Just harvested my latest navel oranges. Nice and juicy. The only problem is that they are not very sweet at all. Am I missing something in the soil? Thanks

Some of the reasons could be:
Tree is still too young.
You harvested earlier than their peak time for quality.
You harvested later than their peak time for quality.
It was not warm or hot enough during the fruit filling phase to produce more sugars.
You did not supply enough K.

Hi<my two cents worth.I read somewhere,that it is the cool/cold temps that
make the fruit sweet,not the heat.That is why citrus doesnt grow well in the tropics because they need the cool temps to convert the acids to sweet.You
probably picked to soon.I know my lemon is better when it goes a dark and
shiny yellow.Try again with your next fruit! good luck

So how come us here in the colder northern California never match the sweetness of Navels and Valencias grown in Southern California? So what you read could be dead wrong in the context of California regional differences, but it could be true in another context and with another cultivar. I have observed this last harvest with my blood oranges but not my navels and valencias. Cara-cara for example still remained lousy tasting even though we had cold arctic blast, but this coincidentally have tasted the best from my moro and tarocco so far.

It is a well known fact that Florida oranges are a lot sweeter, with low acid content than California's simply because they have a higher night time temperature and also higher average daily temperature near and around harvest time and the diurnal fluctuations in temperature are not as dramatic as that of California. California oranges are sour even if it is very cold when they ripen which is usually from late fall to winter. It is the alternating extreme temperature in California that develops the oranges deep dark color but higher acid. In fact most fruits aside from citruses also develop interesting blend of higher acid and higher sugars because of these extreme diurnal fluctuations during the fruit filling phase. Master Gardeners here have observed that generally it is the heat that makes the grapefruits and oranges better or sweeter. The coastal areas where it is also cooler and have lower variations between night and day temperatures have poorer tasting pummelos, grapefruits, valencias, and navels compared to those in the inland. The mandarins in the coastal areas are generally okay, as well as those grown in Northern California.

So there could be other interacting factors. In the Philippines, people believed that planting citruses higher up in the mountains where it is cooler claimed that the oranges are sweeter. I think the main reason is that the area is relatively new and disease free, so you get high quality citrus fruits. In the lowlands where pests and diseases are prevalent, it makes the citruses bitter and poorer in quality even if it should have been much sweeter. We call those interactions with other factors.

I believe that there are specific ranges of temperature that brings out the best in the taste of citruses specific to the regions. If in excess at both extremes it could be bad to some cultivars. The specific pattern of diurnal fluctuations may also result to differences in the quality of various cultivars. What might be good for one may be bad for another.

I've read where the amount of sun is what affects the sweetness of an orange. Last years oranges were sweeter than this recent bunch. Last years also had a more orange flesh color. This years the color was an orangish pink. Was very odd. I admit I was a bit confused as to when to pick them this time around. They all had green tops to the rind. However, one actually fell from the tree itself. I noticed some mold starting on the others around the navel area. I thought it best to pick them all rather than let that continue. As I mentioned, the flesh was very juicy...except for some of the area around the top where it was green. That area was a bit harder and drier. So maybe I did pick them too early but was unaware of some kind of fungus issue going on with the fruit??

The fruit themselves are far from being attractive. Is there some sort of sprays I need to consider while the fruit is developing? Thanks guys.

Ohiojay, here in California, it is not the amount of sun that will affect the sweetness of our oranges. I have oranges that are completely shaded half of the day and their sweetness is the same as those exposed to sun the whole day. But there is a very big difference, the one that is shaded have significantly fewer fruits than those in the full sun. I have friends who have oranges bordered by concrete wall in the north side which gathers the radiation during day and gives off heat during the evening hours so that technically they have way higher average microclimate temperature than I do, and their oranges are super sweet.

the cleanliness of the oranges is generally affected by humidity. But the mold that you are referring to are sooty mold. You can easily clean those oranges by brushing them off using a big nylon brush. To keep your oranges "soot" free, you will have to control the ants climbing up the citrus tree. These ants herd up various scale insects and aphids which in turn give out sugary excreta which in turn feeds the ants and the sooty molds. the target control are the ants and not the aphids and scale insects. It is easier to control the aphids and scale insects but the ants will simply "replant" them as soon as it is safe for their re-entry and surely by the time you already neglected to inspect the tree. There are various ways to control the ant from climbing up the citrus tree.

