is not too much of a problem. Since the figs at successive nodes up the shoot are younger toward the tip, fruits of a receptive stage can usually be found.
In the varieties common to Texas, the receptive stage seems to coincide with the time that the pulp of the fruit turns pink. By cutting open a few fruits several days apart, beginning about the first of June, you can easily determine when the oldest figs on the shoot are receptive. An application of oil to the first three figs on shoots, made when the most basal fig shows pink pulp, will usually ripen three or four figs in a short period of time, often within 5 days after treatment. Untreated figs of the same age may require more than 30 days longer to ripen.
The Celeste (Sugar Fig) variety, which is a common variety in this area, often drops its fruit in the early part of the ripening season, usually following an early spring drought. When premature dropping occurs, the earliest figs on the shoots may already be affected to the extent that they will not respond to oleification. This merely means that figs farther up the shoot must be selected when they show pink pulp. In the absence of premature dropping, you can almost predict by calendar date the time of receptivity to the oil treatment, but using the color of the pulp as an indicator is much more reliable. Other varieties will respond in similar manner, although the acceleration of ripening is not as great late in the season.
When figs are ripened early, they are especially prone to bird damage, and some protection may be needed. Entire shoots can be enclosed in paper or net bags following treatment, and in some cases entire trees should be covered with bird netting.
Some investigators have reported that the quality of figs following oleification is lower than that of naturally ripened figs, with the measure of quality being the content of soluble solids, chiefly sugars. Other workers, however, have reported higher quality for figs so treated. Environmental conditions at the time of ripening will influence the sugar content of the fruit, whether they are naturally ripened, or accelerated in ripening by oleification.
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