Questions about Fertilizing And Ph..

jojosplants(9/ Tucson, Az.)January 24, 2013

Josh, Did I spell that right? It looks funny to me. ;-) Fertilizing? lol..

On to my questions. I see it talked about many times over here that if a solution doesn't provided Calcium and Magnesium then it should be added.

Often miracle grow is brought up, which is what I have at the moment. And the box is long gone, so I cant read it to see if it has these in it. :-(

I've seen Epsom salt and Gypsum suggested. But in what ratio's ? How much should be added to say a gallon of water at each watering?

And is the Gypsum added to the water or soil. My guess would be soil, and if so, should it be replaced from time to time, and about how often?

My little tree is currently in 5-1-1, and I goofed and forgot the lime, so is there anything else I should do?

I use rain water as often as possible, and it was suggested in another thread to add some tap water, which is interesting and I never would have thought to do. So from here out, I will do that.

I have also seen it suggested to test our water for PH. I know my water is horrible! So I do plan to test it.

Is it best to test before watering or the run off? I've seen both suggested.

So.. If I figure out how to feed it proper, plenty of sunshine, and TLC, I'm good to go right? :-)

Thanks all!

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Well it is a good thing you forgot the lime as you need to stop reading advice from people writing about most of the nation. I' sure it is good advice. Just not for the southwest where we suffer from alkaline soils not acid soils due to lack of rainfall.

Your tree may yet survive.

Stop adding anything. What is missing from your soil that needs to be added. Nothing I'd bet. But I know you don't know. Have your soil tested and find out. Then you can supplement it.

If it is a new tree you definitely shouldn't be fertilizing it. If it is a 3 year old or longer planted tree then maybe. But if you heavy mulch it with wood chips or bark and keep it annually mulched you probably never will have to fertilize it.

As for pH of the water you use, who cares. It probably runs around 6 from that CAP stuff, but the soil has enough buffering that water pH makes no difference. Rainwater is great. Nothing better. You get 11 inches of that split between August-Sept. and December-January. Unless you trap every drop that falls on your property and encourage street runoff into your yard, you have to come up with other water the rest of the year.

That water will be salty. So water heavily (down 4 feet) and infrequently. Hell, you live in a city with one of the leading water experts in the planet, Brad Lancaster living in downtown Tucson completely off grid. And a University that has tremendous resources available online for home horticulture on its Extension Coordination.

Here is a link that might be useful: Watering Guide in AZ

    Bookmark   January 24, 2013 at 4:56PM
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jojosplants(9/ Tucson, Az.)

But you did not read my post correctly or understand it.
My tree is not in the ground, or soil for that matter. It is in a mix referred to as 5-1-1. Pine bark fines, peat moss, and perlite.


    Bookmark   January 24, 2013 at 5:06PM
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Jojo....If you want your plants to thrive in a 'container' and in the 5.1.1 mix and you are using a fertilizer without Ca and Mg, you will have to add lime or use a fertilizer that provides it.

If you're making your own bark/peat soils, you would include dolomitic (garden) lime at the rate of 1 tbsp/gallon of soil, or 1/2 cup/cu ft.

If you're making the gritty mix and not using FP fertilizer or another soluble fertilizer that has Ca and Mg, include gypsum @ the same rates instead of the dolomite, then include 1/4-1/2 tsp of Epsom salts in your fertilizer solution when you fertilize.

Is is imperative that you supply the Ca and Mg for your citrus since soilless mixes are not like the ground soils in your area.

If you forgot to incorperate lime into your 5.1.1 mix, why not just scratch some into the surface and the sides of your pot? Works great for my plants.

Just rain water has done wonders on my citrus if I use fertilizers that provide all the nutrients my plants need. In fact, rain water has aboslutely no salts which I try to avoid from tap.

I would probably call your local municiple supplier and ask them for the pH of your water.
I found that mine was much to high, about 8.5 so I use vinegar to bring the pH down in my watering solution.
It's the soil in teh ground which one has to worry about as compared to the mix in a pot. For pots, it's the pH of your watering solution that is more important.

Gypsum is added to the mix Jojo and the Epsom salts to the water. I replace mine every spring in my pots but that is only in the gritty mix.

