Banana Deficiencies in Hawaii

Banana Deficiencies in Hawaii

Bananas are incredible plants; their vigor and robustness make them exciting to watch as they grow. When they put out their giant flower buds, I’m always amazed! Bananas are the epitome of a tropical garden, renowned for their giant leaves fluttering in the wind, and the huge racks of food that they produce. Bananas are, unfortunately, the most difficult plant I’ve ever grown. I regularly feed them, yet they are almost always deficient in micronutrients. It’s important to recognize the different patterns of deficiencies to combat and keep them healthy. A vigorous, healthy banana will pump out a hundred pounds of fruit in a single rack! If your banana plants are not upright, robust and deep green, pumping out a leaf weekly, they are hungry, and most likely micronutrient deficient.

Williams. Large healthy leaf unfurling next to good sized rack

Iholena. Erect cigar leaf unfurling healthy

Dwarf Namwah. Deep green wide upright leaves

Dwarf Cavendish. Healthy leaf stature

Due to heavy degradation, banana nutrients are notoriously low in Hawaiian soils. Calcium, boron, potassium and sulfur are almost always low or unavailable to the plants. Luckily, this can be mitigated with a bit of care and consideration.

Maoli. Ele ‘ele

Banana Bunchy Top Virus (BBTV)

Banana Bunchy Top Virus is prevalent in all parts of Hawaii and is detrimental to the species. Sometimes deficiencies may look like BBTV. Knowing the symptoms of both BBTV and nutrient deficiencies will allow you to address the issues appropriately. Be sure to source virus free plants from a legitimate propagator. Too many times, people get plants from friends and they come with BBTV. There is no known cure for BBTV; a mat that has been infected will always carry and spread it. The main disease vector is aphids, who feed on the plants’ sap, and can quickly spread the disease from plant to plant. KILL YOUR BUNCHY TOP BANANAS! There is no other way around it, dig them out of the ground and chop up the corms and leave in a place they will die, like cement or in a trash bag out of the weather.

If you are suspicious of a banana plant potentially having BBTV, get it tested! The University of Hawaii extension offices do banana bunchy top virus testing for $12 per sample. Simply take the third leaf from the top, not counting the cigar leaf, cut it in half and cut out a 2 inch section on either side of the leaf midrib. Put in a plastic bag, label and bring it into the offices. Be sure to clean your tools with rubbing alcohol between sampling. I’ve tested many plants at the Komohana Research and Extension Center in Hilo. They have a very quick turnaround, and their results are very accurate.

Banana Bunchy Top Virus Leaf Sample

GO TEST YOUR BANANAS; HAVE YOUR NEIGHBORS TEST THEIRS! This needs to be a community effort to reduce the problem. Many people have Banana Bunchy Top Virus and do not know or do not care. Inform other people of the problem and help them test and remove their bananas. It’s almost not worth the effort for someone to sell/propagate clean bananas because the keiki will be introduced into a diseased location, a very depressing issue. We need to change this, or we simply cannot grow bananas in populated areas. We’ve already lost many of the wild banana plants to habitat depletion and pig damage; do we really want to live in a Hawaii without bananas?

References for Banana Bunchy Top Virus. Information and detailed descriptions.

Nutrient Deficiency Patterns

Once you are sure your plants do not have Banana Bunchy Top Virus, it’s time to start identifying deficiency patterns. All banana varieties should produce fat, erect cigar leaves that open into very large, wide and dark green upright leaves. The leaves should sequentially get larger until the leaf before the flag leaf comes out just before flowering.

Be aware that one or multiple deficiencies may show up at the same time.

As water is a necessity for nutrient uptake, drought may lead to deficiency symptoms, including slowed leaf emergence and bunching, even in otherwise fertile soils. It may be a good idea to confirm plants are receiving proper irrigation prior to investing time and money into soil amendments.

Certain nutrients (calcium, boron, iron) cannot be stored and moved within the banana plants’ sap; these will need to be repeatedly added in order to be continuously accessible to the plants.