I've tried successfully using saran-wrap at the base of the tree, making sure the other end of the saran wrap is buried under the soil at the base of the trunk, then a dab of sticky stuff like vaseline on the saran wrap or other grease that are harmless to the plants. Most people will use the Tanglefoot product which to me is overly expensive and you can concoct your own. Make sure there are no other parts of the citrus that the ants can climb through. After solving the ant problem, then you will have to deal with aphids and scales only one time. Do it next season way earlier and you will have a clean tree with clean fruits, but this time control the other insects with lady bugs which you can order online or buy from the stores. Our local home depot stores have them, and they are very cheap too.

Shouldn't I "see" ants now and then though? I have scale on one plant and the aphids are driving me to drink a little more than usual. I've never seen a single ant in my greenhouse! So it's really hard for me to believe they are the culprit here. Isn't it odd to not see any? But I'm not one to ask for advice and then not take it. I'll try your suggestion on a couple of the plants and see what happens. I can rid the aphids from a particular plant and then a few days or so later I see the little $%#@&*(^ again.

Do you also believe I picked them too early? Thanks Joe.

Ohiojay, if you don't have that much ants, then deploy the ladies in red (lady bugs). Trichogramma wasps will also parasitized on aphids. Without ants to protect the aphids and scales, the control using lady bugs are effective and would last a long time.

The problem why biolgical control are not effective because the ants fight off anything that will attack their "sheep". Without those ants, then you can use natural predators.

I have a solution to your ant problem,that works for me anyway.Put saucers
under your containers but elevate them with bottle tops or 3 chunks of wood,so they wont sit in water.put vaseline around the lip of the saucers,
then make sure there is always some water in the saucers.That means the
ants would have to climb over the vaseline then swim to your pot and climb
up! it adds a little humidity too.Maybe,just a cm of water in saucer,it mustnt
be in contact with the bottom of pot.Citrus dont like to sit in water. Top up that water every day and keep an eye on the vaseline and thats a cheap
way to keep them away.good luck

The discussion on sweetness in citrus makes me wonder if there are different time scales at work-- maybe heat and cold affect different parts of the fruit maturation period differently. I do associate the sweetest naval oranges and mandarins from So. LA with the year when there was a cold spell a couple weeks before we went-- I have been buying directly from fruit stands over there in Jan for about 5 years. This past season, early Jan was warm and wet and fruit was not as sweet and had less flavor to me--although their naval oranges are much better than what I have gotten in the store and peels are much thinner.

All i know,is we import oranges from the u.s.a here in new zealand and they
are by far the best we get.We grow our own here and we also import from
australia but neither are as good as yours.If the heat was the main factor in
sweetness,then australia should produce oranges etc just as good as yours.
The reason they dont,is because citrus need a cool period to initiate ripening.
I have grown all sorts of fruits and veg.From experience,big usually means
more tasty.The heat stimulates growth and size,along with nutrients and
moisture but if you pick too early they will not be ripe.If heat was the sweetening factor,it would mean we could pick citrus before they are ripe and they should taste sweet then! Nitrogen is the main nutrient to help size up
your citrus and help them reach their full potential.My guess is that you have
very good extremes of temps.Hot in summer for maximum growth and cool
then cold for ripening of fruits.The aussie oranges we import are big but
they dont go a lovely orange like yours because they dont get lower temps.
I must try to find out where the oranges we import from the us are grown.I
think they are from california. Aussie is too hot and never cold,hence their
fruits dont fully ripen.Just like if you were to grow in the tropics.Any fruit is
best at its peak ripeness.Keep growing those yummy oranges anyway!!!our temps have just dropped here,heading from autumn to winter and all my mandarins have started going orange in response.We dont get that hot summers here,so our fruits dont tend to get that big.
Of course,things are different for you guys in your neck of the woods.Its
all good fun,whatever.maybe millet might shed some light on this? cheers

You guys in Northern California cannot match
us here for sweetness for several of the Navel
forms of Oranges. We get both the heat during
the Summer which later allows for flavor and the
cold at the right time in the Winter to color up
and sugar up our fruit. The better Navel fruit,
mostly Washington Navels and a few of the old
Shamouti and a Washington Navel (seed parent)
crosses that are still around come off the trees
before Christmas here.

If you had attended the Lindcove Citrus tasting
this year you would have tasted some Navels and
some of the earlier ripening Mandarins that are
far more flavorful and sweeter than any of those
that you will get from a grocery store. The Dobashi
Beni Satsuma was "killer" for flavor but had not quite
sweetened up yet to its best but most people would
not know that it needed another two weeks to be
fully mature. With the flavor it had it did not need
to be any more sweet than it was. The Fukumoto,
the Rocky Hill and the Washington Navels as a group
were at their peak for flavor and sugar content was
good to real good then by mid month of December.
You guys have this all wrong, it is not sweetness
that matters most it is flavor and I am beginning to
wonder who all in this forum knows what these
plants are supposed to have for flavor. Once we
have the right flavor then sweetness and juiciness
will matter. Besides what good is sweetness if
the fruit is insipid? There were a few of them at
the tasting. I am not going to go out and grow
them. Some of you with your comments make
me feel like a dinosaur in today's world. There
is a reason why I do not post much in this forum!
I've been "put out to pasture" here.

