Whenever I read "grows in calcareous soils" I know that species can at least tolerate high pH soil. Whether or not it prefers it, I usually don't know.

I've been adding Dolomiite Lime to the following palms: Breahea armata, Brahea decumbens, Pseudophoenix spp.

Do these palms really require basic soil? Or do they prefer it, or thrive more in it than if your soil was neutral or acidic? What other palms do you add lime to?

I have a hair-brained theory that the powdery palms like B. armata and decumbens will produce more powder if given more lime. Probably just because it's white powder, no real evidence to support my theory.....just speculation I guess.

I also planted some B. decumbens with broken pieces of concrete in the bottom of the holes. Is that a thing? They are doing well, just not sure if it actually helps or what?

I'd really like to hear your thoughts on this subject.

I have very acid pine forest soils. Brahea armata seems to be growing well with strong color. It took a year and a half to fully get established, but its doing great.

I found this on brahea armata:

Requirements: Full sun. Excellent drainage.

Common names: Mexican Blue Palm; Blue Hesper Palm.

This is a beautiful, cold-tolerant palm with unusual blue-green fan-shaped leaves. Rather slow growing, this palm can take quite heavy frosts when mature. However, we recommend that it be given some protection when young. It doesn't care for too much winter wet and so it should ideally be grown in a spot sheltered from rain. When planting it, take care to ensure that the soil is freely drained. You may want to raise the level of the planting area above the level of the garden by mounding soil slightly. If you have heavy clay soil, you should dig in large quantities of organic material such as well-rotted farmyard manure, coir or peat mixed in with some sharp sand or grit. Brahea armata likes quite alkaline conditions and may grow faster if lime is added to the soil.

My experience is that armatas grow very well in alkaline soils. I grew them in alkaline soils in AZ, and they were a lot faster than most others reported. 10-12 new fronds a year was typical after the roots were established. they also like heat, no surprise there as they come from Baja California.

the white wax on armatas is not composed of calcium, but they may be happier and healthier in alkaline soils, hence more white. From what I have seen the wax on armatas decreases on existing fronds over winter and increases with new fronds in the heat. there is likely genetic variation, but sun and heat are also a factor if you consider the function of the wax. the white wax reflects sun and limits leaflet heating and subsequent evapotranspiration of leaves. This is probably why palms like bismarckia, brahea armata, and chamaerops cerifera are so well adapted to the hotter desert areas.

I use dolomite lime on almost all palms, but in reality, my soil pH is so high that I probably don't actually need it. I use it mostly for the calcium/magnesium balance and the soil fungus inhibitory action. High pH is the one reason palms are the only thing that grow well on my hillside.

My impression as a whole is that the majority of palms seem to prefer alkaline soil. But even if a palm required more acidic soil, (I have yet to find which ones do) I would just combine the dolomite lime with camelia and rhododendron fertilizer. The dolomite lime has more of a buffer function than anything, it helps stabilize the pH, and it sure greens up palms well.

I grow a lot of citrus and avocado, and my citrus especially require a lot of acidifying amendment, but so do my avocados. Without it they won't grow here. But I've never ever run into a single palm that wouldn't grow on its own in my native soil. I've never had to amend with acidifying fertilizer. I've got mostly sandstone with some limestone.

My palm growing secret consists of a combo dolomite lime, urine and vigoro palm stakes. So far, I'm getting impressive results with just that.

I will have to concur with Tom's assessment on brahea armatas, but only the ones grown in part shade. My full sun grown armatas stay silver white through the Winter, and I can't imagine an armata in Arizona in full sun going green in the Winter sun there. The ones that get only a few hours of sun per day in the Summer green up in the Winter to a navy blue-green, and silver up in the Summer.

I doubt there's a correlation with silver production and pH, but I am certain the dolomite lime takes care of the frequent K-deficiencies that many brahea armatas and claras suffer from.

Hmm.

For what it's worth, I've found that palms, as a group aren't that fussy about PH.

Since we have water that's high in mineral salts, PH tends to get above neutral into the alkaline range.