I would assume that it's what you add to your fertilizing solution before you water and it hits the mix than after it exits. Not sure on that one:-)
But mine thrive using this method.

Hope this helps Jojo!:-)


This post was edited by meyermike_1micha on Thu, Jan 24, 13 at 19:09

    Bookmark   January 24, 2013 at 7:05PM
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jojosplants(9/ Tucson, Az.)

Hi Mike!
To add the lime, I will have to go buy some. ;-) Which I don't mind, but if anything follows me home other than lime, I will tell DH my other Mike made me do it. ;-) lol...

If I add the lime, which I will, do I still add the Epsom salt to the fertilizer if I am using Miracle Grow.

I was thinking I had read to add the Gypsum to the 5-1-1 if it didn't have lime, and using MG, maybe I understood that wrong.

According to a water report included in a bill last summer, I know our PH is high. I will try and call or find my test strips from the pool. :-)

And yes, salt is high here too. I love my rain barrel and put as much of it as I can in soda bottles and such when we have a big rain, and it fills fast.

Thanks much !!
Hi to mom! and hugs to both!


    Bookmark   January 24, 2013 at 8:17PM
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greenman28 NorCal 7b/8a

Hey, Mike and JoJo!
Yes, Mike nailed it. Gypsum for Gritty, Lime for 5-1-1.
I'd get that Lime, since you're going to need it for future container mixes, as well.


    Bookmark   January 24, 2013 at 11:29PM
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jojosplants(9/ Tucson, Az.)

Hi Josh!
Good to see you!

Now what makes you think I will need it for future mixes? ;-) Would it be the fact that I have my eye on a new Pink Variegated? or the strawberries I bought a few days ago. :-) Tis the season. lol..

Thanks Josh! :-)

    Bookmark   January 24, 2013 at 11:50PM
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pgde(Tucson Zone 9)

Hey Jojo:

Firstly, the correct spelling of Ph is pH :-)

The above post by Fascist Nation (FN) contains a wealth of INCORRECT information concerning our pH and soil quality here in Tucson. I need to say that I don't have any container plants (and am writing this for the benefit of others that might be reading this post), and also Chemistry in college formed a large part of my degree.

First of all, the pH of our water (out of the tap)ranges from 7.9 to 8.6 depending on what part of town you are in (see Even if you are using well water, is would probably be in roughly the same range. Just FYI, "neutral" water, i.e. water that is neither basic or acidic is 7.0. And, the pH scale is logarithmic, so each unit change (say from 7.0 to 8.0) presents a change of 10 (see So you can see our water is quite basic, which is not what citrus thrive in (at least at is what several sources have said). In both water and soil, citrus do best in slightly acidic soil (6.0-7.0) with a corresponding acidic water (which is why some people add vinegar to their watering regime). Of course, with my plants, I do not have that luxury, being on drip irrigation. So I use garden sulfur pellets sprinkled around the base and dripline of the tree. While this is not an overnight solution, it will eventually lower the pH of the soil and offset the basic drip irrigation.

Secondly, the comment about "buffering". If anything, our soil is so basic (alkaline) that it definitely needs treatment before planting any thing directly (i.e. sulfur, etc). Otherwise, the tree will never reach its full potential because it will not be able to fully absorb any nutrients, including micros (especially iron). While it is recommended to use "native" soil in many publications, our soil is so basic and sterile (due to the ultraviolet radiation from the sun as well as lack of organic breakdown reactions), that some kind of organic addition is preferred (that does not contain peat moss). A mix of 1 part organic to 3 or 4 parts native would be okay (and don't forget about the additive to lower the pH).

Considering the Total Dissolved Solids (TDS) in and Hardness of our water, I would be very careful about adding any lime to container plants here in Tucson. Sorry Mike (please forgive me), but I disagree about a blanket statement about using lime or gypsum. In many other places in the US the water quality is neutral to slightly acidic, so lime is necessary. Lime is nothing more than Calcium Carbonate (limestone) that has been heated. Gypsum is nothing more than Calcium Sulfate and is generally used to add hardness to water for brewing beer, etc. Both are part of the TDS calculation. However, here (unless of course you are using bottled or softened water), I think the dissolved Calcium will do just fine. And, as a reminder if you are using common Salt (NaCl) in a water softener, do NOT use that water on your plants. It will build up and be eventually toxic, regardless of how much you flush. If your softener uses Potassium (KCl) as the softener, you are very safe in using that water since Potassium is not harmful to any citrus and in fact is supposed to make cell structures more cold resistant..... I wish I could afford to run my drip off my softened water.....

