Why does tap water induce crown rot?

[Mauna Kea Cloudforest]

This Summer, I had at least a half a dozen palms contract bud/crown rot thanks to getting water into the crown. This happened either via overhead watering and/or sprinkler system water. However, these same palms do NOT get bud/crown rot from rain water. I know a small minority thinks this is a myth, but this phenomena is well documented, and is not confined to just California. Others in Florida have reported the same issue, so temperature is not necessarily a factor. For me. crown rot was most prevalent during the hottest most humid part of the Summer, which happened to be when I did most of the "face washing" for my palms.

On Dave's Garden, Geoff Stein writes: (http://davesgarden.com/guides/articles/view/1376/)

Another advantage of watering with a hose is I can spray each palm's foliage in an individualized fashion. Pauleen Sullivan also said that palms like to have their faces washed... in other words, they appreciate their foliage wetted frequently (most palms live naturally where rainfall far exceeds what we get here and appreciate any humidity they can get). There are some limits to ‘face washing', though, and this is particularly important to know if one waters palms with a hose, or especially with a broadcast sprinkler system (see discussion below). Some palms do NOT like to have their crowns repeatedly soaked with tap water, particularly during the cooler times of day or year. One of the most common reasons for bud rot (the bud is the growing center of the palm where the new leaves come from) in palms is excessive watering of the crowns. Palms that are exceptionally predisposed to this problem include most of the pinnate-leaved palms that do not have crownshafts. Why these palms as a group are particularly sensitive to this crown watering is unknown to me... and the ‘fact' of this is not really a ‘fact', but more of a personal observation. Some fan palms are also predisposed to this bud rot from overwatering their crowns, particularly the blue fan palms (blue Braheas, Chamaerops ‘cerifera', some blue Livistonas etc.). This is a lesson I have ‘learned' over and over and over again (obviously I am a slow learner) and my hopes are that you will pay particular attention to this warning so you do not have to learn from your mistakes as often as I have had to. Curiously these palms do not appear to be the least affected adversely by rainwater. There is obviously something about tap water (chemicals, lack of oxygen, lack of acidity, etc.) that is hard on these palm's crowns.

Obviously Geoff had enough of an issue that he wrote about it for the entire world to see. The crownshaft versus non-crownshaft observation is interesting, but I don't find it to be true. I had a small archont. maxima develop crown rot. After this Summer, I am going to stick stricktly with drip and be very careful when providing supplemental water. The hose will go directly on the soil.

For me, the remedy has been lime sulfur, a strong broad spectrum fungicide and bactericide that seems to work like a charm. I saved several palms from the brink of destruction with this stuff. I just let the lime sulfur dribble down the spear.

I am really puzzled as to why this is happening. Two micro-orgamisms known to cause this issue are Phytophthora palmivora and Thielaviopsis paradoxa, see http://edis.ifas.ufl.edu/pp144. But why would tap water favor these? pH? Do the spores thrive in underground PVC pipes?

[Phoenikakias]

Maybe the water poured with the hose or via a sprinkler in to the crown is much more than rain water falling directly from the sky. In my cold frame I water during warm season with sprinklers every day but only for 10 min. each time. Never, never, never faced any problems with crownrot. Of course relative humidity in there is only 50 to 60 (max)%. Another explanation can be that rain water is full of oxygen, which is not to the favor of fungi. Aeration and sun exposure as well may be crucial for the toleration limit of palms. I suppose that palms under canopy are less tolerant.

[JEFF IN MODESTO]

I've lost several pineapple plants this summer to this same type of thing.

Using an over head sprinkler.

All of my palms are watered low so the crown isnt being hammered by my 8.2 ph irrigation water. So no problem there.

Donno what the issue is.

[Phoenikakias]

I insist on water quantity plus the other mentioned factors in combination in my previous posting. Two examples . My two Medemia (yes the desert palm Medemia argun), have been watered through sprinklers for almost a decade in the cold frame and still never a crown rot symptom. Second example is a recently (last fall) acquired Phoenix rupicola (a pinnate palm without crownshaft). Sprinkler is stuck in to the palm's pot (so you can fancy how much water is accumulated near growing point). Still no crown rot! In fact the rupicola thrives! (photo below). I guess one has to keep a balance between climate and water quantity, it is another story however, whether this balanced watering time suffices also for the moistening of the soil, which in turn is also variable, and then problems begin!

