Growing Bananas

Banana - Enano Gigante Photo
The banana at the right is an Enano Gigante, which is Spanish for giant dwarf. The dwarf part of the name comes from the height of the fully grown banana, about 8 feet (regular bananas can be 20 feet tall), while the giant part appears to come from the size of the leaves, which are extremely broad. This plant is on the East side of the house and was planted in March approximately 15 months before this picture was taken. Originally there was only one stalk.

Bananas grow very well in Phoenix, but need lots of water. They like sun and heat but do appreciate some afternoon shade during the hottest months. Depending on where you live in town and how cold a winter it is they will probably get nipped by frost or outright frozen but are known to pop up again in the spring. Wind will shred the bananas leaves and in the case of tall bananas can blow them over, so planting next to walls and houses is beneficial.

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If it freezes every year you won't get bananas because it takes about 18 months for them to flower. Unless you live in a low spot or next to a mountain your bananas will make it through the winter some years. Nevertheless, you will be happiest if you plant them for the way they look rather than for just the fruit. If the fruit is exposed to a lot of hot sun it is likely to turn black and spoil before it gets fully ripe. So it is best to plant somewhere that this situation can be avoided or to try to create artificial shade over the bunch when it is on its way to ripening. As for the flavor of the fruit grown here, one can expect to get bananas as tasty or more tasty than those purchased in the super market.

Note: A photo history of growing a Rajapuri Banana can be found in the gardening forum.

Banana bunch Fruit
There are actually many varieties of bananas in the world. This might be a surprise to some Americans since the super markets usually carry only one variety. Not all bananas are white on the inside. In fact there is a delicious variety in South America referred to as the "island banana" that is pink inside. Furthermore, this banana is also very dense and filling compared the U.S. supermarket banana. See the links below for listings of banana varieties.

The bananas on the left are on the Enano Gigante pictured above. The plant bloomed in late June and it only took two weeks for the bananas to reach the size in the picture, approximately 4 inches. The male banana flower can be seen at the bottom of the stalk, while the female flowers become the bananas. The flower nectar smells like a banana peel. Bananas are self fruitful, so there is no need for cross pollination.

Interestingly, bananas are not really trees. They are herbs, meaning that the stalk is really not an individual plant but a stem of a larger organism. The core of the banana is its root system, which is called a corm. Once a stalk has produced fruit it dies and should be cut off. As can be seen, little bananas are always popping up.

Many texts suggest that to maximize productivity the number of bananas stalks should be limited to three, so any more than that should be cut. I haven't practiced this thinning and still got fruit so my opinion is that this is not necessary, at least for the home grower.

Many sources say that bananas should be harvested as soon as the first hand on the bunch turns yellow, allowing the rest of the fruit to ripen at room temperature. This appears to be the best advice for commercial banana growers because they must ship their product green, and they also have selected varieties that ripen well during shipping. I have found with my Rajapuri banana tree that they are best when ripened on the tree. I pick each individual banana when it turns nicely yellow. Also, I have found that when the fruit is ripe like this, it separates easily from the tree.

The higher the temperatures are in Phoenix when your fruit is ripening, the faster your fruit will get jelly like when ripe, yuck. You have to pick it at the perfect time when it ripens so fast. Therefore, you might want to try to time the fertilization of your bananas and thus the emergence on your flower so that your fruit will ripen in the fall rather than in the middle of summer. If your banana flowers in the Fall (see the Rajapuri history up top) then your fruit will linger on the tree all winter with very slow progress and ripen in the middle of summer. This year I will try attempting to make my banana flower mid summer. That way maybe I'll have ripe bananas in November, and then I will come back and edit this paragraph. Wish me luck. (edited 5/5/2020)

Heat Tolerance and Sun Exposure
Bananas tolerate heat fairly well but need plenty of water because of substantial evaporation from their big leaves. Also, it is likely that the edges of the leaves will scorch some time during the peak of summer no matter how much water the plant gets. A banana will probably be able to tolerate being planted on any side of the house but will be happiest (like most plants in Phoenix) on the East side. On the East side, the plant will get plenty of sun in the morning but have refuge from the scorching afternoon sun. Bananas need a lot of sun to store energy for fruit production, so keeping the plant in full shade is not recommended.

