Homeowners with citrus trees often question the proper time to initiate harvest of the fruit. The answer is complicated and based on several factors. Obviously “no fruit is ready before its time.” But what time is that?

Citrus, with the exception of lemon, ripens no further after picking. All citrus will store well in refrigeration, but quality will not improve past the level at harvest.

Variety of citrus is probably the highest priority to consider. Satsumas tend to ripen before navel oranges, which ripen before grapefruit. Usually ripening happens at a specific time of year, but may vary by as much as several weeks depending on condition of tree, drought, early temperature variances or weather conditions. Be aware of past history as a beginning point, but be prepared to be flexible. Select one fruit on a weekly interval to better judge results.

Color: Deep-green-colored fruit are sour. As fruit nears ripening, skin color lightens to a pale green color and breaks into yellowing. In South Louisiana, skin color can be dark green, change to yellow and convert back to greenish if a long warm period follows the early color change. Fruit color from out to in; top to bottom and sunny to shady. No tree has fruit ripened equally, so proper selection is necessary for success.

Taste preference: Some growers like the first tangy bite of satsumas. Others wait till deep yellow skin indicates a syrupy sweetness. Satsumas are found locally in five major varieties. The old standards "Owari" and "Brown Select" produce quality fruit that ripens in early November and lasts till after December. However, varieties with early-maturing fruit starting in early September have skin that stays greenish but yields fruit that is sweet. These varieties, such as "Armstrong," "Louisiana Early" and "Early St. Ann," will peak in flavor but quickly become diluted in taste quality within weeks. In this instance, once fruit reaches desirable taste, regardless of color; harvest and put it in refrigeration. Otherwise, harvest and share with neighbors, because quality will decrease.

The storage of fruit on a tree maintains a tree’s vigor in a period when the tree would be better served by being allowed to halt its growth through a pre-conditioning or slowdown. Trees should be completely stripped of fruit prior to January of each year. This allows trees to prepare for the traditionally coldest periods, and trees will maintain a sufficient energy level for next year’s blossom production. Keeping fruit late on trees has proven to lessen next year’s crop.

Problem areas: Usually fruit that has stayed and developed on trees until now will continue and mature. Two exceptions to this are fruit splitting from excess water absorption or insect attack. If fruit has split vertically, then it indicates the fruit absorbed water quicker than the skin could, so a split occurs. This is often seen in satsuma and navel orange trees. Secondly, if plant bugs attack satsumas and stick their beaks into a fruit section, the fruit often turns yellow and drops. If one tree has many dropped fruit or several are bright yellow while most are green, then look for the large brown leaf-footed bug as the culprit. Spray malathion as directed or call your county agent’s office for more specific directions.

Remember, citrus ripens differently by variety, location on tree, tree health and weather conditions. But follow a few rules and enjoy the best tasting fruit found anywhere.

Here is a schedule of *normal citrus harvest periods:

Satsumas

•Early St. Ann – late August to mid September

•Louisiana Early – late August to mid September

•Armstrong – mid September to early October

•Brown Select – mid October to mid December

•Owari – early November to mid January

Oranges

•Navel Orange – mid November to late December

•Blood Orange – early December to early January

•Louisiana or Hamlin Sweet Orange – mid November to January

•Other seeded Oranges – mid November to January

•Valencia – mid March to April

Other

•Grapefruit – mid December to January

•Kumquats – late November to January

•Pumelo – early November to late December

•Mandarins – mid October to mid November

*Normal indicates average dates categorized over a number of years. Begin sampling or scout looks of fruit two weeks prior to indicated date. This will take into account weather, stress or other factors that alter normal maturity dates.

Source - http://blog.nola.com/