Finally, for those of you concerned about testing of rainwater. You may want to test it. Remember the "acid rain" events of the recent past? It is well documented that when Sulfur is burned (like in auto exhaust or even volcanoes, chemically speaking it is Sulfur Dioxide) and is absorbed by water in the upper atmosphere, it forms a dilute sulfuric acid. In fact, in the case of a major volcanic eruption, this is one of the biggest impacts as the sulfur gases are spread through the atmosphere by normal winds. So, while here you might not want to test your rain water, I certainly would in the LA Basin, Phoenix area or in the Midwest. While current air pollution technology has reduced the amount of sulfur dioxide in the air, acidic events still occur.

Hopefully this will help you understand what is going on. Feel free to ask any questions if this is confusing.


This post was edited by pgde on Fri, Jan 25, 13 at 0:56

    Bookmark   January 25, 2013 at 12:46AM
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Just ran into the same lime problem myself. I took the advice Mike just gave and scratched in a tbs of dolomitic lime just under the surface of the tree. So far so good. I'll repeat the process in the spring once I've moved the tree outside. I would imagine you won't want to scratch a full 1/4 cup all at once, it just seems like an awful lot for one time. After you've scratched it in, give the tree a nice gradual soaking.

My advice on the fert is just pick up some Foliage Pro from Amazon. The 9 bucks it'll cost you is worth the peace of mind. Lime or gypsum/epsom will supply the ca/mg you need though (and yes, MG does not contain them!).


    Bookmark   January 25, 2013 at 9:58AM
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hoosierquilt USDA 10A Sunset 23 Vista CA(10b Sunset 23)

Another point that should be made is this misconception that citrus are "acid-loving" plants. The are not. Citrus preferred pH range is on the neutral to slightly acidic range, 6.0 to 7.0. "The Biology of Citrus" by Spiegel-Roy and Goldschmidt suggests this mildly acidic soil pH of 6.0-7.0. They also note that you may obtain "satisfactory results up to a pH 8.0 or even somewhat higher." pg 148. There is a great message thread that was posted in this forum a few years ago by a couple of our very knowledgeable forum members, cebury, silica and redshirtcat (sadly, we don't see them posting as much as they did in the past, and I know silica, who has an extensive chemistry background, his information is extremely accurate and scholarly). The thread is "Citrus in alkaline soil" and very informative.

I can tell you that none of our California commercial citrus growers amend their soil for pH. Nor do they acidify their water for irrigation, and our commercial citrus grow just fine here in our more alkaline soils. Now, this is California, and citrus in the ground in Arizona may be different, your pH may be higher, and you may need to do some minor amending for pH to achieve optimal growth, but in a controlled situation with container citrus, your pH with 5-1-1 mix may not need further acidification with lime. There seems to be this conception that for some reason, you need to bring the pH down to 5, and that simply is not true for citrus.

Acid rain (as defined by rainwater with a pH less than 5.7) is usually something we see on the eastern seaboard, very, very unlikely to see here in the west, even in the Los Angeles basin area due to our alkaline dust particulate matter in the air, which neutralizes any rainfall that might be more acidic. It simply is not an issue here. If you do feel compelled to test the pH of your rainwater, you will need to purchase a very high quality pH tester, as the ones you can buy at your local garden center are notoriously inaccurate. Expect to pay in the $100 range for a decent one. Peter is correct about municipal water here in the west (and in other areas as well). It tends to be on the alkaline side, to discourage growth of certain organisms. But, I have never, ever had to acidify my water with my container citrus. My municipal water is about 7.5 to 7.8. You can check what your tap water's pH is by going to your local municipal water district's web site, and check out their annual report, which they are mandated to post. The only caution with tap water, is if you're inside tap water is softened with salt. In that case, I would use your outside tap water, which is usually not softened.

Patty S.

    Bookmark   January 25, 2013 at 2:04PM
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Lime does not acidify mixes and in fact sweetens it.

