Learning to garden in this environment has been a steep curve, I am trying to regain my formerly green thumb. There are some things that have just been perplexing to me. One is that it is very difficult to grow mint. Mint! The stuff that eats your yard up north if you don’t pull out the runners and the stuff that I had growing without dirt in the waterfall of my pond up there. How could mint be hard to grow?
Well, it is. Most people I know have just given up and don’t try anymore. A local woman at a nursery told me that you have to keep it out of the rain if you want it to live. Then, someone else said the same thing. It stuck in my head because it seemed an odd requirement for a water loving plant. I’ve tried it in several different ways, in and out of the sun, in and out of pots. It grows for awhile and then it starts fading and turns brown and dies.
Something similar just happened to my gardenia as well. It looked good, was putting out new leaves, bloomed. Then a week or so ago it started turning brown and it quickly died. Death appeared to come from the ground, the top of the plant was the last to go.
What do these two have in common, that’s one of the things that has run through my mind. I googled ideal conditions for mint and discovered that it prefers a more acid soil. Gardenia’s need a very acidic soil to thrive and I had been using some acidic fertilizer and adding coffee grounds to the gardenia.
It occurred to me that the start of the rainy season might have something to do with this sudden death situation. I collected some rainwater and used my pond test kit to check the PH. Leapin’ Lizards! It was over 9 – extremely alkaline. I doubted the results and tried it with a new catch of rain water in a different clean plastic container – still over 9. How is this possible? I googled and I still don’t really know. What I found is that highly alkaline rain usually occurs near deserts and is due to alkaline dust being blown into the rain. I don’t think we really have that extreme a situation here in the Yucatan. Other than that, it just seems that it isn’t something that occurs often or no one writes about it.
So, now I’m wondering if the casual comment from a savvy Mexicana is a real clue, keep the mint out of the rain. The rain could be adding so much alkalinity to the plant that it just curls up and dies. If so, it’s near hopeless as it would be too difficult to keep any plant that needs full sun out of the rain. I’m not that kind of masochist that I would run a pot of mint in and out of the sun and water it only with RO – although… I might try it just as an experiment. Or, I’m off on a wild tangent.
There are other possible leads to follow.
- It could be that one of the dogs used that gardenia way too much as a fire hydrant. I’m less likely to believe that one since we have been getting so much rain and it has to be diluting any pee that ends up out there. The mint is in two places and the dogs aren’t able to pee on it. I am going to start adding tomato to the dog food to acidify their urine, it might help.
- It could be that the rock underneath that particular gardenia doesn’t drain fast enough and it drowned from wet roots. I pulled it up and there is a wet rotting mass of root under there. That would happen though if the roots were dying and no longer absorbing water in all this rain.
- Is it just this gardenia or are all gardenia’s hard to grow here? Others have told me that they have a hard time with them but I see huge trees in yards that look to me like gardenia. I need to investigate one of those more thoroughly.
- It could be one element is missing from the soil and it eventually kills the plant. Magnesium has been suggested. I found the close equivalent to epsom salt and I’ve put that on the sickly mint to see if it greens up and recovers. Some reading online though suggests that too much magnesium could cause high PH.
- The dead gardenia and the dying mint could be completely unrelated. It could be heat, humidity, iron deficiency, nematodes or other bugs in the soil, a myriad of other things.
I’m friggin lost. I did not do well in chemistry and that’s an understatement.
dying gardenia
Who would of thought that anything would not grow in the Yucatan??? Mint is like a weed and grows everywhere. However a funny thing is that we have had mind here in our bed for 5 years and none of it came back this year. That is correct. NONE!!! Granted we live in Colorado at 9100′ but this has not been a problem in the years past. Very strange… Have you tried lemon balm? I also would have thought no problem with gardenias. Go figure. Thanks for doing all of the testing for those that are coming after you have paved the gardening way. Can Theresa grow mint? I wish you good luck with your chemistry project.
I assumed that you had Googled everything related to this discussion in English so decided to go see what I could find out in Spanish. So far, everything I have read about the rain in the Yucatan indicates that it should fall in the range of pH 5-6 and nowhere near 9. In fact, the discussion is about the slightly acidic rain that dissolves the limestone and forms cenotes among other things.
