We recently ordered a couple of banana plants and while one is doing well, the other isn’t growing. I tried finding out why, but I couldn’t find a good answer online. So, I did some more research. Here’s what I found.
Banana plants won’t grow if they have improper watering, sunlight, nutrients, or are affected by transplant shock or root-binding. Ideally, only water banana plants when the top 2-4 inches of soil is dry, provide 6+ hours of sunlight, and apply a quality fertilizer or compost as directed.
While this helps explain why banana plants won’t grow, how can we tell which issue is causing it, and from there—how can we fix it? Let’s take a closer look.
When banana plants are under-watered, their leaves stop growing, which then curl or droop to conserve moisture. But if left without water for too long, the leaves begin to brown and die.
So, what’s the best way to water banana plants?
Only water banana plants when the first 2-4 inches of soil is dry. You can check this by pushing a finger into the soil. The goal is to have soil moisture similar to a wrung-out sponge. Water at least 2 feet deep as most of the plant’s roots are found within this depth.
Additionally, provide banana plants with 2 inches of compost and 4-12 inches of mulch. This amount might seem excessive, but banana plants evolved in forests as understory plants and had plenty of fallen leaves and branches to maintain soil moisture and use as nutrients.
Compost not only provides valuable nutrients but feeds beneficial soil life and increases the soil’s richness. Every 1% increase in the soil’s richness or organic matter leads to 20,000 more gallons of water held per acre (source).
Mulch provides the banana plant with dramatically reduced soil evaporation, soil temperature regulation, and nutrients once the mulch is broken down. Again, mulch is a key element for banana plants and food forests!
If your banana plant is still getting too hot and dry after providing compost and mulch, consider giving it partial shade from the hot afternoon sun.
Over-watered banana plants are often stunted in growth and show other symptoms such as leaves drooping and yellowing.
These issues are caused by the plant’s roots suffering from a lack of oxygen in the soil. Over time, this leads to root rot (a disease caused by a water mold). And if left without treatment, this will likely lead to the banana plant dying.
The good news is that over-watering can easily be fixed.
Because over-watering is most common in soils with poor drainage, let’s take a look at how we can amend the soil for banana plants.
Even if you’re watering your banana plant correctly, over-watering can still occur if its soil has poor drainage. This is especially common for banana plants that are planted in heavy clay soil or those that have collapsed soil (common with potted plants).
Here’s how to check for poor drainage and how to fix it.
Planted Banana Plants
Check your banana plant’s drainage by digging a nearby hole 1-foot deep and wide, filling it with water, and measuring how quickly it drains. Just make sure to dig the hole outside of the plant’s drip-line (canopy). If the hole drains slower than 2 inches per hour, it has poor drainage.
If your banana plant is already planted in the ground, it’s tricky to amend its soil as digging the plant up will likely result in transplant shock—potentially stunting or killing the main plant. However, since banana plants grow quickly (often fruiting after 9 months) you can always transplant a “pup” to soil that is already amended.
For the main banana plant, amend its soil by applying 2 inches of compost under the plant’s drip-line every 1-2 months. Over time, the compost will work its way down into the soil, amending and improving its drainage.
While you can also provide some mulch, too much will prevent any waterlogged soil from drying. So, it’s best to avoid using mulch at this stage if possible.
On the other hand, if you have not yet planted your banana plant (such as if you just bought it from a nursery), and your garden soil is draining poorly, it’s best to plant the plant on a mound of soil or in a raised bed.
You can even plant several banana plants in a mound together in what’s known as a banana circle.
To help with this, check out my other post for more information on working with clay soil and planting in mounds.
Once the soil is well-draining and feels like a wrung-out sponge, proceed with providing compost and mulch as directed in the “under-watering” section above.
Potted Banana Plants
If you have a potted banana plant, you can check its drainage by the feel of the soil. If the soil is sopping wet for more than 1 hour after watering, the soil needs to be amended. Again, the goal should be similar to the moisture of a wrung-out sponge.
To amend a potted banana plant’s soil, simply repot it with fresh potting soil. Since the pot naturally confines the plant’s roots, there’s much less of a chance of transplant shock (compared to digging mature banana plants out of the ground).
Even if your potted banana plant is waterlogged enough to have root rot, repotting will most likely save it. This is what I did to my Kaffir lime tree when it had root rot, and it made a full recovery and has been thriving since!
Remember to repot your banana plant into a larger pot every 3-5 years as the roots will need more room to grow. The exception to this is if you’re growing a dwarf banana plant.
3. Lack of Sunlight
Generally, banana plants require at least 6 hours of sunlight to photosynthesize properly. Without it, their growth is halted. Additionally, their leaves turn yellow from the lack of chlorophyll and they’re unable to develop sugars for the plant.
Over time, this low energy leads to the plant’s declining health, which eventually dies.
Tips to Increase Sunlight
- Plant the banana plant in a south-facing direction for maximum sunlight (north-facing if you live in the southern hemisphere)
- Plant the banana plant along a south-facing wall to reflect more sunlight and heat onto the plant (some heat from the wall even persists into the night).
- Prune overstory trees that are blocking the banana plant’s canopy from the sun. Additionally, cutting down the main banana plant (and turning it into mulch) after it has fruited is common practice as it allows its pups to grow in its place. For this reason, many growers have pups at different stages of growth.
4. Lack of Nutrients
|Entire leaf is pale or yellow
|Dark green veins, rest of the leaf is yellowing
|Broadly pale leaves, foliage color looks mottled or smeared
While different deficiencies have different symptoms (shown in the table above), a balanced fertilizer or compost contains sufficient primary and secondary nutrients for banana plants.
