San Antonio Express News
Sunday, November 27, 2005
By Dr. Jerry Parsons
Citrus trees are among the most popular home fruit trees in Texas. A couple of the most common questions regarding harvesting the fruit are, “When is citrus ready to pick?” and, “Should I pick all my citrus to keep them from being damaged by frost?” The new citrus webpage at: http://aggie-horticulture.tamu.edu/PATIOCITRUS/ in the “Harvesting” section gives the accumulated sugars of the new satsuma mandarin varieties in the fall of 2004. This data shows that most of the varieties had a soluble solids (sugar) reading of 10 by the middle of November but by the middle of December more of the varieties registered a 10 or more soluble solids. This data shows that the longer you can leave them on the tree, the sweeter they will get until they begin to drop in January. However, so you won’t have to eat a lot of fruit in a short period of time, you can go ahead and eat some of your Satsumas even if they are still somewhat green and tart in October and November. How soon the fruit reaches its maximum sweetness depends on fall weather conditions.
The fruit of the new satsuma varieties introduced by Texas A&M has reached its peak-harvest maturity. So that those who might want to grow satsuma citrus in their landscapes know exactly how these new varieties were evaluated during trials, (listed and described at:
http://aggie-horticulture.tamu.edu/PATIOCITRUS/varieties.html taste, next Saturday (December 3 ONLY!) samples will be available, and fruit will be sold of these named satsuma varieties from 11 a.m. until 3 p.m. The locations will be at Fanick’s Nursery on 1025 Holmgreen, Bragg’s Pecan House www.texaspecans.com in Hondo and at Milberger’s Nursery (3920 North Loop 1604 East – at the corner of Bulverde Road & Loop 1604). At the two nurseries, a taste testing will be conducted while Calvin Finch and I are doing the Milberger’s Garden Show from 12:00 p.m. to 2:00 p.m. on KLUP Radio (AM 930). At Bragg’s Pecans in Hondo and Milberger’s Nursery, you will be able to purchase recently harvested and shelled pecans for $8 per one pound bag. If this is successful, we may repeat it on Saturday, December 17, so folks can have Satsumas and pecans for Christmas.
Knowing when to harvest any citrus fruit involves the question of its degree of maturity. Technically speaking, there is no ripening process in citrus fruits and no such thing as “tree ripe” fruit. Citrus fruits pass from immature to mature and finally to an over mature condition while remaining on the tree, but the changes are slow and spread over several months. The only way for homeowners to determine maturity is to taste the fruit. Don’t expect citrus fruits to increase in sweetness or ripen more fully once you’ve picked them, as do peaches and some other fruits. When picked at any stage of maturity, the citrus fruit does not change after picking, except that it may decay or slowly dry out.
Unless damaged by freeze, citrus fruit keeps longer on the tree than if picked and stored so you’re not faced with an enormous harvest all at once. Also realize that a mere frost of 30 to 32 degrees F. will not injure the trees or fruit. Rather, it takes an extended number of hours below freezing to cause damage to both the tree and fruit. For example, it takes about four hours at 27 degrees F. to form ice in a grapefruit; probably a bit less in smaller fruit. Of course lush tender growth can be injured, but for the most part the trees should not really be in an active state of growth at this time of the year.
When you’re picking citrus fruit that you plan to store for awhile, be careful not to bruise or break the skin. Satsuma harvest should involve clipping ripe fruit off with pruning shears instead of pulling it to avoid skin damage. Fruits that are cut or scratched during harvesting will rot fairly quickly in storage. Citrus fruits with perfectly sound skin are fairly decay proof, and will last in cool, moist storage for several weeks (38 to 48 degrees F., 85 to 95 percent relative humidity).
Under dry conditions at room temperature, fruits develop off-flavors and shrivel within a week to 10 days.
Dr. Jerry Parsons is a Professor for Texas A&M University and a Texas Cooperative Extension Horticulturist for over 30 years in South Central Texas. For more information on this or other horticulture topics, go to www.plantanswers.com and our County Extension website at https://bexar-tx.tamu.edu.