What I did find, was an article about compost. The pH ranges between 7.6 – 9.9 with the latter pH related to compost from gardens and parks. The lower pH came from compost at municipal dumps.
So, I still have not solved your mystery, but maybe the soil you just brought in came from composted soil and has a very high pH.
I would catch some rain water and test its PH. In the city the vaporized air could be affected by any number of things spewed in the air. Also you might try getting some good medio PH soil and doing a planter growth test in doors.
You are one I expect that can get to the bottom of just about anything. I look forward to your discovered solution.
By the way – Anita grows mint at our Casita with excellent success and somewhat milder success at our Rancho. Haven’t done the PH thing.
Jonna,
The pH of rain water is only acidic if it contains only water and dissolved CO2.
Initial rain falls of Northern Yucatan rain water contains lots of dust, algae, etc.
(Notice how much algae and crud is injected by rain water into local swimming pools: because the dust & algae chew up the pool’s chlorine, and then cause the pools to turn into algae gardens, unless the pool is treated with Copper or some other algaecide.)
Northern Yucatan’s dust is both alkaline and corrosive. The dust here has lots of calcium carbonate from all the exposed and nearly exposed limestone. The dust along the northern coast also has noticeable amounts of “special dust” that comes from the bursting bubbles in the Gulf from wave action: salt, protein-acious gunk, and NaOH & Ca(OH)2 (sodium hydroxide and calcium hydroxide) that turn into dust particles from the fine aerosol seawater droplets that come from splashing and crashing waves.
If you set out a flat piece of normal (non-galvanized/non-treated) steel here, the top surface that’s exposed to Northern Yucatan dust oxidizes or rusts, while the underside remains fine. If you put the same steel into an open mouthed plastic bag, where water vapor and humidity move in and out, but restricts the access of falling dust, the steel stays fine and unoxidized.
Ever noticed how the terminals on AA and AAA batteries oxidize here, and how electronics like computer cables oxidize so much more rapidly here? It’s the combination of Norther Yucatan’s corrosive dust and humidity.
Since the dust is typically removed from the air by rain, I would expect/guess that the first ½ hour or so of rain here would be alkaline because of our special dust, (depending on how heavy the rain is and how much dust has accumulated in the air). After that ½ hr or so, I would expect the pH of rainwater to stop being alkaline, and shift to being near pH 7 or lower.
Sounds like an experiment waiting to happen,
steve
Have I told you lately blog readers, how much I love you? I do. I knew I’d get some smart and informative responses.
OK, so the 2 catches of rain that I used to test the PH were cumulative, the container was set out before it started raining. I’ll do another test – no doubt tomorrow the way it has been raining every afternoon – and wait until later in the rain to catch the water and test.
I do have good, composted, black soil in the garden. I had hoped that it would keep the PH from the local limestone and my well water (which tests at a PH of 8 ) lower and allow better growth of tropicals. Today I bought a big bag of peat moss at Home Depot and intend to add that to the beds as it should lower the PH and the rain should carry that down into the soil.
The puzzle of the mint and what happened to my gardenia remains.
Oh, and Steve, if there is a lot of calcium carbonate in the soil here, what do you think of the idea of adding magnesia calcinada (oxido de magnesio) to the soil? Is there already sufficient magnesium in our soil?
Yucatan is a solid block of limestone, any dust that you have will have a high PH, as limestone has a very high PH. I’m voting on the dust, rain drops require a small bit of something to form a raindrop, dust fits that bill. It is true that most rain is acid to some degree, but living in a town with cement buildings all around, the rain and run-off may not be like country rain. I think your friend is dead on with her comment.
Manure has high acid levels but you have to be careful you do not burn up the plants. Manure has high salt content and can restrict the uptake of water in a plant. Sulphur will lower PH and it kills bugs, I use it on acid loving plants that need soil that has a low PH.
Jonna, we have mint (mente) in the garden. It’s in semi-shade and is in a pot. Miguel says it gets sick from the rain – he always rinses off our plants after a rain, especially the delicate ones like mint, tomatoes, and a few others. If there is lots of rain, he will stir up the earth around the roots.