That said, I'm curious to see what Matt's results are. Might be fun to experiment (muah ha ha ha!) on plants in pots.

I use dolomite lime on almost all palms, but in reality, my soil pH is so high that I probably don't actually need it. I use it mostly for the calcium/magnesium balance and the soil fungus inhibitory action. High pH is the one reason palms are the only thing that grow well on my hillside.

My impression as a whole is that the majority of palms seem to prefer alkaline soil. But even if a palm required more acidic soil, (I have yet to find which ones do) I would just combine the dolomite lime with camelia and rhododendron fertilizer. The dolomite lime has more of a buffer function than anything, it helps stabilize the pH, and it sure greens up palms well.

I grow a lot of citrus and avocado, and my citrus especially require a lot of acidifying amendment, but so do my avocados. Without it they won't grow here. But I've never ever run into a single palm that wouldn't grow on its own in my native soil. I've never had to amend with acidifying fertilizer. I've got mostly sandstone with some limestone.

My palm growing secret consists of a combo dolomite lime, urine and vigoro palm stakes. So far, I'm getting impressive results with just that.

I will have to concur with Tom's assessment on brahea armatas, but only the ones grown in part shade. My full sun grown armatas stay silver white through the Winter, and I can't imagine an armata in Arizona in full sun going green in the Winter sun there. The ones that get only a few hours of sun per day in the Summer green up in the Winter to a navy blue-green, and silver up in the Summer.

I doubt there's a correlation with silver production and dolomite lime, but I am certain the dolomite lime takes care of the frequent K-deficiencies that many brahea armatas and claras suffer from.

Do you cultivate this way also Butia eriospatha?

Thanks Buffy, that's interesting that they do well in your acidic soil. Good info.

Tom, your experience is valued as always. Thanks.

Axel, I have to admit that I'm a little miffed at your comments. As a whole, from what I've read and heard other growers say, is that palms generally prefer slightly acidic soil. The fact that you have basic soil and you're adding more lime seems very odd to me. And you say it greens them up? Very interesting. Do you mulch heavily?

I use a lot of Dollomitic Lime in my garden and have been pushing it for about two years now. While the benefits of changing pH are small in my opinion (for plants coming from a higher pH soil), it is the natural addition of Ca and Mg that is huge. Both these are key to plant metabolism/structure and found in very limited amounts (or sometimes none at all) in most fertilizers. I tend to think people confuse greening due to use with pH change but in fact it is the addition of Ca and Mg.

Hmmm, sounds like Len and Axel are seeing the same results. Very interesting. I would have never dared to add Dolomite Lime to something like my Carpoxylon or Pinangas.

?....but I am certain the dolomite lime takes care of the frequent K-deficiencies that many brahea armatas and claras suffer from.

How does Dolomitic Lime cure Potasium deficiencies?

?....but I am certain the dolomite lime takes care of the frequent K-deficiencies that many brahea armatas and claras suffer from.

How does Dolomitic Lime cure Potasium deficiencies?

Yes! I have also the same question, since potasium and magnesium compete with each other, as far as I know. That's why in the known 3-1-3 formula is added also 1 portion mg.

Thanks Buffy, that's interesting that they do well in your acidic soil. Good info.

Tom, your experience is valued as always. Thanks.

Axel, I have to admit that I'm a little miffed at your comments. As a whole, from what I've read and heard other growers say, is that palms generally prefer slightly acidic soil. The fact that you have basic soil and you're adding more lime seems very odd to me. And you say it greens them up? Very interesting. Do you mulch heavily?

I add dolomite lime for the same reason Len does - to handle the K and Mg balance and add Ca. My soil is highly deficient in Ca. As I said previously, dolomite lime is more of a buffer, Calcium Magnesium Carbonate does more to stabilize pH than it does to change it. The definition in chemistry is this: "A buffer is a solution containing either a weak acid and its salt or a weak base and its salt, which is resistant to changes in pH."

