From the CRFG Fruit Gardener Vol.27 #5 1995


To Grow Bananas

Alice Ramirez

Yes, bananas can be grown outdoors in Southern California, but too many people still believe otherwise. Eph Konigsberg, in a recent talk to a Foothill chapter meeting, explained why that commonly held belief persists and why it is wrong.

Often, through ignorance, we fail to meet the needs of our plants, and when they fail to thrive, we blame the climate. Sometimes, people unknowingly plant an ornamental variety that would never produce edible fruit, then become convinced that our winters are too cold and our summers too dry for bananas.

Eph related a typical mistake he made with his first few banana "pups," as the sprouting root chunks are called. He put them into the ground in a narrow stretch between two fences and even nicknamed this patch "banana alley." The location was perfect, he thought, because it had plenty of sun and shelter from winds that might otherwise tear the large, fragile leaves. To his surprise, those banana plants completely failed to thrive. Those he planted in other areas grew and produced fruit, but not the first ones.

He finally learned that bananas stop growing if the soil temperature drops below 680F. The plant wants sun on its leaves, of course, but to thrive, the roots need to be warm. His arrangement had shaded the soil, keeping its temperature too low. The easiest way to maintain warm soil is to situate banana plantings in an open, sunny location. Eph’s best results came with those he had located against a south-facing wall at the top of a gentle slope.

Planting the Pup

To plant, simply stick the pup into a hole you’ve dug in the ground, then back-fill. Sandy loamy soil works best, but Eph has harvested bananas from plants growing in other soils—as long as their roots could be kept adequately warm.

If planting more than one variety, leave at least 6-8 feet between plants. Otherwise, as they spread, they will form a clump of hard-to-distinguish varieties. Second, putting them too close guarantees that they will be competing with one another for nutrients. The plants themselves will survive, but they will produce less of that delicious fruit.

If you discover too late that you have located your banana plants too close together such that one of them (typically in the middle) is failing to thrive or is sickly, dig a trench between the more aggressive plant(s) and the one(s) needing help. This will create a barrier between the roots of the more aggressive plant and the weaker one. Once the trench is dug and the roots cut, back-fill it with the soil previously removed. Using his trench method, Eph finds he can plant his banana plants 5-6 feet apart. (He says this method will work for any overcrowded grouping of trees except for jujube, which tends to send up new plants from the cut roots.)

Eph cautions potential banana gardeners to be careful about planting banana pups— or any other seedlings—harvested out of someone else’s soil. Oak root fungus is pretty much omnipresent in Southern California. If you know your own land is fungus-free, abstain from taking someone else’s banana plants, and possibly avoid infecting your own soil. Buy sterile pups from a commercial nursery instead. Although the fungus may not harm your bananas, it could cause problems for oaks or other susceptible plantings you might have. Someone at the meeting suggested that most fungus can be gotten rid of by dipping the roots in a weak Chlorox-water solution before planting. This method might very well work, but no one present knew whether it had really been tested on bananas.

Bananas Like Potassium

Inadequate fertilization, whether from overcrowding, neglect or ignorance is another reason why bananas often fail to produce fruit in our climate. Potassium is a key nutrient to the success of any banana plant. Commercial growers will chop up spent banana plants and use them as mulch, thereby returning potassium to the soil. This may be too unsightly for residential use. Eph himself uses standard citrus fertilizer, such as the Bandini product, with a side dressing of some high-potassium product. Any reasonably good garden center will offer choices.

Eunice Messner, a successful banana grower present at that meeting, highly recommended organic methods. In her experience, bananas respond especially well to generous applications of compost and other strictly organic sources of nutrients. Whatever method the banana gardener chooses, the key word should be generosity. Bananas are heavy feeders. They also respond well to mulching.

Importance of Soil Temperature

Bananas fruit once they have developed a certain number of leaves, depending on variety (12-20). The timing of leaf output and stalk production depends upon the soil temperature. In the tropics, the whole process from beginning to end takes approximately nine months. Here in California, we do not have soil that is 680F or higher for nine months out of the year. A banana plant in soil less than 680F will not die. It does grow, but more slowly. To trigger bananas into fruiting more quickly, feed generously during the warm months when the temperature is greater than 680F. Toss fertilizer down and water it into the soil.

When the plant has shown all its little fingerling green bananas, cut off the large, mahogany-colored flower hanging from the stalk’s bottom so that the strength of the plant otherwise used to sustain the blossom will go into the fruit instead.

In some parts of the world, banana flowers are considered edible. Eph learned the hard way that it depends on variety. Some produce the edible flowers found in tropical cuisine; others do not. The problem is oxalic acid. Because he was curious, Eph tried all the usual methods with his banana flowers, including boiling them in three or four different changes of water. Nothing helped. Although tasting such a flower will not harm you, it can be unpleasant.