Many soil amendments are known as “slow-release minerals,” which means it will take time for them to become accessible and be utilized by the plant. A number of deficient-looking leaves may unfurl before results are visible.

To cure a plant more readily, utilize a micronutrient spray along with the mineral dispersal. This will cover the short term while the addition of minerals to the soil works in the long term.

The newest leaves on the plant tell signs of calcium and sulfur, the older leaves show potassium, nitrogen and iron levels.

Remember, an entire banana mat is a single plant, check out my post on bananas for more info.


Boron is necessary for normal formation and functioning of roots and cell walls. A classic boron deficiency symptom is abnormal unfurling of leaves. Boron deficiencies are closely linked to calcium deficiencies hence the common term “calcium-boron deficiencies.” Be very careful dispersing boron, as too much can be toxic to the plant. Normal store-bought Borax is an easy solution for adding boron.

Symptoms: Leaf etching (raised streaks across the veins); light yellow speckling; crinkling or wavy leaf edges and irregular corrugations; deformed leaves (twisted, curled, buckled or convoluted).

Recommended solution: One teaspoon of borax for immature plants; two teaspoons of borax for mature plants (plants with keiki).

Calcium-boron and sulfur deficient

Boron Deficiency. Irregular corrugations

Boron Deficiency. Crinkling or wavy leaf edges

Boron Deficiency. light yellow speckling

Boron Deficiency. light yellow speckling


Calcium is necessary for skeletal development, rigidity, plasticity and hydrostatic pressure. Lacking in this mineral causes deformities indicating tissue collapse, overall weakness and is closely linked to boron deficiencies. Calcium also raises pH, enabling mineral uptake in acidic soils. Calcium deficiencies are, by far, the most common in my garden.

Symptoms: Flat, Travelers Palm look; bunched leaf stalk; leaves gradually diminishing in size and deforming, twisting, cupping, buckling and having wavy margins; newly unrolled leaves droop, unravelling slowly, weakly or incompletely, sometimes sticking together and tearing when opening; loss of rigidity in the leaf tips; marginal leaf yellowing; trunks weaken, and flower stalks lose rigidity.

Recommended solution: add limestone, crushed coral, calcium carbonate or dolomite. Mix into the soil. Use one half cup for immature plants, one cup for mature plants (plants with keiki).

Calcium Deficiency. Curled leaf tip

Calcium Deficiency. Deformed leaf

Calcium Deficiency. Collapsing trunk

Calcium Deficiency. Bent cigar leaf

Calcium Deficiency. Curled/buckled leaf. Loss of rigidity

Calcium deficiency. Non-normal leaf unfurling. Yellowing.

Calcium deficiency. Deformed/Shredded cigar leaf

Calcium deficiency. Shredded Leaf

Calcium deficiency. Bent cigar leaf


Nitrogen is an essential nutrient to all plants. It aids in the manufacturing of amino acids and proteins, promotes the production of chlorophyll, enzymes, vitamins and hormones. Without nitrogen, plants become stunted, anemic and weak. Nitrogen is mobile within the banana plant and will translocate into younger leaves. Bananas require water to absorb nitrogen, so water your plants in times of drought.

Symptoms: Stunted plants produce few leaves; older leaves turn chlorotic (yellow-green); bunches appear tiny; overall weakness; vibrant pink or purple leaf stalk wings that are not typical to the cultivar; weak roots; few or no keiki.

Recommended solution: Spread nitrogen fertilizer six to twelve times annually. We use Organic Nutri-Rich Chicken Manure Pellets 4-3-2 with Calcium 7% monthly, utilizing five to six cups per mature plant. Any animal manure will work as long as it’s properly composted.

Nitrogen Deficiency. Dwarf Brazilian/Dwarf Apple. Pink leaf margins. Yellowish lower leaves


Potassium is vital for growth, overall health, disease prevention, fruit production and quality.

Symptoms: Browning of leaf margins; premature and rapid yellowing of leaves; slow, stunted growth; fewer leaves coming out at an increasingly slow pace; general plant yellowing; maroon patches on leaves; skinny trunks; tiny racks with small, underdeveloped fruit; midribs of older leaves may be broken at one half to two thirds their proper length; Travelers Palm appearance.