Joe, don't get sucked up into the thinking from
the South, there are some people still around in
the Sacramento area that know what I am telling
you. I used to work under and worked alongside
a few of them from your school up there in Aggie
land. [Our high school team won your Entomology
FFA Field Day contest twice in a row. I was an
Agronomy judge my first two years in competition.]
Most of us were involved in studies with other
plants (me, in plant disease control of Fruit & Nut
trees mainly but with Citrus and Grapes as well)
but we all had our own way of finding ourselves
trickling down to Lindcove, long before the UCR
people were seen around there much.

Jim

Thanks Jim (Snickles)! Although I am heavily involved with crops and computers, aka systems, phenological, expert systems, agroecological systems, microclimate, agrometeorology, anything that involves very heavy math and stat applied to agriculture, for sure I'll be there, still, it was my passion to raise fruits beyond those from simulations and modeling, especially those plants that I have not worked with.

Yes I agree with you all that there are some time scales at work, as to when those temperatures sets in versus phenostages of crops and fruits. That is why we have various mileages, and they easily manifests themselves in the fruit quality of citruses. California is the State with most number of zones so we have tremendous variations. Majority of citruses are good tasting in the South, but we have a few surprises here in the North, in fact only very few surprises.

One of the best citruses that I ever tasted was from a home ranch of a UCR alumni (couple), already retired, and their home was atop a hill somewhere in Murieta down there. Every afternoon, the localized orographic uplift brings warm dry winds through their citrus groves that extends well into the evening hours like 9 to 10 pm, and they produced the best tasting Washington Navels that tasted like Honey, and the Cocktail Grapefruit hybrid is the best. Of course I regrafted their lemons with whatever they want to have more, like the cocktail grapefruit.

Over here in Davis, all of our Washington Navels and their sports like the Cara Cara are not sweet and yet they are insipid at the same time, a double disappointment. So I am trying out various ripening stages with many different cultivars. Gene Lester has been avoiding planting Navels and Valencias for similar reasons. On the other hand, I keep pressing on until I find the right valencia and navel cultivars until I find the ones which will produce the best taste quality that match well with our climate. Of course will share this with you all when the time comes. As long as the big box stores are only selling the regular valencias and regular navels, we will never know, so am grateful to the UCR CCPP budwood program as I can try them all even with limited space.

So for evaluation, i would always try out the Gene Lester Citrus tour instead of the Lindcove nursery. So far majority of mandarins (Satsumas, tangerines, clementines) and some Pigmented Oranges (Tarocco, Moro, Vainiglia Sanguigno), are very satisfactory and taste better than those I get from CostCo or Safeway. The Oro Blancos, Chironjas, Wekiwa, Tangelos and other grapefruit hybrids are not disappointing either, and surely that we are in the inland, our crops tasted better than the coastal folks.

Of course Calamondins, kumquats, lemons, sudachi and Yuzu, don't care much how cold or hot you are, they taste relatively the same to me.

I am just some shmuck trying to grow citrus way outside the citrus belt. I have enjoyed this discussion. What I have done with my citrus is cover them in a portable greenhouse to give them a spring kickstart. We dont get enough natural warmth to get the new growth (and buds) going until later in the spring. Which of course delays the fruit ripening at the back end. last year, my Changshas did very well in a pot ( not in a greenhouse). The golf ball size fruit turned green to orange as the night time temperatures diped into 40s in late September/ October. I brought them into a unheated garage before the first frost and the fruit stayed on the tree until we ate them at Christmas. They were very sweet.

I am experimenting with many different (20) types of citrus. As with any experiment I have to accept that there will be failures along the way.
What I am doing is trying to find which cultvars will produce the most enjoyment in my environment. THEN promote those locally. The Meyer lemon is the first past the post. Good fruit, low heat requirements, fast growth.In second place is the Changsha Mandarin, sweet fruit, growth TBA.

I have read tht the Trovita Navel has low heat requirements to ripen off the fruit. Is this correct? How does the taste compare to the Washington or other navels? BTW I cannont find a trovita anywhere in the Vancouver area...

Greg