We never had luck with gardenias either – for us it’s the wind, we don’t have anywhere to put it in full sun where there isn’t a breeze.
We put all our vegetable and fruit scraps in the garden, including the coffee grounds. With this climate, it breaks down really quickly (but we have lots of little hiding places so people don’t see it, not sure you have that but if you can get a compost drum, that might give you some great soil.
Good luck, you’re learning a lot about chemistry!
Mine is going crazy in the Chapala area. Growing in the shade of a mango. Only thing that bothered them were the leaf cutter ants and not enough water
I had a thought, then read all the other replies and lost it! oops! we are using a friend’s pool and were told to add check the acidity after big rains!
Those big gardenia looking trees are clavo de la India (Indian carnations) and are supposed to be fragrant in the evening. I want one for my roof.
My mint is doing okay so far…..but I have had lots and lots of it just die on me.
When the new hydrangea flowers I will have to see what color the flowers are!
regards,
Theresa
I find that mint does well when surrounded by mojito. That suggestion might not solve your gardening problem,but you might have more fun investigating!
I think that Kwallek is headed in the right direction with his response.
Here’s some detailed geology of what is likely contributing to the problem.
The northern part of the Yucatan pensinsula, which includes Merida, was once a coral reef thriving in a warm shallow sea. When adjacent land masses gradually rose over thousands of years, the ocean levels dropped, killing the reefs (made of calcium carbonate/VERY alkaline), leaving immense limestone masses as the bedrock at or near the surface.
The numerous sinkholes (cenotes) and caves which are found throughout much of Yucatan and Quintana Roo, were formed over thousands/millions of years as slightly acidic rainwater percolated through this limestone, gradually dissolving it.
That dissolved limestone forms the stalagtites & stalagmites in caves, but also moves, directly into the water which courses through the cenotes and caves, and through cracks in the rock eventually getting into the local soil.
So, the “agua potable” running through your garden hose, has likely been pumped up from an underground cenote source, which will always be highly alkaline.
In areas like this, it is common for an alkaline/basic “residue,” usually creamy white to grey, to accumulate around faucets and drain covers. You may also have a problem with the highly alkaline local water clogging up the tiny openings in any small appliances which heat water, such as coffee makers and steam irons. LIME AWAY, to the rescue, although some dilute muriatic acid will work, too.
A simple non-scientific way to check to see if your local water is very alkaline, is to boil a pot of it on the stove, until it all evaporates. If there is a white to grey residue left on the inside of the pot, that bubbles and dissolves easily when cleaned with either dilute muriatic acid or LIME AWAY, your water is very alkaline.
IMHO rain water would actually be preferred over the water coming from your garden hose, since it is evaporated water, thus essentially distilled water, up until the time it condenses and begins to fall from the clouds, catching any incidental particulates. It may actually be less alkaline than your tap water, unless it’s picking up a whole lot of alkaline dust as Kwallek suggests, from the grinding operations of Cruz Azul, et al, in making cement.
I’m guessing that acid lovers like camellias and azaleas, would need so much costly special care and soil amending in your area, that they are rarely found in nurseries or gardens there.
I currently live in an area which has somewhat acidic soil (farmers have to add lime to the fields for sugar cane). Our mint patch is gorgeous, but only for about 5-6 weeks in the spring when temps are mild. Once the intense summer heat and humidity kick in, the lush growth is halted in its tracks, and our fresh “tabouli” season is over for the year.
I know this was lengthy, but hope this helps. Good luck with all of your gardening projects. I always enjoy seeing the photos which you so generously share with your readers.
Let’s correct the record: manure does not tend toward acid. (Therefore, It does not generally make soil more acid, lowering ph). Here is research:
http://tinyurl.com/2dbhvuq
~eric.
All interesting comments, thank you. I do have a compost bin but I don’t add manure to it. I doubt I’d ever add fresh manure to anything in the garden, too many problems associated with that other than PH. I don’t have a source for fresh manure anyway and remember, this is a small city garden where smells are quickly noticed.
I agree that the water here is very alkaline, my well tests at around 8 although the city water is lower, in the high 7′s if I recall. I don’t use city water on the plants because I have a water softener and discovered that some plants were sensitive to the salt residue. I could test the GH and KH of the well water, I have the test kits for that, but I haven’t bothered. I know it is high, I’m not going to change that.