Recommended solution: Add wood ashes when the flower bud appears. Add Sulfate of Potash 0-0-52. One quarter cup for immature plants and one half cup for mature plants. Also add fertilizer as the flag leaf appears before budding.

Potassium Deficiency. Non normal yellowing of lower leaves


Sulfur is essential for vitamin A production. Due to Hawaiian bananas being rich in vitamin A, they need larger doses to produce properly, especially Popoulu varieties.

Symptoms: Very pale-yellow coloration in new leaves; leaf blades become very soft and delicate, and tear easily; new cigar leaves may emerge completely white.

Recommended solution: Add Ammonium Sulfate 21-0-0 or Sulfate Potash 0-0-52, one quarter cup for immature plants and one half cup for mature plants. For Popoulu bananas, add one and a half cups for mature plants.

Sulfur Deficiency. Yellow cigar leaf. Calcium-boron deficiency

Sulfur Deficiency. Yellow new leaf

Sulfur Deficiency. Yellow new leaf. Notice tearing of margin on lower leaf


Rose Beetle Damage

Solution: Hand pick beetles at night and crush or drown in soapy water. Hand picking is surprisingly effective in reducing populations.

Banana Rose Beetle Damage

African Snail Damage

Solution: Hand pick and squash or drown in soapy water. Collect at night.

African Snail Damage

Banana Corm Weevil

Solution: Obtain weevil-less propagation material, source from a legitimate propagator. Always inspect corms before planting. If a plant has weevils, learn about the correct way to clean corms to dig and remove weevils prior to planting and/or propagation. Plant in a non-infested area.

I do not have weevils nor any photos with their damage at this time. If plants fall over due to weakened roots, banana corm weevils are most likely the problem.

Properly cleaned corm due to banana weevil damage


To combat potential deficiencies, mineral fertilize along with your normal fertilizing procedures when planting. Up to four times per year (two to three times in low rainfall areas, <60 inches), add the following to the soil:

Immature Plants                                             Mature Plants (Plants with keiki)

1 teaspoon borax                                            2 Teaspoon Borax

½ cup dolomite                                               1 cup dolomite

¼ cup of Ammonium Sulfate 21-0-0               ½ Cup Ammonium Sulfate 21-0-0

Or ¼ cup of Sulfate Potash 0-0-52                  Or ½ Cup or Sulfate Potash 0-0-52

Dig bananas as large of a hole as possible when planting. Place fish scraps and compost in the bottom of the hole. Plant them deeper than their rootball. Fertilize with nitrogen monthly. Pee on them regularly. Spray micronutrients twice monthly. Apply composts and mulch thickly and widely around the base of the plant as often as possible. Literally hill them as you would potatoes, trunks will not rot from contact with soil/mulch. Do not remove leaves until they are completely brown. The plants may still be utilizing those leaves and translocating nutrients. Manage a few delicious varieties intensively; resist the urge to mass plant them. Understand they are difficult to manage properly, which is essential to reduce the spread of BBTV. (Don’t get in over your head!) Test your banana plants for BBTV and share them with others committed to stopping the spread of the virus.

All your efforts won’t be fruitless! Watch the plant pump out larger racks than you’ve ever seen!

Dwarf Maoli

Dwarf Namwah

A lot of my information came from the amazing book: The World of Bananas in Hawaii: Then and Now by Angela Kay Kepler and Francis G. Rust. For a much more detailed and in-depth discussion of bananas in Hawaii including varieties, lore, recipes, nutrients, deficiencies, diseases and pests, check it out!

Citation: Kepler, A. K. and F. G. Rust. (2011) The World of Bananas in Hawai’i: Then and Now – Traditional Pacific & global varieties, cultures, ornamentals, health & recipes. Pali-O-Waipi’o Press. Haiku, Hawaii.

Happy Gardening!

Banana (Musa Spp.)