The general assumption people make is that rainforest and emergent canopy primary forest palms are acid loving because they naturally grow in forest humus, and that secondary forest colonizers and desert and open savana palms are alkaline loving because they naturally grow in arid soil that will be naturally more alkaline due to the lack of rainfall. However, I have made the same observation that Dave has made: I find that palms just aren't fussy about pH. I grow a lot of acid loving plants such as citrus and some rhododendrons. Acid loving plants will NOT grow in my soil without adding acidifiers. However, I have yet to find a single palm that doesn't grow in my soil without acidifiers.

My conclusion is that messing with pH is probably a waste of money and effort. Better spend the time adding macro and micro nutrients - hence the dolomite lime. I do believe dolomite lime helps in the uptake of K. I've seen Len's palms, they're some of the greenest healthiest palms I have seen in San Diego County so far.

However, now that I increased the list of species that I grow, I may start to play with adding rhododendron acidifying fertilizer to some of those rainforest canopy palms and see if I get faster growth.

Konstantinos, butia grows in my soil without the addition of anything. It needs no fertilizer and no additive of any sorts. Butias would be weeds if we had Summer rainfall.

Thanks Buffy, that's interesting that they do well in your acidic soil. Good info.

Tom, your experience is valued as always. Thanks.

Axel, I have to admit that I'm a little miffed at your comments. As a whole, from what I've read and heard other growers say, is that palms generally prefer slightly acidic soil. The fact that you have basic soil and you're adding more lime seems very odd to me. And you say it greens them up? Very interesting. Do you mulch heavily?

With a few exceptions the palms I have am growing also seem to prefer neutral or slightly acidic soil. Copernicias and braheas do seem to like alkaline soil. High pH in soils makes some micros like Mg, Fe and Mn less accessible to the plant as these tend to form insoluble hydroxides. I remember reading that some palms can access these minerals better than others as hydroxides, and we also know that some palms are more nutrient dependent than others. I would put brahea armata/clara and bismarckias in the latter group, that is, they are not heavy micronutrient feeders. Dolomite would be a good way to ensure Mg/Ca for palms that tolerate alkalinity. I don't see K as being supplied by a dolomite application, rather you may need more K if you use dolomite(CaCO3,MgCO3) because K and Mg can limit each others uptake when one is in considerable excess(see below under "cation balance" and "interactions").

Factors Affecting K Availability

Soil CEC: Plant-available soil K is in the ionic (electrically charged) form. This charge is positive, making K a cation, represented as K+. Cations are attracted to, and held by negatively charged colloids (primarily clay and organic matter) that make up the cation exchange capacity (CEC) of the soil. The larger the CEC, the more K that can be held by the soil and the higher the soil test needed to adequately feed plants.

Soil test K:Higher soil test K increases the available K, by increasing the amount and balance of K relative to other cations.

Cation Balance: Where there is a significant imbalance between available K and the other major cations (Primarily Calcium, Magnesium, and sometimes Hydrogen, Aluminum, or Sodium), it may affect the availability of K to the crop.

Soil Moisture: K is transported within the soil and is absorbed by plant roots in the soil water. Therefore a water deficiency results in less K absorption.

Soil pH: As the soil pH is reduced (increasing soil acidity) the availability of K is often reduced.

Soil Temperature: Cold soils often reduce the availability of K.

Soil compaction: Compacted soils often reduce the availability of K.

Soil Drainage/Aeration: As soil drainage is improved, K uptake typically improves.

Soil Salinity: Saline soils often have excess sodium (Na). One of the negative effects of excess Na is that it reduces the availability of K.

Interactions

K/Mg ratio: Each of K or Mg can reduce the uptake of the other when the "normal" soil balance does not exist. Typically, we find high K levels inhibiting the uptake of Mg. However, some Midwest soils have enough Mg to reduce K availability, especially to high-demand crops.

Other Cation ratios: There are occasions when K uptake might be restricted due to an imbalance with other cation elements in the soil. For example, in many high pH soils there is an excess of Ca. Competition from this Ca could reduce uptake of K. Strongly acid soils will often have an excess of hydrogen (H), aluminum (Al), iron (Fe), and possibly other cation elements. These excess elements can compete with K for entry into the plant, and/or set up soil conditions that are unfavorable to efficient K utilization.