[Jim in Los Altos]

Rain water is typically more acid than tap water, is oxygenated, and also picks up nitrogen atoms in the atmosphere on its way down. How those factors are relevant to preventing crown rot isn't clear to me but I've never had a problem with my tap water. I "face wash" most of my Pam's on a regular basis and most of the younger ones are subjected to overhead watering thee time a week as well. There apparently are some major differences in different municipalities water constitution.

[Matt in SD]

Has anyone considered that "tap water" might include microbes/pathogens that are present in the hose, or watering end that you use for watering? It's easy to imagine pathogens getting into the hose since it's very common to unscrew the hose from the tap, at which point the water flows back from the end, which often contacts the soil. It's also possible that some plant pathogens are not adequately killed by the methods used to process tap water...they certainly aren't tested for or regulated, and tap water is not exactly sterile.

It's very common when data/results seem to defy "logic" that the complexity of the system is just not being fully considered. This is often the case when people debate the safety of proven "safe" products (i.e. heavily studied things like drugs, pesticides, herbicides etc...). Often it is ingredients or contaminants other than the active ingredient that are responsible for the observed issues. Or it is the result of additional mitigating factors that were not present in controlled studies. Things tend to be more complicated than we imagine.

This debate has centered around fundamental differences between tap vs. rain water (dissolved gas content, hardness) but there are lots of differences between rain and watering a plant with tap water including how they are delivered to the plant, microbe content and probably other things I haven't thought of. Then you add in differences in local pathogen levels, other cultural practices etc... Given the fact that some people use overhead watering all the time with no problems, and some people have had catastrophic losses that seemed to result from overhead watering (I include myself in this latter group), it's probably not as simple as a fundamental difference between tap and rain water.

Matt

[Mauna Kea Cloudforest]

Has anyone considered that "tap water" might include microbes/pathogens that are present in the hose, or watering end that you use for watering? It's easy to imagine pathogens getting into the hose since it's very common to unscrew the hose from the tap, at which point the water flows back from the end, which often contacts the soil. It's also possible that some plant pathogens are not adequately killed by the methods used to process tap water...they certainly aren't tested for or regulated, and tap water is not exactly sterile.

It's very common when data/results seem to defy "logic" that the complexity of the system is just not being fully considered. This is often the case when people debate the safety of proven "safe" products (i.e. heavily studied things like drugs, pesticides, herbicides etc...). Often it is ingredients or contaminants other than the active ingredient that are responsible for the observed issues. Or it is the result of additional mitigating factors that were not present in controlled studies. Things tend to be more complicated than we imagine.

This debate has centered around fundamental differences between tap vs. rain water (dissolved gas content, hardness) but there are lots of differences between rain and watering a plant with tap water including how they are delivered to the plant, microbe content and probably other things I haven't thought of. Then you add in differences in local pathogen levels, other cultural practices etc... Given the fact that some people use overhead watering all the time with no problems, and some people have had catastrophic losses that seemed to result from overhead watering (I include myself in this latter group), it's probably not as simple as a fundamental difference between tap and rain water.

Matt

I agree, it's a complex system with a ton of variables. I know I don't get crown rot from rain water, only from my tap water, so obviously there's something in my tap water that causes the issue. That "something" might come from my irrigation system, which has been plagued by broken pipes, and I would not be surprised if there are rocks or dirt left in some of the pipes. In fact, I recently replaced the sprinkler that caused all the overhead problems, and it was full of small rocks. I am pretty sure that hoses and PVC pipes are haven for phytophtera to flurish.

[_Keith]

Maybe it's the fluoride, chloride, chlorinates, nitrates, nitrites, and whatever else they put in there that kills things like aquarium fish.

And don't forget those secret government experiments, too. Zombie Palm Apocalypse Coming.

