A friend asked me how to know when to pick the tangerines from his tree. My first thought was, it’s obvious, you pick them when they taste good. But then I remembered that for some people gardening is full of rights and wrongs; he was afraid there was a correct or incorrect time to pick his tangerines.

There’s no such thing.

“Are the fruit mostly orange?” I asked.

“Yeah.”

“Then taste one.”

“I have.”

“Did it taste tart? Did it taste OK?”

“It tasted good, definitely not tart.”

“Then it’s time.”

 

Color: the weak indicator

We had been surfing during that terse exchange, but we don’t have to shout in between waves here. So let’s get nuanced, botanical, even maybe philosophical.

Part of the maturing process of oranges and tangerines in Southern California is that they eventually fade their rind color from green to orange. No sweet oranges or tangerines that I know of will be ripe in our climate before they’ve turned orange. So once they’ve changed color, you can consider giving them a pick and taste.

However, it’s true that some varieties turn orange long before they taste sweet. Take the Gold Nugget mandarin, for example. It’s a “late-season” mandarin. Here is a photo I took of my tree on January 15.

gold nugget mandarin tree

Orange fruit: they look ready. But they were still pretty sour on this date. Gold Nuggets from this tree don’t taste sweet until March at the earliest. So the rind color is something of an indicator of maturity, but its not directly linked to how sweet the inside is.

What causes the rind to turn orange, then, if not overall fruit maturity? Let me show you some “mandarinas” that I bought on a recent trip to Costa Rica.

(As an aside, let me acknowledge that I’m using “mandarin” and “tangerine” interchangeably in this article even though a citrus taxonomist might find this irritating. Apologies.)

mandarins of Costa Rica

costa rica mandarin fruit

If found in a grocery store in the U.S., they’d never sell. But they’re as mature and colored as they’ll ever get there. Nighttime low temperatures in Costa Rica are not low enough to turn them a uniform and beautiful orange, as they get in California. Oranges and tangerines grown in California are far prettier than those grown in tropical climates, and it’s because of our colder nights. (Read more about citrus peel coloration in this University of Florida publication.)

Our oranges and mandarins taste better too, in my opinion; they have more citrus tang whereas I find the tropical fruit insipid.

 

Taste: the conclusive criterion

Taste is subjective, of course. Yet taste is the only conclusive test of whether or not it’s time for you to pick the oranges and tangerines from your tree. My friend said he’d picked some of his tangerines and they’d tasted fine. I told him it was time to pick them then. The right time to harvest is whenever they taste good — to you.

Or your wife. My wife likes her citrus tart. I pick them for her at least a month before I start picking for myself. Oranges and tangerines get sweeter the longer they hang on the tree.

 

Growth process of oranges and tangerines

Here is how an orange or tangerine grows: In the late winter or spring, the tree flowers. Small green fruitlets form and enlarge through the summer. In the late fall, they start to change from green to yellow to orange — each variety on a slightly different schedule, and each variety a slightly different hue, ultimately. But it’s the chilly nights of November that coincide with maturing fruit to transform the rind color from green to orange, and it so happens that in the late fall the earliest of tangerine varieties also start tasting sweet. (Think Satsuma and Kishu.) Some others, however, remain tart until the spring (a full year of growing on the tree). Valencia oranges take so long to sweeten that there are two generations of fruit on the tree simultaneously, as you can see in the photo at the top of the page.

As I said, all oranges and tangerines get sweeter the longer they remain on the tree so if you taste one and it’s more acidic than you like, give the others more hang time. Eventually, they will reach their peak of sugar, nadir of acid. Their rinds will become more loosely attached to the flesh inside, making them easier to peel. But also, the pulp inside will proceed to start drying out. At last, the fruit begins to drop to the ground and rot.

What all citrus do not do, by the way, is ripen more after being picked from the tree. That is, the fruit will not get sweeter on your kitchen counter. Citrus are not “climacteric” fruit; they are unlike bananas, for example.

 

Test case: Secret tangerine

We call this our “secret tangerine” tree.

It’s an old tree that continues to survive and produce fruit in an unirrigated far corner of our property. We don’t know the variety; we didn’t plant it. But over the years, we’ve discovered that it tastes good after all of our other tangerines, about the same time as our Valencia oranges. Still, every year, we go through the “pick and taste” routine until we really start the harvest. Here at the end of spring is that time, my children and I are very happy to report.

 

Harvest charts

The good news is that oranges and tangerines do not transform in flavor very fast. They don’t have a two-week window of good eating like some peaches, for example. If you harvest citrus and like the taste, you don’t need to pick them all within that week, lest they rot and be wasted. All varieties that I know of “store” on the tree for months.

Which months? If you know the variety name of your fruit, you can get a rough idea of when to pick the fruit by using some of the harvest data within the University of California, Riverside’s Citrus Variety Collection.

Or check out this chart from Four Winds Growers, located in Northern California.

And here is an amazing, fancy chart that I made of the harvest times of the varieties that I grow in my yard (I’m in inland San Diego County):

Orange and tangerine harvest chart Southern California

Maybe you have one of these varieties too. All the while, remember that your tree is not going to mature its fruit at exactly the same time as another in another location — even if it’s the same variety. Your yard’s micro-climate is different.

For reference, in inland locations where it heats up more as well as earlier in the year, harvest dates are earlier compared to locations close to the beach. So my mandarins taste sweeter before yours in Oxnard do. Yet, mine will become over-mature long before those in Oxnard.

In addition, certain oranges and tangerines may never get as sweet as you hope if you live in sight of the ocean. I occasionally pick navel oranges from trees growing at the Salk Institute at the University of California, San Diego, near the Torrey Pines golf course. Those oranges are always so bland that they are barely worth eating.

The weather every year is also different. No two years will have the exact same harvest dates. My Valencia oranges taste excellent here on June 1, 2018 whereas they usually reach their peak flavor at the end of June. This past winter was extraordinarily warm.

What I like to do for my orange and tangerine (and all other fruit) trees is associate the harvest season with a birthday or holiday. Come to think of it though, I only use a version of this strategy for my Valencias. In my mind, I can never forget when to pick them because I grew up swimming in my grandparents pool during the summer and taking breaks beside one of their Valencia trees getting sweet, sticky juice all over my face, chest, and hands.

 

You might like to read my posts:

Oranges and mandarins fresh off the tree almost all year

When and how to prune citrus trees

Don’t spray for citrus leafminers

When to pick avocados