Soil pH: This subject is intertwined with both of the previous points. While we don't think of K as leachable, in acid soils with low CEC's, we find that K can be leached somewhat. Where initial soil tests or fertilizer programs are not sufficient to offset this loss mechanism, we can see lower yields and crop quality.

Thanks everyone for all the great info. I'm learning a lot. Keep it going. This is a great discussion.

And Axel, I agree, Len's palms are superb, so I take his advice under strict counsel. I have no idea what I just said.

moderate alkalinity(pH~8) shouldn't be an issue for micronutrient availability. This is what I expect from liming...about pH=8(buffers at pH~8.3 in salt water.

google "micronutrient availability ph chart" and you will get some charts that show what the limitations are.

Tom, Gardening should be simple to understand, what you posted only a soil chemist could decipher.

Can you translate that into plain English?

Here's one of the charts I found. Again, dolomite lime isn't making the soil more alkaline, other mechanisms are at work in increasing K availability.

Matty - as to the Psuedophoenix, I don't think it matters about adding lime. As long as the soil is well drained. We saw vinefera and lediniana in the DR growing in nice soil. The exception may be the eckmanii. Those suckers were growing on pure limestone.

Farmer and vegetable gardeners here, on our heavy clay soils, lime there fields every couple of years, no matter what they are growing. I have never asked one of them why, but like all I too adhere to the practice. After reading this thread, I did some research and perhaps these articled will shed some light on the mechanical reason.

http://www.britishlime.org/technical/soil_stabilisation.php

http://www.finegardening.com/how-to/articles/improving-clay-soils.aspx

Tom, Gardening should be simple to understand, what you posted only a soil chemist could decipher.

Can you translate that into plain English?

When we talk of high pH, we are talking pH=9 and up. Under these conditions many palms will do very poorly as Fe, Mn,B, Cu Zn become unavailable partly due to being insoluble salts at that pH and partly due to microbial/metabolic reasons that I am less familiar with. Iron, in particular, starts really tailing off in availability at above pH 7.5. For this reason heavy iron feeders should be kept near neutral or slightly acidic pH. Micros that become unavailable at acid pH(<=6) are Ca Mg,P, and molybdenum(Mo). So a great range would be 6.5-7.5 for many palms. the exceptions are out there like armatas, copernicias, and bizzies and I'm sure several others. I know of no reason palms should like pH=6 or lower. If you lime, you are adding Mg,Ca as carbonates and they have a buffering effect below pH=9(8.3?), so soil pH isn't the issue with adding dolomite, excepting the heavy Fe feeders. However a large excess of Mg can lead to poor K uptake at an otherwise acceptable pH. Note that K uptake is very good at pH=8, but if you have to much Mg, you can get a potassium deficiency in palms that are heavy potassium feeders(Copernicia). Basically, the Mg will displace the K similarly to the way excess Ca displaces Mg. So when you repeatedly add dolomite to a low drainage soil there can be a risk of introducing K deficiency. It is also true that if you add too much potash, the K will limit Mg uptake and you could get a magnesium deficiency. I think its obvious that people who use lime and have very healthy gardens don't have excess Mg. Learning the deficiency signs allow you to identify the deficiency and then to find the cause. There are several good publications on the internet that will give you views of K, Mg deficiency.

In summary:

1) Soil pH 6.5-7.5 is probably ideal for most palms, but some are tolerant outside this range.

2) the soil you start with will determine how much lime you can use before you get K deficiency from inhibition by Mg. High Mg soils with low drainage will be an issue and you will need to be careful or risk suffering K deficiency. Also indiscriminate use of potash is a bad idea as too much K will cause Mg availability issues.

In your case Axel, you have high drainage soils so the risk in using lime and having too much Mg is low. So it makes sense that you have palms that are loving the lime applications.

