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Palm Fertilizer

Episode #3
Release Date: February 12, 2024

Learn what may be causing your palm trees to turn yellow, how long it can take to correct, and what to look for in a palm fertilizer.

Episode Transcript:

JULIE
On this episode of Your Central Florida Yard, join us for a discussion on keeping your palm tree healthy and green. Learn what may be causing your palm trees to turn yellow. How long it can take to correct it, and what to look for in a palm fertilizer.

ANNE
Welcome to Your Central Florida Yard, the podcast series where we explore how to successfully garden in the unique climate of Central Florida. Whether you're a seasoned gardener or just starting out, this podcast is for you. So grab your shovel and get ready to dig in. This podcast is brought to you by UF/IFAS extension, Polk County.

JULIE
Palm trees are really iconic in Florida. I think if you think about Florida, one of the first things you'll think about is a palm tree. It's actually our state tree, although that is a debatable topic. Is there a monocot and not a dicot? But they do grow into a tree form, at least most of them.

ANNE
So yes. In fact, it's so iconic that the seal of the flag of the state of Florida also includes a palm, which, interestingly, the original seal included a coconut palm and then was changed and now includes a sabal palm, which is also known as the cabbage palm, the state tree.

JULIE
So now for one of the most common questions and occurrences. What is causing my palms to turn yellow? Often people assume that their palm is being affected by a disease, but nutrient deficiencies are fairly common.

ANNE
Yeah, nutrient deficiencies can affect the appearance and the growth of your palms. Each deficiency has a unique showing on the palm, which means they each affect a different location. Older fronds versus newer fronds and similar things like that.

JULIE
Yeah. Have you ever noticed a lush green lawn with unhealthy looking palm sitting in the middle of that lawn? Well, it turns out the high nitrogen in turf grass fertilizer can actually induce or cause potassium deficiency in palms. And so speaking of these nutrient deficiencies, let's take a look at some of the most common nutrient deficiencies that you might find on your palms, what they look like and what the causes are. And so I think one of the most common is magnesium. And you're going to easily identify this when you see light yellow color on the outer margins of the older or lower fronds on the palm. And it even can get through the middle of the canopy. But those older fronds are a real indication.

And so while the margins turn yellow, you're going to notice the center of the leaves will actually stay green. And so magnesium deficiency is caused by too much potassium. So speaking of potassium, you might also notice a potassium deficiency on your palm. And you're also going to find the symptoms of this on the older leaves. I often notice the speckling on the leaves and the yellow orange color that has necrosis on the leaf tip as a very recognizable symptom.

The dead tips may also be curly, and so that'll be an indication of that potassium deficiency. And so speaking of necrosis if you're not familiar with that term that's actually dead leaf tissue. That’s often going to appear as like brown or tan tissue. And so potassium is another deficiency that is caused by way too much of another nutrient. And so in this case too much nitrogen like what you find in your turf fertilizer actually causes the potassium deficiency.

ANNE
All right. So another nutrient that your palm may be deficient in is manganese. Not to be confused with magnesium. And sometimes this deficiency is referred to as frizzle top because of the frizzly appearance. And you'll notice chlorosis, which is yellowing on the new leaves and the smaller leaves and it's most severe at the base of the leaf. And you might even see longitudinal streaks on the leaves as well.

And this deficiency is caused by a high pH in your soil. You may notice a boron deficiency. And that will always show on the new leaves. And they'll actually look kind of like an accordion. So someone's folded them up, in kind of a zigzag appearance. And so another very obvious symptom is the trunk bending or the leaves not growing in a downward direction.

And you might notice the spear leaf does not open, which is the leaf at the top of your palm. Boron deficiency can be caused by not enough boron in the soil or is easily leached through the soil, like if there's a heavy rain that causes a lot of leaching to occur, that boron might be washed from the root zone. And this can be corrected with 2 to 4 oz of soluble boron, mixed in five gallons of water and applied as a drench around the palm.

And it can take five months to see a correction of a boron deficiency. So don't think that this won't be an immediate fix.

JULIE
Yeah, and speaking of that, I think it's important to remember that correcting these nutrient deficiencies can take anywhere from six months to even 2 to 3 years. So a lot of patience is required, you know, because the palm has to regrow completely healthy fronds that are not exhibiting these nutrient deficiencies.

ANNE
I think it's also important to remember that this change is going to be seen on the new leaves. And the leaves that are already there will not be healed. So what should we look for in a palm fertilizer?

JULIE
Right. I think it's important first that we talk about when talking about a fertilizer, that fertilizer labels have three main nutrients or numbers that represent the percent of nitrogen, phosphorus and potassium in that bag or container of fertilizer. And so this is known as the fertilizer analysis or grade. And so for example, you may have heard or seen an 8 8 8 or 10 10 10.

By the way, these are not appropriate rates for applying to palms. Just an example here. We'll talk about the appropriate palm rates in just a minute. But remember different plant species have different nutrient and fertilizer needs. So we're going to talk about what is the correct formula for your palm versus you know if you need to fertilize something else make sure that you know what it requires.
 
