This page is meant to be very basic advice on how to plant and care for your banana plants in Hawaii, particularly in the Puna district.
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Banana plants love 3 things: water, sun, and food! Providing plenty of each makes all the difference between plants that survive and plants that thrive.
Once you have your plant, also known as a “keiki” or “pup” be sure to keep it in full sun and keep it well watered until you plant it. Banana plants can survive in pots, in some cases long enough to flower. Still, you should plan to get your plant in the ground soon so it can take off!
Find a spot in full or at least 1/2 day sun. Dig a hole bigger than the pot your plant is in. At least twice as big is ideal, but bananas have a way of finding room to grow, even in lava rock.
Mix soil or cinder soil with organic matter (free County mulch, manure, etc.) and put into the hole below and then around your plant.
You must spread mulch as far around it as possible. Bananas tend to send out roots near the surface, tens of feet from the plant. The idea is to keep that entire area moist with enough mulch so that roots can absorb water and nutrients without drying out.
Your newly planted banana may seem like it’s not growing for months. This happens frequently, as it is spending energy on developing new roots before it puts out huge leaves. You may even see the leaves on your small plant turn yellow and then dry up. This happens occasionally, usually followed by new growth coming out of the corm (root ball). If you see either signs of stress, make sure it is not constantly over-saturated, or it may be rotting. As long as there is some green and perhaps new small keikis coming up, don’t give up hope.
If you are not growing 100% organically, bananas benefit hugely from handfuls of banana fertilizer such as 13-3-37 or 10-5-40. These can be found at BEI and Garden Exchange in Hilo. 50 lb. bags are under $30 and don’t go bad. Ideally, fertilize every 4-6 weeks, and possibly more frequently during periods of very heavy rain. The high number is potassium, which is critical in having good sized bunches of well filled in fruit. If you are growing organically, you can even purchase 0-0-50 organic sulfate of potash from BEI. Bananas are heavy feeders. If growing organically they are going to need lots of organic matter frequently, and using organic sulfate of potash is still strongly recommended.
Bananas need watering, especially during dry spells and in dryer areas. Bananas can handle an inch of water per day! If you live somewhere with less than 365 inches of water per year (virtually all of Hawaii), they will respond well to watering. However, the soil should be well drained so that roots or the whole plant don’t rot. In Puna, this is not usually a problem with our porous “soil.”
If you are a lazy gardener, there is still a good chance that you will get regular fruit if you are in Puna, especially with Dwarf Apple bananas. As long as you keep the plant well mulched and try to feed it some type of fertilizer every once in a while, you’ll still likely get regular fruit!
Are any of the fruit on your bunch turning yellow? If so, it’s ready to harvest!
It is easiest to use a saw, not a machete. For short types, just cut the bunch stalk about a foot above the top fruit.
For tall types, slice the trunk 3 feet from the ground on the side opposite the bunch. The whole trunk and bunch will begin to collapse. When it is low enough, cut the bunch stalk like you would a short type.
The plant you just harvested from is done. It will never grow more or produce more fruit, but it should have already put out new keikis. Cut the entire trunk off 3 feet above the ground. With Apple bananas, you can usually just let the cut trunk top decompose and feed the growing plants (though you will reduce corm weevils by not doing so). After a couple months, you can dig up the dead trunk that remains in the ground and dispose of it.
Remove all leaves that have no green on them or remove them when less than 50% green. They should be disposed of or composted away from banana plants for highest fruit yields.
Hawaii growers have to be wary of Banana Bunchy Top Virus. If your plants show signs of it. Please be very careful to completely remove and dispose of the plant. Spray soapy water on the plant first or all the infected aphids will fly away when you try to kill it. Please never sell, buy, or try to grow bananas showing signs of bunchy top!