All bets are off when adding lime to potted palms. I know for a fact it switches acidic potting soil to more neutral or basic. This has been one of a few game changers on my success in growing NewCals.

All bets are off when adding lime to potted palms. I know for a fact it switches acidic potting soil to more neutral or basic. This has been one of a few game changers on my success in growing NewCals.

At the risk of contradicting myself, I heard claims that NewCals prefer acidic soil, is that not the case?

All bets are off when adding lime to potted palms. I know for a fact it switches acidic potting soil to more neutral or basic. This has been one of a few game changers on my success in growing NewCals.

At the risk of contradicting myself, I heard claims that NewCals prefer acidic soil, is that not the case?

Nope. Soils similar to Cuban.

All bets are off when adding lime to potted palms. I know for a fact it switches acidic potting soil to more neutral or basic. This has been one of a few game changers on my success in growing NewCals.

At the risk of contradicting myself, I heard claims that NewCals prefer acidic soil, is that not the case?

Nope. Soils similar to Cuban.

Len - Cuba has a range of soil types. Magote limestone cliffs, volcanic derived soils, sandy acidic soils, the swampy soil areas, and a few serpentine soil areas.

The palm will collect the dolomite lime improved soil if and when it requires it as I understand. Putting it around the palm tree is simply a safe way to ensure it meets it's needs if they are required, the soil might be good enough. There shouldn't be any harm in playing it safe. I stand/sit to be corrected.

Very interesting discussion...

a more simple discussion on soil pH and its effects

http://www.the-compost-gardener.com/soil-ph.html

The pH of the rainforest floor is 4.5-5.5. And since about 75% of all palm species grow in tropical rainforests, I think it's fair to say that most palms prefer pH to be between 4.5 and 5.5. And most of those palms are very sensitive to soil pH levels. In order to be able to grow rainforest species at the Fairchild Tropical Gardens they actually excavated and removed natural Miami area soil (which ranges from pH 7.4 to 8.4) and filled those areas with acidic soil.

Also cloud forest soil pH ranges from a toxic 3.0 to about 5.4.

All bets are off when adding lime to potted palms. I know for a fact it switches acidic potting soil to more neutral or basic. This has been one of a few game changers on my success in growing NewCals.

Len,

I always add some dolomite to my potting soil when I'm making a new batch, but generally I dont do it very scientifically...just chuck in a handful per wheelbarrow, or thereabouts.

My questions would be:

First, have you (or anyone else) come up with what you would consider a consistent and reliable ratio of dolomite per litre of potting mix (I guess this depends on other factors such as ammount of acidifiers like peat, pine bark, etc.).

Secondly, have you experimented with top dressing pottted palms with dolomite when you suspect that the ph is low in the pot or there is a Ca or Mg deficiency? If so, again is there a "safe" limit to apply?

Third, my garden soil is acidic free draining sand, so I've always assumed that I could apply dolomite till the cows come home (particularly as most of our rainfall occurs in winter, so leaching is always a factor). But I've also heard/read that its a good practice to alternate the use of Dolomite with non-dolomitic lime to avoid excessive build up of Mg in the soil. Does this make sense?

Cheers,

Jonathan

The pH of the rainforest floor is 4.5-5.5. And since about 75% of all palm species grow in tropical rainforests, I think it's fair to say that most palms prefer pH to be between 4.5 and 5.5. And most of those palms are very sensitive to soil pH levels. In order to be able to grow rainforest species at the Fairchild Tropical Gardens they actually excavated and removed natural Miami area soil (which ranges from pH 7.4 to 8.4) and filled those areas with acidic soil.

Also cloud forest soil pH ranges from a toxic 3.0 to about 5.4.

I can't grow that specific 75% anyway, I am more interested in the 25% that is subtropical.. It's also worth pointing out that A doesn't imply B, correlation doesn't imply causation. Just because a palm grows in pH of 5 doesn't mean it won't grow in a pH of 8. Fairchild wants to reproduce native conditions, that makes sense. But how many of those palms can actually handle higher pH? I bet many of them do just fine.