The swimming pool does turn green after rains, no matter the chlorine we use. Since I’ve been reading up on PH I have discovered that chlorine doesn’t work well in high PH, we also have an algicide that the pool guy uses once a week and we may start adding that after a rain.
Of course, this is the first run of more than one day without rain that we’ve had in weeks so I haven’t been able to do another PH test after a half hour of rain. Soon, no doubt.
BJ, you’d be surprised to see that azaleas, hibiscus and other acid loving plants are common in nurseries and fairly common in gardens. So, there is a solution. My hibiscus are doing pretty well but I do add coffee grounds and acid fert to them. The main hibiscus problem I have seems to be a mineral deficit, pale between the veins of the leaves. I’m trying the magnesium and it seems to have helped one of the hibiscus and part of a mint plant. Perhaps it is the imbalance of minerals, too much calcium not enough magnesium, that is the problem.
In fact, most shade tropicals are acid lovers since they are native to the compost covered floor of the jungle. I have a lot of gingers and heliconias that are doing fine. I think partly because I supplement with peat moss and bought good soil. I just bought another big sack of peat moss to add to the heliconia bed since I now know how alkaline the rain is.
I’m really interested in all of the responses, keep them coming. There is a solution and perhaps the first real problem is to figure out whether these are separate problems or related and what really is the problem. I’m still investigating.
Eric, I’m no expert on PH but as an old farmer, our rule of thumb has been that manure is a bit acid, to the left of 7. The abstract is pretty thin on its information but I would guess they are dealing with very acid soil and the manure was less acid and it brought it up some. We have acid soils here in Ohio,we put lime on our ground in the fall, manure in winter and it all kicks in together in the spring and summer. Again I’m no expert, it is just what I was taught growing up in the country.
The following about hibiscus problems is from an online source.
“Yellow leaves with green veins”
Yellow leaves with green veins are a clear indication of iron deficiency. Apply a good feeding of compost and manure, and scratch in kelp meal or seaweed. Iron chelate is often recommended specifically to target the deficiency. Dig this in lightly -never pack down tightly around the stem. Mulch, kept clear from the base of the stem, can also help.
The horticultural term for this malady may be “iron chlorosis.” Another online source for this problem suggested both a magnesium and an iron deficiency.
What a pleasant surprise to learn of azaleas in the Merida area. Maybe I’ll see them in bloom there someday. When is their bloom season? I’m guessing that it is much earlier than the early March season which we have here.
I’m guessing that you’ll find workable solutions to your gardening woes, and perhaps from an elderly local person who has a keen interest in plants, for medicinal, nutritional and ornamental purposes.
Hi Norm,
From one old farmer to another: I wanted to catch that generalization about manure and ph before it got tilled under. And I certainly don’t insist on being right. (We’ll leave that to the smart boys.)
The problem with learning is that half of what I learned is, pardon me, bullshit. But I don’t know which half! (And maybe the other half is cow manure, too, to use the polite term.)
Do you visit Merida?
~eric.
2ericc[at]rochester[dot]rr[dot]com
Eric,I have been to Merida about 6 times over the years, I am a ruin freak and back road and byway fan so Merida makes a good base to see Mayan culture.
Its funny about the manure, even though it is not all that acid by comparison to some manufactured acids, it was used as a tanning agent back to the stoneage.
Norm,
While smearing manure on a hide may eat the hair off it and cure the leather, that doesn’t establish the action or the substance as being acidic. (Alkalinity can be corrosive, too.)
Looking further, I found this from Penn State Extension:
Reported values for pH of manures are 6.9 for cage layer manure, 7.0 for dairy cattle manure and 7.5 for swine manure. Addition of waste feed, bedding or other materials to manure can affect these values. Also, because pH is influenced by the balance between volatile acids and ammonia that form during microbial decomposition of manure, the pH can go down or up depending on the conditions created by the management practices.
~eric.
Jonna,
I use cottonseed meal on garden plants that like a lower pH, as it also gives a nice bit of nitrogen. My potatoes love it, and it minimizes scab. While coffee grounds are a good source for lowering pH, useful on blueberries, for example, perhaps trying a different supplement such as cottonseed meal would help your mint and gardenias. It’s a bit pricey up north, as it is also used as a livestock feed. But maybe it’s cheaper in southern areas.