Banana plants that have imbalanced nutrients often get deficiencies—which leads to issues in growth. These deficiencies are also often caused by outside factors such as poor soils, leaching, and other conditions such as improper pH.
For example, nutrient leaching occurs when the soil’s nutrients seep too far down, out of reach of the plant’s roots (beyond about 2-3 feet). This normally happens when soils have too much drainage or are over-watered. Sandy soils in particular are notorious for their leaching quality.
Since banana plants are tropical plants, and are often grown in sandy soils, nutrient leaching is fairly common. However, an easy way to prevent leaching is by using mulch to retain the nutrients in the soil for longer (mulching other banana plants that have finished fruiting is a great method).
But what happens if you need to use fertilizer to address your banana plant’s deficiencies?
The Best Way To Fertilize Banana Plants
The two main ways to fertilize your banana plants are with fertilizer or compost. If you choose a store-bought fertilizer, aim for a balanced NPK (nitrogen, phosphorus, and potassium). For example, use a 10-10-10 NPK. For compost, choose one with the highest quality and freshness if possible.
However, while chemical fertilizers have nutrients in quantity, they typically don’t have quality nutrients.
Even though chemical fertilizers might be sufficient over the short term, over the long term they often short-circuit the nutrient exchange between the plant and its beneficial soil life (such as mycorrhizal fungi). This leads to dry and dead soil (AKA dirt) and overall decreased plant health.
Mycorrhizal fungi promote many aspects of plant life, in particular improved nutrition, better growth, stress tolerance, and disease resistance.Department of Biology, University of Fribourg, Switzerland
On the other hand, compost provides more than sufficient nutrients, increases water retention, and promotes healthy soils. Many gardeners are even finding that compost is replacing their fertilizers. When selecting compost, choose one of quality and freshness as its beneficial soil life and bacteria will still be alive.
Either route you take—you can see my recommendations for both compost and fertilizer on my recommend fertilizer page.
While nutrients are important, they’re nearly useless if the soil does not have a proper pH. This is because a slightly acidic pH is necessary to dissolve the nutrient solids in the soil and make them accessible for the plant’s finer roots.
Fourteen of the seventeen essential plant nutrients are obtained from the soil. Before a nutrient can be used by plants it must be dissolved in the soil solution. Most minerals and nutrients are more soluble or available in acid soils than in neutral or slightly alkaline soils.Donald Bickelhaupt, Instructional Support Specialist, Department of Forest and Natural Resources Management
Banana plants need a soil pH of 5.5 to 7.0 (source).
Two good ways to check your soil’s pH are either by using a pH strip or a pH meter. I prefer using a pH meter since they’re affordable and easy to use. To see which pH meter I use and recommend, check out my recommended tools page.
If you find that your banana plant’s soil is too alkaline (above 7.0) you can add acidic amendments such as coffee grounds, sand, and peat moss. On the other hand, if your banana plant’s soil is too acidic (below 5.5), add alkaline materials such as wood ash, charcoal, or lime.
Additionally, cold and/or wet soils are not good at promoting nutrient uptake as the banana plant will either be dormant during the cold or too stressed in wet soils.
5. Transplant Shock
If your banana plant was recently planted or repotted, and it hasn’t been growing since, it’s likely due to transplant shock. Transplant shock occurs when a plant is exposed to a new environment and has to establish a new root system.
Avoid transplanting banana plants unless necessary as it can take up to 1 year for recovery.
To help avoid transplant shock, I like to plant with the following steps in mind:
- Have the new ground (or pot) prepared
- Remove as much of the plant’s current topsoil as possible, without damaging the shallow roots
- Grab the base of the plant’s stem and wiggle lightly
- Using your other hand, scoop up and support the rootball
- Lightly place the plant in the new ground (or pot) and fill it in
- Make sure the soil is at the same level on the plant as before
- Apply 2 inches of compost and 4-12 inches of mulch to the top of the soil
- Water generously and add more soil as needed
6. The Pot is Too Small
Banana plants stop growing if their roots become limited or bound. Naturally, this is common for potted banana plants. As their roots are physically blocked from obtaining more nutrients and water, the banana plant itself will become stunted.
Luckily, banana plants recover when they’re moved to an area with more soil.
A good way to check if a banana plant is root-bound is to inspect the pot’s drainage holes. If roots are growing out of them, the pot is likely too small.
Additionally, you can begin to lightly remove the plant out of the pot and see if the soil is being held in one, large piece (much like the photo above).
If your banana plant is root-bound, repot it into a larger container with fresh potting soil. This ensures the plant has enough water, nutrients, and space to grow roots. As well as continuing to grow leaves (and fruit depending on your variety).
How to Make Banana Plants Grow Faster
You can make a banana plant grow faster by providing the proper amounts of water, sunlight, nutrients, and space. Since banana plants are natively from the tropics, you may even find they do better in humid environments.
A good way to provide more humidity for your banana plant is to place a humidifier near it (for indoor plants) or use a fan with a mister (for outdoor plants).
For our troubled banana plant, we found that it needed more mulch and water to grow since we’re in a drier climate. We’ll keep an eye on it for now, but to make it even more comfortable, we may even add an outdoor fan with a mister!
If you’re looking for beneficial plants to grow alongside your banana plants, see these banana plant companions I wrote about in another post. Also, check out how Pete Kanaris uses Mexican sunflowers (Tithonia diversifolia) as a green manure in the video below!