Those Bunches Are Heavy

As the bunches develop, brace the plant. This can be done in a variety of ways. Some gardeners slip electrical conduit through a length of old hose. This is looped around the fruiting stalk so that the plant’s weight is cushioned against the comparatively soft surface of the hose. The wire is then tied to a chain link fence, or to a pipe or 2x4 board anchored securely into the ground. Others create more elaborate and aesthetically pleasing constructions. The goal is to keep the stalk from bending down under the weight of a six to nine-hand bunch of fruit, while allowing juices to flow within the stalk. (Bananas grow in layers around the stalk. Each layer is called a "hand." A bunch with nine layers would be called a nine-hand bunch. It can weigh 50+ pounds.) The garden hose method will leave a dent in the stalk, but the damage is only aesthetic. You are still able to harvest good bananas.

If you find that cool weather is approaching and your bananas are far from ripe, try a popular method of protecting them and cover the stalk with a blue plastic bag. Just pull it up around the bunch and tie it in place. This method is used by Richardson’s Seaside Banana Garden in Ventura County, California’s only commercial banana grower. It has also been adopted by many other banana growers, although others consider it unnecessary.

Bagging your bunches serves a number of purposes. It holds in the available heat, which is important during cool weather. Also, since bananas give off ethylene oxide as they ripen, bagging keeps that gas close to the fruit, which in turn accelerates ripening. It prevents fruits from developing blemishes and serves as a barrier to keep out tree rats and other pests that like to feed on bananas.

A bunch ready to be harvested will have reached its full size, will have achieved its full yellow (or red or blue) coloration and will have rounded out. (Immature bananas have an angular geometry that softens as the fruit ripens.)

After the Fruit, What?

Many people do not realize that after each stalk gives forth its fruit, its banana-producing days are over. If you go driving in Southern California, you often see banana plants in huge groupings. They are not being fertilized adequately, they are overcrowded and they do not produce fruit.

Eph points out that bananas behave like grassy weeds. While the original plant sends up a stalk, it is also sprouting "pups," outgrowths from the base. Each planted root section will sprout its own pups. These pups, in turn, sprout stalks of their own as well as new pups, which in turn... If you fail to control this process, you will end up with a small, crowded forest of non-producing plants that compete with each other for a diminishing supply of nutrients.

The commercial practice is to cut off a harvested plant’s stem about four feet above ground, enabling the remaining juices to go down and sustain the main plant. A few months later, dig out some of the root clump, leaving two to three pups at the most around the banana plant. If you intend to replant any of these culled pups, the digging-up and replanting should occur fairly soon after you cut down the parent.

(Glenn Young, chairman of the Foothill chapter, uses his own wonderfully direct method of harvesting the fruit and saves an entire step in this process. Since he does not want to climb ladders to cut down heavy bunches of ripe bananas, and since he knows that the stalk will have to come down anyway, he simply cuts off the stalk while the fruit is still attached, and lets the bananas come to him. Eph prefers the conservative approach, planting only dwarf or

semi-dwarf varieties.)

Everyone who grows bananas stresses the importance of wearing old clothes, or else dark brown ones, when cutting down, digging up, or harvesting from banana plants. The juice, when it comes out, appears clear, but leaves a dark brown stain on contact that never goes away.

Eph sees no reason why bananas cannot be grown or fruited indoors as long as the requirements for heat and light are met, but outdoors, at least in many parts of California, frost is not an insurmountable problem. If a cold frost occurs, the leaves will all blacken but often the stalk remains green. Eph remembers a time when freezing weather hit a plant that had some good sized but unripe bananas left hanging on a completely denuded but still-green stalk. He left them there. He reasoned that since the stalk was still green, it must still be getting energy and nutrients from the root system and from the stalks of other attached plants. He was right and eventually harvested that fruit. Don’t worry about cold spells killing stalks. Bananas are a weed that will return in non-alpine parts of Southern California. Once you plant a good variety, you’ll have bananas for life.

Banana Varieties Evaluated

The evaluation that follows comes from experienced banana growers who compared some of the varieties most commonly found in Southern California. Height refers to the top of the fruiting stalk, the part that needs to be reached to cut down the fruit, not the leaves.

Dwarf Orinoco: 6 ft. Considered a relatively problem-free variety.

Orinoco Better Select: 10-12 ft Produces 40-50 pounds of bananas in each bunch. Probably the most hardy variety in our area.

Apple (aka Manzano): 10-12 ft Hears well. Pups like crazy. Fruits in approximately the 20th leaf. Fruit is smaller than the standard commercial variety.

Ice Cream (aka Java Blue): about 15 ft. Has a pithy core. Some people dislike this variety. Others like it a lot.

Dwarf Cavendish: Smallest at4 ft. Ideal for indoor planting. Some growers found it to be not overly vigorous. At least one other person maintained —that it was very vigorous. Clearly, within the limitations of its genetics, this variety is sensitive to environmental factors such as competition, heat, etc. It, like the ‘Apple’, produces a smallish banana.

Dwarf Mexican (Enano Gigante): Base of fruit stalk at approximately 6 ft. Vigorous grower. Tastes like store-bought bananas.

Raja-Puri: 6 ft. Supposed to be one of the hardiest. A lot like Dwarf Cayendish and difficult to tell them apart. —Good bananas, but not overly vigorous.

Dwarf White Iholena, var. Haa Haa: Fruit stalk begins about 6 ft. up. Fruit turns yellow long before ripe. Tends to fall over with fruit on it, so definitely needs bracing.

Brazilian Lady Finger: Stalk starts at about 15 ft. No other comments offered.