All bets are off when adding lime to potted palms. I know for a fact it switches acidic potting soil to more neutral or basic. This has been one of a few game changers on my success in growing NewCals.

At the risk of contradicting myself, I heard claims that NewCals prefer acidic soil, is that not the case?

Nope. Soils similar to Cuban.

Len - Cuba has a range of soil types. Magote limestone cliffs, volcanic derived soils, sandy acidic soils, the swampy soil areas, and a few serpentine soil areas.

Understood, but it is safe to say most palms in New Caldonia and Cuba/Hispaniola grow in more Alkaliane soils. The most fertile soils in Cuba are the red limestone soils.

Len, what are some of the palm families that might life alkaline soils?

All bets are off when adding lime to potted palms. I know for a fact it switches acidic potting soil to more neutral or basic. This has been one of a few game changers on my success in growing NewCals.

Len,

I always add some dolomite to my potting soil when I'm making a new batch, but generally I dont do it very scientifically...just chuck in a handful per wheelbarrow, or thereabouts.

My questions would be:

First, have you (or anyone else) come up with what you would consider a consistent and reliable ratio of dolomite per litre of potting mix (I guess this depends on other factors such as ammount of acidifiers like peat, pine bark, etc.).

Secondly, have you experimented with top dressing pottted palms with dolomite when you suspect that the ph is low in the pot or there is a Ca or Mg deficiency? If so, again is there a "safe" limit to apply?

Third, my garden soil is acidic free draining sand, so I've always assumed that I could apply dolomite till the cows come home (particularly as most of our rainfall occurs in winter, so leaching is always a factor). But I've also heard/read that its a good practice to alternate the use of Dolomite with non-dolomitic lime to avoid excessive build up of Mg in the soil. Does this make sense?

Cheers,

Jonathan

1) Nope. I do what you do and just throw a few hand full's out there. I use granular. For my potting soil I use 4 cups lime and mix it with my potting soil which amounts to 3 cubic feet per 'batch' I make. Do you have a soil pH meter? These are great but I doubt very accurate, but it at least gives you a rough idea where you stand.

2) I use to top dress and never had any issues other than it would cake sometimes. Now mix it into my soil for my potted NewCals.

3) I have no clue. Many palms from NewCal grow in rich soils loaded with Magnesium. These are the only plants I use Dolomite on every year. Others I spot treat. Pete in Australia turned me on to do this with Licualas and so touchy heeled Dypsis. It has really made a difference for me.

I would assume a granular would work better then micronized for you?

Len, what are some of the palm families that might life alkaline soils?

Keith, I would assume any plant that grows in a limestone environment. Palms from parts of NewCal, parts of Cuba/Hispaniola and parts of Papua New Guinea for example.

Len, what are some of the palm families that might life alkaline soils?

Keith, I would assume any plant that grows in a limestone environment. Palms from parts of NewCal, parts of Cuba/Hispaniola and parts of Papua New Guinea for example.

I was just curious. In 9a I am limited to what I can grow, and like most folks when I get palms I just stick them in what I have, which is acid clay soil. Only on a few plants have I attempted any real ph modification, so I was just wondering if I might be missing the boat on some of them.

To be honest Matt,

I was a little "miffed" by your thread title...I saw the topic "liming" and I thought I was going to see a thread on a huge party that I was not invited to!

FINS TO LIMING!!

Whenever I read "grows in calcareous soils" I know that species can at least tolerate high pH soil. Whether or not it prefers it, I usually don't know.

I've been adding Dolomiite Lime to the following palms: Breahea armata, Brahea decumbens, Pseudophoenix spp.

Do these palms really require basic soil? Or do they prefer it, or thrive more in it than if your soil was neutral or acidic? What other palms do you add lime to?

I have a hair-brained theory that the powdery palms like B. armata and decumbens will produce more powder if given more lime. Probably just because it's white powder, no real evidence to support my theory.....just speculation I guess.

