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Why Are My Oranges Sour?

Why Are My Oranges Sour?

From time to time we get questions from clients who are unsatisfied with the flavor of the fruit from their citrus trees.  Usually the complaints are because of dry or fibrous fruit.  This is usually due to irregular irrigation and/or excessive rains during fruit development.  However, we sometimes get asked about fruit that is too sour.  There are three common reasons why fruit may taste more sour than expected: 1) The fruit came from the rootstock portion of the tree; 2) The fruit wasn’t fully mature when picked; or 3) the tree is infected with Huanglongbing (HLB) a.k.a. citrus greening or yellow dragon disease.

Rootstock

The majority of citrus trees are grafted onto a rootstock.  Grafting is the practice of conjoining a plant with desirable fruiting characteristics onto a plant with specific disease resistance, stress tolerance (such as cold tolerance), and/or growth characteristics (such as rooting depth characteristics or dwarfing characteristics).  Citrus trees are usually true to seed, but the majority of trees available at nurseries and garden centers are grafted onto a completely different citrus species.  Some of the commonly available rootstocks produce sweet fruit, but most produce sour or poor tasting fruit.  Common citrus rootstocks include: Swingle orange; sour orange; and trifoliate orange.  For a comprehensive list of citrus rootstocks, please visit the Florida Citrus Rootstock Selection Guide.  A rootstock will still produce viable shoots, which can become dominant leaders on a tree.  In the picture below, a sour orange rootstock is producing a portion of the fruit on the left hand side of this tangerine tree.  The trunk coming from the sour orange rootstock has many more spines than the tangerine producing trunks.

A tangerine tree on a sour orange rootstock that is producing fruit on the left hand side of the tree.

A tangerine tree on a sour orange rootstock that is producing fruit on the left hand side of the tree. Photo Credit: Matt Lollar, University of Florida/IFAS Extension

Fruit Maturity

Florida grown citrus generally matures from the months of October through May depending on species and variety.  Satsumas mature in October and taste best after nighttime temperatures drop into the 50s.  Most tangerines are mature in late November and December.  Oranges and grapefruit are mature December through April depending on variety.  The interesting thing about citrus fruit is that they can be stored on the tree after becoming ripe.  So when in doubt, harvest only a few fruit at a time to determine the maturity window for your particular tree.  A table with Florida citrus ripeness dates can be found at this Florida Citrus Harvest Calendar.

Citrus Greening

Citrus Greening (HLB) is a plant disease caused by the bacterium Candidatus Liberibacter asiaticus, which is vectored by the Asian citrus psyllid.  The disease causes the fruit to be misshapen and discolored.  The fruit from infected trees does not ripen properly and rarely sweetens up.  A list of publications about citrus greening can be found at the link Citrus Greening (Huanglongbing, HLB).

A graphic of various citrus greening symptoms.

A graphic of various citrus greening symptoms. Photo Credit: University of Florida/IFAS Extension

Satsuma Harvest Season in North Florida

Satsuma Harvest Season in North Florida

Nice crop of satsuma fruit

Nice fall crop of satsuma fruit. Photo credit: Larry Williams

When asked what kind of citrus to grow here in North Florida, my default response is satsuma. I usually get a funny look, followed by an attempt by the person who’s asking to repeat the name satsuma. The individual may ask, “What is satsuma… is that a citrus?” I guess the person expected to hear orange, grapefruit, lemon or maybe tangerine.

Satsuma is a type of citrus, technically classified as a mandarin and is sometimes referred to as satsuma mandarin.  The satsuma mandarin is a good candidate for the North Florida citrus enthusiast for a number of reasons.

  • Historically, mature dormant trees have survived minimum temperatures of 14°F to 18°F when budded/grafted to a cold-hardy rootstock such as trifoliate orange or swingle, a trifoliate orange cross. Young trees are not as cold-hardy but, due to their smaller size, are more easily covered with a cloth such as a sheet or lightweight blanket for protection during freezes.
  • Satsuma fruit are ready to harvest October through December, ripening before the coldest winter temperatures. This is not true with most sweet citrus types such as oranges, which are harvested during winter months. Harvesting during winter works well in Central and South Florida where winters are mild but does not work well here in extreme North Florida. The potentially colder winter temperatures of North Florida are likely to result in the fruit on sweet oranges freezing on the tree before they are ripe, potentially ruining the fruit.
  • Our cooler fall temperatures result in higher sugar content and sweeter fruit.
  • Fruit are easily peeled by hand, have few to no seed and are sweet and juicy.
  • Trees are self-fruitful, which means that only one tree is needed for fruit production. This is important where space is limited in a home landscape.
  • Trees are relatively small at maturity, reaching a mature height of 15 to 20 feet with an equal spread.
  • Branches are nearly thornless. This may not be true with shoots originating at or below the graft union. Shoots coming from the rootstock may have long stiff thorns. These shoots should be removed (pruned out) as they originate.