~eric.
What a great discussion!
Re, the gardenia — from your description, I wonder whether the culprit is root damage from insects, like beetles? We’ve had a lot of problems with that, though not with gardenias (never tried one, since I assumed I’d kill it).
I wonder to what extent the mint problem might be, at least in part, due to the heat.
I’m a little skeptical of the alkaline rain hypothesis — it makes a lot of sense at the beginning of the rainy season, when there is so much air-borne dust, but now not so much. I’ve noticed a big difference in the pool, for example, since the strong rains (much less accumulation of crud on the bottom, and the water is much clearer). Our experience, on a quinta just outside Merida, is that watering with well water keeps things alive, but few plants really take off until the rains. This seems to be the case no matter how much water one gives something.
We’ve found that the concept of “soil” in nw Yucatan is sort of an oxymoron….i.e., there just isn’t much, and what there is gets its nutrients washed out in short order (hence the slash & burn & milpa rotation of traditional agriculture). If growing directly in the ground, using top-mulches seems to help a lot (e.g., composted wood chips, leaves).
I wonder if anyone has actually grown azaleas in NW Yucatan — there are some nurseries that will truck in anything, and say that it grows here, but often that’s not the case.
Eric, if I ever see cottonseed meal here I’ll buy it but I’m doubtful.
mcm, the bamboo and heliconia are growing like weeds now that the rains have started. You have a good point there, if it were all that alkaline the heliconia at least would not be so happy. I do have wood chips and will add more after I get the peat on the beds. I have read that plants in the tropics – due mostly to the downpours rather than the soil – eat fertilizer way more than in other climates. I think it relates to the heavy rains occurring when the plant is growing rapidly unlike winter rains up north.
I wonder if the azaleas are grown mostly in pots? I see them blooming all winter in nurseries and I’ve seen them on people’s terrace – in pots though. Good point.
I’m not tied to growing only things that naturally thrive here, I am willing to make some changes to the environment for plants I like. If I can add the nutrients and acidify some areas in my garden, I’m willing to do it for the flowers.
I have seen some improvement in the mint with the addition of the magnesium, I’ve read that for a plant to absorb calcium it needs magnesium. Perhaps we have less of that and a plethora of calcium.
I now think that the gardenia died from nematodes, other root problems or being planted too close to the underlying limestone bedrock. I’m going to try another one in a different place, perhaps I’ll keep it in a pot and see how it does.
The mint, perhaps it is the heat. The one I have under the bananas in the shade is surviving though it doesn’t look great. The one in full sun looks worse. If they make it to winter they may look better.
Drgeo – the reason I want to grow mint is for mojitos – por supuesto!
bj – the first thing I did was bury some steel wool by the plants with the dark veins in case it was iron deficiency. That is what it would be in my northern experience, it didn’t seem to have much effect though and it has definitely rusted. I just found a better fertilizer that has more iron, magnesium, and other minerals. It’s sold for azaleas in fact, and I’m doing some trials with it.
Jonna,
Perhaps an experiment is in order? I wonder what the results would be if you collected rainwater and put a bare sprig of mint in a glass full of it, in a location which provides a mix of sun and shade. (Perhaps even using dark colored glass, or an opaque container would be in order.) Then, as a control, put a similar sprig into a like container of distilled water which can be found at the grocery or pharmacy. Mark them, and observe the differences in root formation between the two sprigs. (If you can’t establish the pH of either of waters, we can assume the distilled water to be neutral at 7.0.)
~eric.
I have all the test kits, it’s a pond thing. I also have Reverse Osmosis water and I will get another pot of mint – that doesn’t have whatever is wrong with the ones in my yard – and just water it with the RO, keep it out of the rain and see how it does.
Well, RO is good at removing particulate, but I don’t know what it does to pH. Using water which has a known pH (distilled water), and using a sprig (or sprigs) which have no roots, would be a better test, in my view. This way you can see the plant respond to two kinds of water: distilled, and rainwater. Minimizing the variables is what good science requires. Good luck with whichever approach you prefer.