[Gtlevine]

Well, just taking a stab at this out of the blue. Maybe the chlorine in the tap water kills beneficials in the crown enabling the spread of disease? I know all plants and animals live with billions of micro-organisms on the skin or leaves in symbiosis, so this is a guess. I know this is true for watering with chlorinated water also.

[Dypsisdean]

Two points:

1) The major difference between tap and rain water is TDS - total disssolved solids. You can see it on your leaves, in your shower, and especially in your swimming pool as your water gets old. As the tap water evaporates, it leaves those "white" deposits behind. These are "salts" of calcium, sodium, and all sorts of stuff depending on the source of the water. As the water evaporates from a swimming pool these minerals stay behind and build up, and you just add more every time you add water - until eventually it ends up ruining your tile, equipment, and plaster because the concentration gets so high. That is why you should periodically drain and refill your pool.

The crowns of palms are similar. As the water evaporates from the places that collect water, the minerals, are left behind, and this repeatedly builds up. The larger the little "pools" in the crownshaft, the more minerals are left behind after each filling. How this might contribute to crown rot, I don't know. But this is the main and consistent difference between tap and rain water. The solution is counter to what you may think, and that would be to actually forcefully spray water in the crown to dissolve and purge these deposits and other debris that could keep it moist down in there.

2) But having said that. Any time you are going to get water in the crown, whether irrigating, spraying chemicals, or "face washing" it should always be done as early in the morning as possible, when its going to be a sunny day, and when the humidity is at its lowest. It is much more important to follow this protocol in the cooler wetter months. That way you have the whole day for things to dry out. I watered exclusively with overhead sprinklers in SoCal. And I always had them come on right before sunrise - to assure a full day of drying the crowns, with the least amount of "wet time." I never had much of a problem.

[trioderob]

I think that high levels of N promote crown rot.

not that N is bad but plants that are in a high N environment will crown rot much worse and faster..........

so maybe it is that at the time of year where people are throwing ferts out (summer) N is high

in winter when folks are not throwing fert out (winter) is also when it happens to be raining

maybe something along these lines:

http://www.plantmanagementnetwork.org/pub/php/research/2009/strawberry/

Edited October 10, 2013 by trioderob

[LJG]

Dean, palms grow pretty fast so accumulation really wouldn't be an issue in my opinion.

I have used spray heads in my yard since the beginning. Tons of overhead watering and never an issue. This includes Fertigation. Ironically enough the three palms I lost this year were all tall and out of the way of their crowns being sprayed.

[edric]

The way I understood it, was the minerals ( dissolved solids) on the plant surface, give the fungi something to attach to, hence promoting there growth (the fungi), Ed

[sonoranfans]

Two points:

1) The major difference between tap and rain water is TDS - total disssolved solids. You can see it on your leaves, in your shower, and especially in your swimming pool as your water gets old. As the tap water evaporates, it leaves those "white" deposits behind. These are "salts" of calcium, sodium, and all sorts of stuff depending on the source of the water. As the water evaporates from a swimming pool these minerals stay behind and build up, and you just add more every time you add water - until eventually it ends up ruining your tile, equipment, and plaster because the concentration gets so high. That is why you should periodically drain and refill your pool.

The crowns of palms are similar. As the water evaporates from the places that collect water, the minerals, are left behind, and this repeatedly builds up. The larger the little "pools" in the crownshaft, the more minerals are left behind after each filling. How this might contribute to crown rot, I don't know. But this is the main and consistent difference between tap and rain water. The solution is counter to what you may think, and that would be to actually forcefully spray water in the crown to dissolve and purge these deposits and other debris that could keep it moist down in there.

2) But having said that. Any time you are going to get water in the crown, whether irrigating, spraying chemicals, or "face washing" it should always be done as early in the morning as possible, when its going to be a sunny day, and when the humidity is at its lowest. It is much more important to follow this protocol in the cooler wetter months. That way you have the whole day for things to dry out. I watered exclusively with overhead sprinklers in SoCal. And I always had them come on right before sunrise - to assure a full day of drying the crowns, with the least amount of "wet time." I never had much of a problem.