And so fertilizer is a way that we get nutrients to the plants when those nutrients are not readily available in the soil or whatever medium, you know, that plant might be growing in.

ANNE
And that leads us into soil pH. So nutrient availability in the soil can vary with different pHs. And the pH is a measure of how acidic or alkaline the soil is. And so acidic would have a lower number and the alkaline would have a higher number, when looking at pH.

JULIE
So as you ask what exactly should we be looking for in a palm specific fertilizer?

ANNE
The first thing to remember with applying fertilizer for any plant, particularly with palms, is to know your species. So what type of palm are you needing to add that fertilizer to? And currently, unless they're exhibiting any nutrient deficiencies, something that's native might not need any fertilizer at all. So identification is important for the start.

JULIE
Ideally, our palm fertilizer should be comprised of an 8 2 12 plus 4 magnesium or an 8 0 12 plus magnesium. And so again that 8 2 12 or that 8 0 12 represent the nitrogen, phosphorus and potassium. And of course we need that magnesium as well in our palm fertilizer. And so it's recommended to use a fertilizer that has nitrogen, potassium and magnesium in a slow release form.

And many of the micronutrients that are included in that palm fertilizer should actually be in a water soluble form.

ANNE
So you may be wondering why those middle numbers are zeroed out in the recommendations that Julie made for palm fertilizers. And that's because much of the native soil in central Florida is abundant in phosphorus, so it doesn't need to be applied. So 8 0 12 would be appropriate when applying it and not needing that phosphorus. So when we apply nutrients that can't be taken up they become pollutants.  So that would have a negative impact on our environment, particularly our water resources.

JULIE
And be sure to know your local fertilizer ordinance as well. And throughout Central Florida, different counties and cities have different restrictions. And if you live where there are restrictive periods, often called blackout periods, where nitrogen and phosphorus can not be applied, and these are often in the summertime, you may want to use a 0 0 12 plus 4 magnesium during that time, and the palm fertilizer should be applied at a rate of one and a half pounds per 1000ft².

Recently, I heard a great way to know what does that actually look like? You know, you might be saying, how do I calculate one and a half pounds per 1000ft²? And so Dr. Mica McMillan, a UF/IFAS researcher, said that it's about the size of a can of green beans. So simple enough.

ANNE
That's a great tip for applying fertilizer that can often be really confusing. Apply the fertilizer evenly under the canopy of the palm. Applying fertilizer in bands or spikes is not recommended because in these forms, the fertilizer’s concentrated. It might not burn the roots, so that that scattered application under the canopy is really important. And here in Central Florida, you can apply fertilizer three times a year from spring through fall.

And be sure to follow those local fertilizer ordinances that Julie mentioned. And a winter application isn't necessary as plant growth slows down and the nutrients are not needed at that time.

JULIE
Yeah. Another thing and don't prune off those yellow fronds. We cannot stress this enough. And so many people view these leaves and fronds and they, you know, seem very unsightly and so they just want to prune them. But by doing that you're actually just continuing the cycle instead of correcting the deficiency. This can also make determining the true problem difficult and can ultimately lead to the decline and death of the palm.

Because if you are constantly pruning off the symptoms and we don't truly know, those symptoms are just moving throughout the palm ultimately until they can't support anymore because of those nutrient deficiencies.

ANNE
Yeah and I think the takeaway is to remember that it takes a long time to correct these deficiencies. And those corrections are only going to be seen on that new growth. And so you'll have to kind of live with the damage that you see on those older leaves or fronds. 

So palms are very iconic in Florida. You see them everywhere you go. Look around your neighborhood and community as you walk or drive. You see them everywhere and lots of different types of palms also. And so for this episode's garden checklist, maybe in your own yard if you grow palms, try to identify the nutrient deficiencies that you see using the resources from this episode, and take the steps to make those corrections.

You might even start to recognize those nutrient deficiencies on neighbors or neighborhood palms as well. Learning to recognize the symptoms can help you determine the cause of deficiencies in your palms, and UF/IFAS extension offices can help you if you need assistance in that identification. Always remember that the right type of fertilizer is important for plant health, particularly in palms.

And it is important to know your local fertilizer ordinance, particularly if your palms are showing signs of lacking nutrients and use that recommended palm fertilizer. The 8 0 12 plus the 4 magnesium.

JULIE
For more information on keeping your palms healthy, information and workshops available, contact your local UF/IFAS Extension office. All resources for this episode are listed in the show notes.
 
JULIE
Thanks for listening to Your Central Florida Yard. We hope this episode has provided you with valuable insights and tips for your gardening journey in this unique part of the state. Your Central Florida Yard is produced by Anne Yasalonis and Julie Schelb. If you have any questions or suggestions for future episodes, find our contact information in the show notes.

This podcast is brought to you by the University of Florida's Institute of Food and Agricultural Sciences Extension, an equal opportunity institution. Thank you for listening and as always, happy gardening.

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Transcribed by L. Hice & J. Bayer-Fermier - 08/06/24

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