Banana, Musa spp., plantain, mai’a, and known by other names, is another extraordinary tropical or subtropical plant. There are two main ‘types’ of bananas; there are the cooking bananas and the dessert bananas. Bananas come in many shapes, sizes and varieties, being over 300 known domesticated varieties! They are large herbaceous plants from 6-35 feet tall. The life cycle from small plant to mature fruit takes from 9-18 months depending on variety. Bananas grow in clumps producing new herbaceous stocks from common underground corm and roots. Once a stock has flowered it will cease to put out new leaves and use up the last bits of its energy producing the fruits. Once the plant fruits, and is ready for harvest, you cut down the entire stock and the next generation from that corm will have already sprouted, continuing the life of the plant. Not only are the fruits edible but also the flower bud and the center of the stem is too. The leaves are used in various cooking methods as wrappers for steaming or baking other dishes, and the leaves are also used as biodegradable plates. The plants can also be used for mulch, thatching, livestock feed, clothing, containers, twine, medicine, dye, turned into alcohol, vinegar and wine. Wow! What a plant.



Domesticated bananas do not produce seeds, so the only way of propagation is from suckers, also called pups. To propagate you take a sharp shovel or machete and cut or separate between ‘mother’ stock and smaller plants. Once removed you could let it dry for a few days, to reduce rot, or plant it right away. If transplanting, remove the leaves so the plant can focus on rooting. If you do not plan on planting bananas in another location, you could let the bananas do all the work and reproduce in one continuous place for years, thinning out, as you feel necessary.


Find pup to transplant


Use sharp shovel to remove pup from mother corm


Removed pups

Another example


Find pup to transplant


Use sharp shovel to remove pup from mother corm


Pull out once removed


Removed Pup


Root ball ready for transplanting



Find place to transplant. Dig hole.


Place plant in nutritious soil. Mulch


Plants can fruit all year long, so with careful planning you could have harvestable bananas throughout the year. With proper maintenance an original bunch of a single banana plant could last up to 50 years! Bananas are heavy feeders, meaning they take up lots of nutrients. Before planting adding rotted manure or compost to planting area is necessary. I like to grow clovers (perennial peanut would be better) around them so they also have a continuous source of nitrogen for their life. Adding mulch and nutrients as you can. Removing dead leaves helps prevent disease, and the leaves are a great source of mulch, or ‘carbon’ in your composting system.

Bananas thrive in full sun, but will grow in partial shade, and prefer some wind protection, as high winds tend to shred the leaves, making photosynthesis more difficult. Bananas need a ton of water!

Harvest your banana rack when the lines of the fruit have gone from rigid lines to smoothed roundness. Another key to look for when to harvest, is when a single fruit has started to yellow, or turn the color of ripe fruits per variety, as the rest of the rack will follow quickly. Look at the highest fruits as they mature first. Banana sap will dye and create unremovable stains on clothing, so when cutting down a rack and stock be sure to wear appropriate clothing. When I harvest a rack I cut the stem of the rack a foot above the tops of the fruit so there is somewhere to tie a rope to while the rest of the fruits mature. Rumor has it, that if you hang your rack upside down, the mature fruit from the top of the rack will fall first and will not harm the other maturing fruits. From flower production to harvest-able fruit is about 3 months, unless it is during the dry season, then it will take longer.

Harvest is simple. However, you may need multiple people if it is a tall plant. Cut the stock of the fruiting plant a few feet from the ground. Cut slowly so you can watch the stock bend with the weight of the rack, yes they are heavy! Once the rack has lowered enough gently, they are fragile, hold the rack while someone else cuts the stock of the rack away from the rest of the plant. Freeing the rack you may hang it up immediately or cut the rest of the plant down. Once you cut the rest of the plant down, you may chop it up for faster decomposition, or simply place it somewhere you want to let it decompose. Its full of great nutrients, add it to a bed, under the soil, in a compost pile, or anywhere else.

I like to hang my racks from the house in the shade to drip onto the ground for a few days. Once the dripping has stopped, I move the rack into a screened area, or put some kind of netting over it, so fruit flies and birds don’t get the harvest.


