LSU AgCenter Horticulturist
(08/21/20) Fig season is well underway, and many fig varieties are wrapping up their production while others are still producing and ripening. Fig season can begin in Louisiana as early as mid-June and end as late as early October, depending on the varieties. Your trees may still have green figs that just won’t seem to ripen, and that can be for many reasons.
First off, fig trees have a long juvenile period where they will not make fruit. Depending on the variety, they may take anywhere from two to six years to begin producing fruit. Those mature enough to produce fruit can take up to two months from fruit formation to optimal ripeness. In this instance, you just need to be patient.
Beyond the age of plants, the next possible cause for figs to not ripen could have to do with environmental factors such as temperature, water, nutrient levels and amount of light in addition to biotic pressures such as weeds, pests and disease.
Stress is the main reason why fig fruit will not ripen. Fig trees are extremely susceptible to stress, which causes them to slow down or even stop ripening their fruit. The most common stress is lack of water in high-heat conditions. Fig trees have a shallow root system, and irrigation is extremely important. If a fig tree does not receive an adequate water supply, fruit may not form or will not ripen.
Annual rainfall in Louisiana is typically very high — 60 or more inches of rain annually. However, rainfall data from 2020 for the months of May through July are showing an average of 2.45 inches less than 2019 rainfall for those three months. August data will likely show a further decrease in some parishes.
Stressed trees will go into survival mode, conserving their energy in an effort to help them stay alive and reproduce by conserving their seeds. Trees conserve energy by diverting it from the ripening process. Fruit will not ripen or will drop prematurely in addition to dropping leaves in their effort to stay alive.
One hard fact about figs is, unfortunately, green figs will not ripen off the tree. However, fruit picked just before full ripeness will continue to soften and become sweeter when they are stored at room temperature in a dry location, such as a pantry.
Ripeness is most often determined by enlarged size and a color change from green to brown or purple and sometimes gold, depending on the variety. You can feel for ripeness by gently squeezing the fruit, and it feels soft to the touch. Unripe figs are hard and have a rubbery feel to them. Additionally, ripeness can be determined by sweetness: the riper the fig, the sweeter it is.
Other possible reasons fruit will not ripen are a lack of nutrients, insufficient sunlight, too much nitrogen, pests or disease. In an effort to protect itself from pests or diseases, a tree will divert energy from fruit production and ripening into fighting off pests and disease. Scout often for pests and disease, and treat affected trees as soon as you spot them.
Fig leaf rust is a common disease that affects the trees. It is a fungal disease that affects mostly the leaves, and it thrives on humidity and moisture that is prevalent here in Louisiana. Trees respond by dropping their leaves in late summer or early fall. Fruit is not typically affected, but the disease can cause premature ripening of the fruit.
When planting fig trees, provide adequate spacing to improve air circulation in addition to using good pruning practices to open up the canopy. Avoid overhead watering, but water at the base of the trunk. Remove fallen, diseased leaves and discard them in the waste to prevent further disease spread.
No fungicide is registered for use during fruit production. Rust can be treated when trees are bare during the winter or dormant season followed by repeated treatments every two to three weeks to help prevent rust from reoccurring on the next year’s foliage. Never spray when fruit is present.
Making fruit can take a great deal of energy and work by the tree. A tree requires extra nutrients to support both itself and fruit. If the tree lacks proper fertilization, the figs slow the ripening process or may even stop. Additionally, over-application of nitrogen can also reduce ripening.
Regular fertilizing will help promote fruit production and ripening. Do not fertilize in late summer because succulent growth is more susceptible to cold injury in the winter. Wait until late winter or early spring and apply 1 pound of 8-8-8 fertilizer per year of age of the tree up to 10 years old.
Prune back one-third to one-half of the plant in early spring after the danger of the last frost has passed, typically March 15 for south Louisiana and after April 1 in north Louisiana.
To help improve fruit production and ripening of fruit, make sure the tree has plenty of water, especially during extremely hot temperatures, proper nutrients and proper maintenance. And scout for pests and disease regularly.
Fig fruit ripens on the tree. Photo by Heather Kirk-Ballard/LSU AgCenter
Ripe figs are sweet and juicy. Photo by Heather Kirk-Ballard/LSU AgCenter
Fig leaf rust on a fig leaf. Photo by Randy LaBauve/LSU AgCenter