I also planted some B. decumbens with broken pieces of concrete in the bottom of the holes. Is that a thing? They are doing well, just not sure if it actually helps or what?

I'd really like to hear your thoughts on this subject.

Len, what are some of the palm families that might life alkaline soils?

Keith, I would assume any plant that grows in a limestone environment. Palms from parts of NewCal, parts of Cuba/Hispaniola and parts of Papua New Guinea for example.

I was just curious. In 9a I am limited to what I can grow, and like most folks when I get palms I just stick them in what I have, which is acid clay soil. Only on a few plants have I attempted any real ph modification, so I was just wondering if I might be missing the boat on some of them.

Keith, again I am not trying to alter the pH of my soils outside. I do it for the Ca and Mg. Considering limestone moves very slowly through soil, it would take forever to change pH unless tilled in.

Mikey (deceased forum member) years ago gave me a tip on limestone loving palms I was about to plant. He told me what he and some others that grew with him did when Limestone rocks were not available. They would be to buy bags of cement, wet it, let it harden then sledge hammer into smaller blocks and then plant the palms on top in the hole. My Cuban plants look very good for SoCal now. I had one that didn't as I think it was too cold sensitive so I ripped out. When digging out I noticed roots had started to encase the cement chunks.

Hey, I used mikey's cement technique and didn't even know it. Those B. decumbens planted with cement are doing very well. Actually the three decumbens not planted with cement are the only ones that haven't turned blue yet

Hey, I used mikey's cement technique and didn't even know it. Those B. decumbens planted with cement are doing very well. Actually the three decumbens not planted with cement are the only ones that haven't turned blue yet

I smell a bag of Quickcrete on the way.

On a related note, many tropical soils are lateritic, a process of weathering that takes place mostly between the tropic of cancer and the tropic of capricorn, see http://en.wikipedia.org/wiki/Laterite.

"Lateritic soils are the subsoils of the equatorial forests, of the savannas of the humid tropical regions, and of the Sahelian steppes. They cover most of the land area between the tropics of Cancer and Capricorn."

Laterite soil happens to be rich in minerals and happens to have a high pH and it sits just below the surface soil, which in a rainforest will usually be rich in humus and with a low pH. It would seem that most tropical rainforests are going to have palms that sit in acidic humus combined with the next layer being alkaline laterite. This means that most likely, palms will thrive with high mineral content that might drive up the pH combined with surface soil that is low in pH.

My conclusion: concrete chunks in the hole might not be a bad idea, better yet, mix in some lava rock and dolomite lime for good measure. Then make the top part of the soil rich in humus and organic matter that drives up acidity. Then you probably have the right cocktail for growing palms.

My second conclusion is that because of this combination, palm roots are very likely insensitive to soil pH, within reason, of course, the chart above seems to suggest that in between 5.5 and 8.5 there is still going to be plenty of nutrient uptake. Dave's observations and my observations are consistent and support the notion that palms are indeed not very fussy about pH.

Len, what are some of the palm families that might life alkaline soils?

Keith, I would assume any plant that grows in a limestone environment. Palms from parts of NewCal, parts of Cuba/Hispaniola and parts of Papua New Guinea for example.

I was just curious. In 9a I am limited to what I can grow, and like most folks when I get palms I just stick them in what I have, which is acid clay soil. Only on a few plants have I attempted any real ph modification, so I was just wondering if I might be missing the boat on some of them.

Keith, again I am not trying to alter the pH of my soils outside. I do it for the Ca and Mg. Considering limestone moves very slowly through soil, it would take forever to change pH unless tilled in.

Mikey (deceased forum member) years ago gave me a tip on limestone loving palms I was about to plant. He told me what he and some others that grew with him did when Limestone rocks were not available. They would be to buy bags of cement, wet it, let it harden then sledge hammer into smaller blocks and then plant the palms on top in the hole. My Cuban plants look very good for SoCal now. I had one that didn't as I think it was too cold sensitive so I ripped out. When digging out I noticed roots had started to encase the cement chunks.

WHOA

I have a use for that bag of cement I was about to toss . . . .