Make sure your rack is ripe


Cut the stock of the fruiting plant a few feet from the ground slowly so it bends with the weight of the rack


Once the stock has bent far enough. You cut the stock of the rack a foot from the top of the fruit


Hang somewhere safe


Cut down plant

Tip: You could literally google about bananas forever. They are used in numerous ways in permaculture design too, due to their necessity for nutrients, use in banana circles, composting pits, polyculture designs and guilds. A perfect permaculture plant. The information is endless, follow whatever methods you desire, as there are many ways to grow and harvest bananas. Just grow them! You only have one day of work for the entire plants life-cycle and that’s during the harvest!


This is where things get interesting. Did you know that bananas are grown around the world mostly for its cooked starchy fruits and not for raw dessert varieties? Fruits are very versatile; you can cook them like potatoes in many ways, in soups, curries, mashed, fried, used raw in milkshakes, smoothies, breads or cakes. You may cook them when green, yellow, or brown depending on the texture you’re looking for and the recipe followed. Dessert varieties may also be cooked but tend to lose their texture with cooking, making them mushy. And cooking bananas may be eaten raw, but having a high starch content making them less desirable. Unripe fruit may be dried and ground into meal and used for a beverage like coffee.

Flowers for eating are cut as soon as the final bud has opened creating the final hand of the rack. Then the outer leaf sheathes of the bud should be pulled off with the blossoms until the pinkish white heart is revealed. Then cut the bud lengthwise into four and prepare for specific dish. Apparently the heart is reminiscent of artichokes. I have no experience with cooking the flower buds yet, but next flower that grows I will try it out. So research some recipes and try it out for yourself, apparently different varieties flowers taste different, some tasting better than others and particularly cooking bananas flowers are better textured and flavored.

Where to obtain planting materials

Obtaining banana plants can be costly. Here in Hawaii the prices seem to range from $5 to $90+ depending on rarity. What a range! Good varieties to start off growing that grow hardy and quickly are the common apple and dwarf Brazilian varieties. Some varieties produce more keikis or suckers than others, so growing these varieties could get you established with a crop while your other varieties are establishing themselves. Your plants will grow for many years, so obtaining the initial plants is the only cost investment. If you can find a friend or abandoned banana plants you can propagate for free.

My Garden

When I moved into this property there were two clumps of bananas already growing and I planted more varieties and I am waiting for them to fully establish themselves. So for this section I will focus on my friends garden, which has much more established banana plants. He allowed me to help him out with harvesting and propagation and using his garden for a blog entry. His bananas are going off right now, tons of fruits growing, flowers opening, harvestable racks, and natural regeneration or propagation.

He has planted numerous banana varieties around his garden plot as the border, mixing: taro, sweet potato, sugar cane, bitter melon, liliko’i (passion fruit), cassava, mulberry, pigeon pea, patchouli, comfrey, turmeric, tomato, avocado, papaya, sunflower, ginger, coleus, squash, ti and burdock (yes that’s just his border around his garden!!!). There is a small fence around this border to prevent animals from entering, and uses vetiver, Chrysopogon zizanioides, around the fence to prevent grasses from entering the garden. Then within this border of plants he has his normal crops growing in their beds, peppers, tomatoes, fennel, strawberries, carrots, lettuce, kale, roselle, and rosemary. Allowing a large production of foods from a small space. Outside of this section he has an established orchard giving him tons of fruits throughout the year, and also a shade house for seedlings and tender sun-sensitive plants. His garden is less than a year and a half old and you can see its lushness and abundance. He started small, in a maintainable space, learning tropical gardening and seeing what works at his location and has been quite successful! His garden is the perfect example of what every home gardener should have, an amazing abundance of fruits and vegetables of starches and nutrient rich plants stacked in a small space.


Since he has different crops growing from me and at different stages of growth, we are able to share our abundance and reduce wastes. Making connections and bartering is necessary in a self-sufficient lifestyle.

Happy gardening!