Most bark peat mixes without lime start out as low as 4.7 to 5.5 range.
That is why ALL commercial peat based mixes do add lime in order to bring pH to a range in which is required by most plants.

Many plants can't function properly in a container with a pH that low, and lime also provides the Ca and Mg needed for many plants to thrive that MOST fertilizers do not provide.

Here, you can learn about pH and other issues in soilless mixes that do not compare to that of ground dirt.


Here is a link that might be useful: Fertilizer Program for Containerized plants

This post was edited by meyermike_1micha on Fri, Jan 25, 13 at 21:36

    Bookmark   January 25, 2013 at 9:34PM
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hoosierquilt USDA 10A Sunset 23 Vista CA(10b Sunset 23)

Exactly, Mike. I have Al's three posts clipped, they have been very helpfu. Very few plants prefer that acidic an environment, azaleas, rhododendrons, camellias, blueberries. Citrus just aren't in that category. A more neutral pH is preferable. In fact, it was from you, I believe, that I found out about Dyna Gro's Foliage Pro, which has the micros. And, now that Osmocote has come out with their "Plus" formulation, that has a pretty close 5-1-3 NPK ratio, plus those micros, my container citrus have never looked better. I attribute the incredible come back of two of my rather rare citrus to your container advice. Love both those products. I'm also using this fertilizing combination with my potted figs with very good results as well.

Patty S.

    Bookmark   January 26, 2013 at 12:11AM
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greenman28 NorCal 7b/8a

Yes, the 5-1-1 mix - due to the variation in bark pH primarily - can have quite
a low starting pH, which is why the addition of Lime is favored to bring the pH up
into the target range, while providing Calcium and Magnesium in the proper ratio.

Once the mix itself is in a range conducive to nutrient uptake, we really need only
concern ourselves with the potential alkaline creep caused by basic tap-water and accumulating
solids from fertilization. Thus, it is a good idea to test one's water and one's fertigation
solution. Indeed, in certain parts of the country, tap-water may not need to be acidified.


    Bookmark   January 26, 2013 at 11:51AM
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jojosplants(9/ Tucson, Az.)

Hi Everyone!
I'm sorry I didn't get back here yesterday. I've been sick.
There's some great info here and I will read it all again a little later when it's quiet here.

Peter! You made me laugh!! Thanks for the help with spell check. ;-) Can't believe I did that! lol...
Are you getting the rain? Very wet here!

Hi beaconquest! Thanks for your help and stopping in! I will get it and scratch it in. When I went to make my mix for this tree, I spaced it out, and then found my lime had gotten wet. It's a brick now. lol..
We are headed to Home Depot today, so hope to find it.

I do plan on FP later in the spring. Just on a very TIGHT budget at the moment and have MG to use up.

Have a great day friends, and I will look in a little later and read better what you all had to share.
Kinda hard to concentrate with a stuffy head and cartoons in the background. If you can call them that ! Nothing like what we grew up with. yeesh...


    Bookmark   January 26, 2013 at 11:58AM
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pgde(Tucson Zone 9)

HI Jo -- yes, fortunately, we got .52" here today. Hurray! At least the west side didn't get everything :-)

And Hi Josh! My only point in regards to adding lime was that the alkaline water here in Tucson might also neutralize the low pH of peat-based soil mixes thus negating the need for additional lime and subsequent build-up of basic salts. And, for some reason, I seem to remember a series of postings about not using peat-based soil mixes due to its variable water absorption rates if the peat dries out. If not true, perhaps my mind is slipping .... Of course, since I don't have any citrus in containers (all my container plants are cactus with the exception of a real banana plant), this is not germane for me. I just thought it important to discuss pH and what has worked for me here in the desert clime. We used well-rotted horse manure (of which we have an endless supply) for adding some organics to the soil column here. If anybody in Tucson needs any, just let us know :-)

BTW, I hope everybody's citrus here in Southern Arizona made it through the recent hard freeze nights. I only had a few leaves impacted on my variegated pink lemon. And surprisingly, no obvious impact on my key lime!!!!

Enjoy the beautiful clouds today!


    Bookmark   January 26, 2013 at 6:55PM
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greenman28 NorCal 7b/8a

Hi, Peter, I add organics to my yard/garden all the time :-)

As far as the water bringing the acidic bark or peat into a favorable range...
I don't think it would be enough, soon enough. Better, in my opinion, to include
the Calcium and Magnesium (in the form of Lime) at the start, and then "neutralize"
the water in the fertigating solution later (if needed).