Cold Tolerance
The above ground portion of a banana will be killed when temperatures drop below freezing. By planting the banana next to the house or a concrete wall, the chances of it being exposed to freezing temperatures are reduced. The roots are reportedly killed at 22 degrees. Seeing as how it is highly unlikely that 6 inches into the ground will ever go below freezing, it is very unlikely that your banana will ever be completely killed here.

Dig a hole at least twice the size of the rootball. At a minimum, make the hole 2 feet in diameter and 1.5 feet deep. Work in a 50/50 mix of compost to soil. Be sure to mix the compost and soil as thoroughly as possible. It also is a good idea to finish with the hole an inch or two recessed so that a watering basin is formed.

Watering frequency
Bananas do well on a grass watering schedule the majority of the year. However when it's really baking hot and dry in summer, for example in June, a little extra water in addition to that schedule can do some good. During winter let the soil to dry out well between waterings, and when things are genuinely cool water much less frequently. During December and January, and possibly February I stop watering my banana plant completely. Overwatering bananas in cold weather makes them susceptible to root rot and chlorosis. These are conditions which can kill the plant, even its roots. Bananas are normally a healthy dark green, so if the leaves start turning yellow during cool weather, then further reduce watering.

Watering method
Basin or flood irrigation is recommended because it helps keep the salt in our salty water from accumulating around the roots. Furthermore, deep watering will encourage the plant to develop deeper roots, making the plant tougher when the weather gets hot and dry.

Fertilizing and Growth Rate
Bananas grow rapidly and are therefore are potentially heavy feeders. During the growing season, a banana can be fertilized every one to two months using a high nitrogen fertilizer. The reason I say "can be" is because a banana doesn't have to be heavily fertilized, but it can be if you want rapid growth. I'm fairly lazy with fertilizing my banana plant these days and it does just fine. Sometimes I forget to feed it for an entire year. :) Bananas definitley should not be fertilized during the cool time of the year when they are growing slowly. Also, in Phoenix, bananas should not be fertilized when fruiting because the fruit will turn black and spoil. Therefore, as soon as the banana flower appears stop all fertilization until the fruit is harvested, approximately four months later. Most likely this sensitivity to fertilizer is caused by the general saltiness of the water and soil in the Phoenix area.

The enano gigante pictured above was fed one gallon of liquid miracle grow flowering plant food (mixed with water as per. recommended on the instructions), once every one to two months, during the warm time of the year. The plant's basin is flooded and then the fertilizer is poured into the water. A half inch layer of mulch is maintained in the basin to help control weeds and to amend the top soil.

Interestingly, the small black specs in commercially sold banana fruits are seeds but not viable. Viable banana seeds are larger and harder and therefore not edible. Domesticated bananas are usually propagated by separating the young banana shoots from the rest of the corm. See the below links for more information on propagation.

Bananas have no significant pest problems in Arizona.

A Sample Banana Plant History In Phoenix
The following table contains the history of the enano gigante pictured above. I will not alter this history because it is all factual. However, I no longer use gypsum in my garden because it does not appear to have any benefit. I also do not use much fertilizer on my banana plant and still get at least a crop every year. When I do fertilize I use something mild like fish emulsion. The history of the Rajapuri at the link near the top is closer to how I manage my banans plants now. I actually don't pay much attention to my banana anymore. Ever since I dug up the Enano Gigante and replaced it with the Rajapuri it's a fairly easy plant to take care of.