These are good points about the accumulation of hardness, Ca, Mg, Na etc. One effect could be that the high levels of these alkalai metals on the leaf surface will draw water from the leaf by osmotic forces due to the chemical potential gradient. This localized dehydration could effect the biological function of the sap, including the immune response. A weakened plant would be vulnerable to infection. I hadn't thought of this before, but it seems plausible... Also the accumulation of salts would be greater if you overhead water in the heat of the day when evaporation is highest, maximizing salt deposits.

Edited October 10, 2013 by sonoranfans

[pogobob]

I'm starting to think I suffer from crown rot

[_Keith]

I'm starting to think I suffer from crown rot

In that case, I think Penicillin will fix you right up.

[Dypsisdean]

Dean, palms grow pretty fast so accumulation really wouldn't be an issue in my opinion.

For fast palms in fast areas - perhaps so. But when you have palms in areas like Axel's, and people are claiming only 2 fronds a year as fast for some palms - how long do you think one of those water collecting crevices stay there? Take a shot glass and fill it up 1/2 inch and let it evaporate. Do that once a week for 3 or 4 months and see what you are left with. It might surprise you.

But again, it is highly variable as to what water district you are in, so anecdotal evidence will not be consistent. Since I was in the pool business, I would regularly check TDS in the fill water for new pools, all over No. County. And it varied considerably between districts and time of year as well - by a factor as much as ten times - as water is taken from different sources during the year, depending on the district's storage, wells, pipelines, and weather conditions.

[Mauna Kea Cloudforest]

Dean, palms grow pretty fast so accumulation really wouldn't be an issue in my opinion.

For fast palms in fast areas - perhaps so. But when you have palms in areas like Axel's, and people are claiming only 2 fronds a year as fast for some palms - how long do you think one of those water collecting crevices stay there? Take a shot glass and fill it up 1/2 inch and let it evaporate. Do that once a week for 3 or 4 months and see what you are left with. It might surprise you.

But again, it is highly variable as to what water district you are in, so anecdotal evidence will not be consistent. Since I was in the pool business, I would regularly check TDS in the fill water for new pools, all over No. County. And it varied considerably between districts and time of year as well - by a factor as much as ten times - as water is taken from different sources during the year, depending on the district's storage, wells, pipelines, and weather conditions.

Dean, there's no way water just sits there in the crowns, otherwise palms would be croaking all over the place from bud rot. Palms absorb that water, it doesn't just stay in place. Much of the minerals and other dissolved solids may just absorb as well. if there are pathogens present, they'll continue to live on in the tissue and cause bud rot.

About 80% of the palms I grow are ideally adapted to the climate here - ceroxylon, hedycepe, kentia, rhopies - and they all grow like weeds, if any rot shows up these things grow out of them really fast. Even on slow palms like sabals it's not an issue. It's only a problem on marginal palms, in which case it doesn't matter anyway since there's no point on keeping those alive. The bud rot on the one parajubaea cocoides in deep shade was pushed out quickly as it grew 12 inches of petiole/frond length in two weeks. I may talk a lot about the marginal stuff, it's because it's the fun experimental stuff.

[Dypsisdean]

Axel,

You missed my point. I was saying that in California any water that gets in the crown "crevices" evaporates in a day, leaving behind the minerals - not that water "sits there." And after this process is repeated a dozen or more times, like in the shot glass example, there may be substantial residue left behind. That is not the case with rainwater.

I don't think palms are absorbing that water as much as it is evaporating. In Hawaii, especially where I am, water evaporates at a snail's pace. It will just sit in those crevices for many days after a rain, and it isn't being absorbed by the palm.

I am only submitting an hypothesis. Due to my background, what I have explained is IMO the biggest single difference between tap and rainwater, and why plants grown with RO water are so much nicer looking.

[LJG]

Dean, the minute more water is added (from sprinklers or rain), it will fill those crevices and flush it out. Your shot glass example is a control where you are only filling back up and not overflowing for example. Of course dissolved salts (salinity) in soil must also be monitored to guarantee healthy plants. Hence why RO water is so great.

With that being said I can tell you my plants are super green right now after the first rain in 6 months. Amazing what rain water does to plants verses city water. The .6 inches I got flushed a lot of the build up in my soils and the winter rains will do the rest.