As for peat-based mixes, there's a whole host of reasons to avoid them, uneven wetting
and drying sharing the top spot on the list with the fine particle size that compacts easily.
As a result of the uneven wetting and drying and compaction, roots are often choked off
or dry off when pockets of soil dry, compact, and shrink around the roots. When re-potting and
attempting to remove old peat-based soil from a plant, the compaction of the mix leads to serious
root-trauma/root-loss - even when the old mix has been softened with a warm bottom-watering/soaking.
Peat-based soils are also difficult to properly flush, and this can cause excessive salt build-up
during the Winter when heavy watering of peat leads to weeks of soggy potting mix.

The final reason, in my opinion, to avoid peat-based mixes is the foul tea-colored effluent that flows
out of the mix when watered. This effluent stains carpets, tables, decks, concrete, et cetera.
I prefer a clean growing experience.


    Bookmark   January 27, 2013 at 3:45PM
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jojosplants(9/ Tucson, Az.)

Hi Everyone!
Still haven't had a chance to read this in full but will try soon. Trying to catch up on cleaning I got way behind on with being sick. Ugh!!!!!!!!!!!!

Horses? ;-) Don't really need the manure at the moment, but if you ever need help exercising them, I would love to! :-)

Glad your tree's came through!! My little in ground had all the leaves turn crunchy! Stems seem O.K. Waiting to see if it perks up. May replace it soon. I use the surrounding soil in the well for greens. Which i'm anxious to plant.

Well... anyway!
I found a water report in the current bill, and online. so I will post a link.
Seems our PH is 7.9 . According to the one in bill... our hardness is about 204, but the report I found online for the South west side of town (my side) is much higher.

I know our water is hard, from the calcium build up on everything!

Chilly, rainy, cloudy today, and yes, enjoying the clouds! So pretty the way the rush across the sky!


Here is a link that might be useful: Tucson/ south west water report (my area)

    Bookmark   January 28, 2013 at 6:07PM
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Josh: Fantastic points! I always like what you have to share:-)

Hello Jojo! How's it going? Have you had time to read yet?
You busy gal you!
I hope that what was said here has helped you along with your trees.
How are they doing these days? Citrus have a way with either going down hill very fast or all of a sudden grow like weeds!

It's snowing here today in what seems to be a too long of a winter for me already. Oh, I can't wait until I can go back to the days of watering every tree at once very liberally!
I just found a stash of, get this, 'Osmocote Plus' at the local True Value store for 12.50 compared to 24.95 everywhere else and a bunch of 'Slugo Plus'Yahoo.


    Bookmark   February 3, 2013 at 12:30PM
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hoosierquilt USDA 10A Sunset 23 Vista CA(10b Sunset 23)

Wow, what a great find, Mike! Osmocote is not cheap. I ended up buying a big bag of it on It ended up being less expensive to make the big investment, and buy a 25 lb. bag, so I've got enough for a bit :-)

Patty S.

    Bookmark   February 3, 2013 at 10:46PM
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jojosplants(9/ Tucson, Az.)

Hi Mike,
Yes, I finally did. :-) It's a great discussion with the exception of one.

I read the link you provided on Fertilizing program.

Looks like I may want to add a little vinegar to bring the pH down a little in my water?

And will add a little Epsom salt until I can get the FP.

Tree is doing O.K. ;-)Just kind of hanging out. lol.. no new growth, but no decline either. I moved it back outside after our several days of freeze passed.

My in ground tree seems to be a gonner. I put it in a pot for now and set it back in the bed. I am going to look for another. I was anxious to start planting greens, and it's in the center of that bed. lol... so all I will have to do is lift the pot, put in a new tree. Got Swiss chard and spinach planted yesterday. :-)

I'm sick of winter too! And were not near as cold! Snow!! you poor thing! stay warm!!

What a great deal on the Osmocote!! I'll be at a True Value today. I'll have to take a look!

Patty! 25lbs! I guess you are set for awhile. :-)

Well... Need to motivate for now. I hope you all have a great day! Stay warm!!


    Bookmark   February 4, 2013 at 10:14AM
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