Satsuma fruit are harvested in fall but trees are best planted during springtime when temperatures are mild and as soil is warming. Availability of trees is normally better in spring, as well. For additional cold protection, purchase a satsuma grafted on trifoliate orange rootstock and plant the tree on the south or west side of a building. There are a number of cultivars from which to choose.

For more info on selecting and growing satsuma mandarin, contact the UF/IFAS Extension Office in your County or visit the following website.

https://edis.ifas.ufl.edu/ch116

Video: Stevia, As Sweet as Can Be

Video: Stevia, As Sweet as Can Be

Stevia grows well when planted in the ground or in a container. Learn basic care in the garden and how to use fresh leaves to sweeten your next dish or drink with UF IFAS Extension Escambia County’s Garden to Table segment.

‘Patio Baby’: An Eggplant for Any Space

‘Patio Baby’: An Eggplant for Any Space

In my ongoing search for low-maintenance vegetable varieties that perform well in small spaces, like my raised bed garden, I decided to try a newish Eggplant variety called ‘Patio Baby’ this summer.  Developed by PanAmerican Seed and winner of the 2014 All-American Selections Vegetable- edible category, I was drawn to ‘Patio Baby’ due to the advertising claims made that it was a true miniature variety, perfect for growing in containers, only reaching 20” or so in height and producing both “early” and abundant fruit.  I’ve been very pleased with the performance of this extremely unique variety so far in my informal backyard trial and definitely think it deserves consideration in your garden too!

‘Patio Baby’ fruit ready for harvest in September 2020. Photo courtesy of Daniel Leonard.

The first observation when seeing a mature ‘Patio Baby’ is how small the plant is, leaves, flowers, fruit, everything.  Compared to a standard ‘Black Beauty’ variety, ‘Patio Baby’ plants measure maybe a third as tall and wide.  Where a “normal” eggplant fruit might be slightly larger than a softball and often have spines on their calyxes (the green part that connects the purple fruit to the stems), ‘Patio Baby’ fruit are roughly the size of a large chicken egg and totally spineless!  I find this smaller plant and fruit size to have several perks.  Vegetable plants that grow 2’ tall and wide are just about perfect for raised bed gardening.  If you don’t require a large quantity of eggplant, you won’t have to sacrifice an entire bed’s space to ‘Patio Baby’ like you would with the standard varieties. Also, ‘Patio Baby’ fruit won’t bend or break branches and are held strongly on the plants, with no need for staking, another bonus when space is at a premium.  Finally, I find it much easier to harvest, handle and prepare the small, spineless ‘Patio Baby’ fruit in the kitchen.  Think of them as a “personal pan” eggplant.  As I’m the only one in my house who eats much eggplant, I waste a lot less fruit cooking these little guys!

‘Patio Baby’ mature fruit. Standard house key used as a size reference. Photo courtesy of Daniel Leonard.

‘Patio Baby’ Eggplant also lives up to its reputation of being exceedingly easy and quick to grow.  I purchased a packet of ‘Patio Baby’ seed from Johnny’s Selected Seeds in June and planted three in a 20” diameter decorative pot next to my raised bed garden during the first week of July, behind summer squash that had recently expired in the heat of late June.  After sprouting, the plants grew strongly and, true to form for most Eggplant varieties, were bothered by no serious pest or disease issues other than the normal stinkbugs and occasional caterpillar that plague summer gardens in Florida.  Around 8 weeks from sowing seed in the soil, cute, egg-shaped fruit were ready for harvest!  Over the next three or four weeks, my single plant produced around 50 of the cute little fruit.  More than enough for me and plenty to share, the goal of my gardening endeavors.

‘Patio Baby’ produces lots of fruit in a small package! Photo courtesy of Daniel Leoanrd.

If you’ve run out of space in your raised bed garden, just want a single plant for your back porch or simply want to try a novelty vegetable variety, my experience this summer deems ‘Patio Baby’ Eggplant is an excellent option!  For an eggplant that is space-efficient, very early and heavy producing, and comes in a more easily harvestable, kitchen-friendly package, try ‘Patio Baby’.  For more information about raised bed gardening, vegetable varieties or any other horticultural topic, contact your local UF/IFAS County Extension Office.  Happy Gardening!