[Hammer]

Dean, the minute more water is added (from sprinklers or rain), it will fill those crevices and flush it out. Your shot glass example is a control where you are only filling back up and not overflowing for example. Of course dissolved salts (salinity) in soil must also be monitored to guarantee healthy plants. Hence why RO water is so great.

With that being said I can tell you my plants are super green right now after the first rain in 6 months. Amazing what rain water does to plants verses city water. The .6 inches I got flushed a lot of the build up in my soils and the winter rains will do the rest.

Len, most of the TDS get rinsed but not all. Over time, they will build up. Especially true in the summer. I have a palm that received overhead water before I bought it. The spots on the leaflets still have not washed away. Months later.

I have kept aquariums for nearly two decades and I can assure you that after a certain point nothing short of serious scrubbing will make a dent in some build up. Rinsing just doesn't cut it...and that's with fresh water not salt water.

CA summers are perfect to building up TDS deposits in plants. RO or rain are the only way around this.

Still doesn't answer the question re. whether or not TDS contributes to crown rot.

[sonoranfans]

Axel,

You missed my point. I was saying that in California any water that gets in the crown "crevices" evaporates in a day, leaving behind the minerals - not that water "sits there." And after this process is repeated a dozen or more times, like in the shot glass example, there may be substantial residue left behind. That is not the case with rainwater.

I don't think palms are absorbing that water as much as it is evaporating. In Hawaii, especially where I am, water evaporates at a snail's pace. It will just sit in those crevices for many days after a rain, and it isn't being absorbed by the palm.

I am only submitting an hypothesis. Due to my background, what I have explained is IMO the biggest single difference between tap and rainwater, and why plants grown with RO water are so much nicer looking.

I have to agree with dean, especially for hard water or high sodium. The problem with flushing it out of the crown with tap water is you will need velocity to mechanically dislodge the salts as they wont dissolve. Hard water is not good for dissolving these deposits by its definition. In florida this doesn't matter with the low evaporation rates, and if your water is not heavy in tds it may not matter either in California. But do any of you know if you have water high in hardness or tds? One rule may not satisfy all water conditions.

[LJG]

Dean, the minute more water is added (from sprinklers or rain), it will fill those crevices and flush it out. Your shot glass example is a control where you are only filling back up and not overflowing for example. Of course dissolved salts (salinity) in soil must also be monitored to guarantee healthy plants. Hence why RO water is so great.

With that being said I can tell you my plants are super green right now after the first rain in 6 months. Amazing what rain water does to plants verses city water. The .6 inches I got flushed a lot of the build up in my soils and the winter rains will do the rest.

Len, most of the TDS get rinsed but not all. Over time, they will build up. Especially true in the summer. I have a palm that received overhead water before I bought it. The spots on the leaflets still have not washed away. Months later.

I have kept aquariums for nearly two decades and I can assure you that after a certain point nothing short of serious scrubbing will make a dent in some build up. Rinsing just doesn't cut it...and that's with fresh water not salt water.

CA summers are perfect to building up TDS deposits in plants. RO or rain are the only way around this.

Still doesn't answer the question re. whether or not TDS contributes to crown rot.

I doubt that is hard water build up on your leaves but most likely daconil or some other prior treatment. I have thousands of plants getting city water and none have spotting from hard water - and my water is hard too. If what you were saying were true all our gardens running popups would have spotting on plants.

I am not saying you are wrong by the way. If indeed you are seeing build up on leaves that is a new one to me. I just don't see it here.

[sarasota alex]

A couple of observations that I've made over the last few years:

- Water I use to water my plants with is usually much colder than our naturally warm Florida rain. Sometimes possibly 20-30 degrees F colder than what a plant expects. Not sure about California though. Maybe that has something to do with it.

- Last couple of summers a few of my palms rotted due to excessive natural rainfall. So it's not just the tap water.

[Kris]

hi,

Even I have lost few palms this way.but my potted palms love over head shower.But my palms growing in the ground show signs of fungus attach if I spray the leaves with a hose pipe feed by well water.

solution : I stopped this practice and my palms are very happy now.

I just water the roots.evrn if there is dust in the palm leaves I never use water to clean it.