Date Description
3/2002 Planted from container, height = 2ft
5/2002 Second stalk appears, height = 2.5ft
7/2002 height = 4ft
5/2003 Photo taken of entire plant, height = 5ft
6/15/2003 Flower
6/30/2003 Photo taken of fruit, bananas developing, stalk very bent with weight, lower stalk reinforced with stake, lightly fertilized to help plump up bananas
7/07/2003 Record high temperatures (over 110 degrees F.), banana stalk crimps above stake, bananas soon blacken and spoil
Theory Possibly, the banana needed more water in hot weather, because water helps to keep the stalk rigid. Next time I will splint the entire stalk as soon as a flower appears to keep the stalk from leaning so dramatically. I will also put a white paper cone over the fruit, to keep the sun off, as soon as they appear. A larger grove of bananas would also help to give more shade to any bananas fruiting on the inside. It also might help if the plant doesn't flower in the absolute hottest time of the year. The middle of August would probably be a more ideal time.
7/10/2003 Broken banana stalk cut.
10/15/2003 Second banana flower emerges on a new stem. Banana stalk is relatively straight but is splinted with a large wooden stake to be safe. Stake is not driven into the ground but runs most of the length of the stem below the flower.
12/6/2003 Flower is cut when 50-60 bananas have emerged above it to prevent stalk from falling. It appears that another 50-60 would have emerged.
2/15/2004 The bananas on the end of the bunch appear to be turning black. A shade cloth has been placed over the bunch even though the sun is not currently strong, and should not be a factor. Furthermore, temperatures have not gone close to freezing here for over a month so cold should not be a factor either.
3/10/2004 All of the bananas have turned black and spoiled. This leads me to believe the problem is not the weather but rather the soil. The most likely problem is the high salt content of our soil. This year I will use more gypsum to leach away the salt and see if this is effective. The bananas will still be covered when they emerge to eliminate the sun as a variable.
5/15/2004 Flower. Deep soaked the tree with Gypsum to leach the sodium out of the root zone. I will not fertilize the tree anymore until the bananas are ripe. I will not cover bananas because they are emerging right next to the North facing wall, so they will not get direct sun after 10:30 AM. Stalk will not be splinted yet because it appears to be firm.
6/1/2004 Flower cut. Approximately 50 bananas present. Stalk is showing signs of carrying the weight but is still fairly upright.
6/16/2004 Noticed that stalk is more firm after watering. Therefore, I am watering the banana 5 times a week to make sure the soil is constantly wet. Day time temperatures are 105 Fahrenheit.
9/15/2004 Success!

I actually didn't water the banana 5 times a week as I thought I would but they still turned out well. It was automatically being watered 3 times per. week and I might have given it an extra watering by hand every now and then, so it probably was watered 4 times week on average during the hottest part of summer.

The bananas were too heavy for the stalk but lacking a good way to support the stalk I waited until the bananas were actually touching the ground before putting in a support. Unfortunately, the stalk crimped some before I supported it but it wasn't damaged enough to kill the bananas. The support I used was an old umbrella baby stroller.

I did not fertilize the plant the entire time the fruit were present. I believe this was the key to success because last summer the bananas spoiled immediately after being fertilized. I also put some gypsum at the base when the flower appeared but used nothing but water after that point.

The banana bunch was hanging very close to the North side of the wall. This position might have also helped by reducing the amount of direct sun they were exposed to.

Ripe Bananas - Enano Gigante The bunch was harvested as soon as the first hand turned yellow, as can be seen in the photo below. The bananas that had already turned yellow were overripe and therefore not very tasty. It appears that they go from green to ripe extremely quickly on the tree in the Phoenix heat. The rest of the bunch was brought into the house and set on the counter to ripen. In approximately a week they were ripe and about 40% of the bunch was quite delicious. Some of the other bananas split and bruised and were less than ideal. Enano Gigante bananas grown here are smaller than supermarket bananas and somewhat creamier. The flavor is very similar to supermarket bananas.

Links to more banana information

Julia Morton      California Rare Fruit Growers

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