Mixing Chelated Iron with Epsom Salt

[Tropicalgrower89]

Hello everyone,

I've been applying sequestrene 330  chelated iron to my mamey sapote trees and I have a bag of epsom salt which I have not been using.  Can I mix epsom salt (magnesium) with the chelated iron for future soil drenches? If I can how much?
I am using 5 gallons worth of water (5 gallon bucket) for the soil drench.


Thank you,

[Cookie Monster]

I suggest 2 things:

 - Get a soil test to ensure that your iron is low. I've found that some south florida soils actually have adequate iron. Manganese seems to be the lacking micro-nutrient.

 - The soil test will tell you how much calcium is in your soil. Assuming you have sand (not marl), you can get rid of the excess calcium and drop the ph by applying sulfur. Once you get the calcium saturation down, you can fertilize very efficiently with just gold old 8-3-9 with minors.

Granular sulfur (Tiger 90) can be purchased for around $15 per 50 pound bag. Depending on the CA concentration of your soil (and your lot size), 2 - 3 bags once a year should be sufficient to flush out the calcium that gets introduced via watering.

To give you an idea of effectiveness, I was able to drop the pH on the soil on my neighboring lot from 7.4 to 2.4 :-). I went a little overboard (1 ton worth of sulfur :-), but that should show you the effectiveness on sandy soil.

If you move to Miami and get stuck with marl, then you'll have to go back to chelated iron :-).

You can get a soil test from Spectrum Analytics for $14 (the S3 ag test). They use the same extraction method as UF, which is adequate for calcareous soils. Results are delivered elctronicall within 24 hours of receipt, and you can get fertilizer recommendations for a specific crop (eg, mango).

[Cookie Monster]

PS -- you're better off using K-mag (sul-po-mag) than epsom salt. K-mag includes potassium, which needs to be in balance with mg. Too much mg will lead to K deficiency, and K is normally already deficient in our soil. K-mag is about $15 / bag from Diamond R.

[Tropicalgrower89]

Cool. Thanks Jeff. 

[bsbullie]

Depending on the mskeup of your soil and what the tests shoe, the Tiger Sulfur should be applied like a fertilizer to your entire yard.  It will help keep the levels more stable overall and you will not need to apply as often.  Like once every few years.

[Cookie Monster]

Yep. In my case, I have to do it once every year to every 2 years, since the irrigation water adds Ca back into the soil. It takes a few months to take affect. It's a great quick knockdown of calcium, which then allows your sulfated fertilizers to work.

The soil I trucked in from palm beach county had a some bits and pieces of concrete rubble (very little -- golfball sized and smaller), and the sulfur turned it to white goop, presumably because it washed away all the calcium in the cement :-). The little bits and pieces of sea shells (smaller than bb sized) also disappeared. (The larger pieces are still there.) The stuff is magic.

Laying down a couple of bags of Tiger 90 once a year is waaay easier than doing drenches and foliar sprays :-). Don't go that route unless you absolutely have to. Get rid of the Ca and then just throw down 8-3-9 once a month (or mulch like a mad man like I do :-).

Depending on the mskeup of your soil and what the tests shoe, the Tiger Sulfur should be applied like a fertilizer to your entire yard.  It will help keep the levels more stable overall and you will not need to apply as often.  Like once every few years.

[Tropicalgrower89]

I'm fairly sure that my soil is acidic. It is very deep fine sand. As a matter of fact, it looks identical to this soil classification: http://ocreedy.net/index.php/pomello-series/

I don't think I'll need to do any sulfur applications. In a month or so, maybe sooner, after I save up a few $$$, I'll sign up to the spectrum analytic sight and test my soil.

[Cookie Monster]

I've found the soil data explorer to be highly inaccurate, and sand can lose its acidity really quickly either via disturbance (eg, building activities, or tilling -- as has happened in the sugar cane farms that are no longer acidic) or via watering (which is laden with ca+). And, if you see any "sea shells" in there, the probability is extremely high that your soil has been disturbed from its natural state and is actually alkaline.

Sand has a low buffer capacity and its ph can sway really easily one way or the other -- easy to acidify but also easy to saturate with calcium. That's good because you can effect a quick ph drop with sulfur, but it's bad because irrigation water can make it alkaline really quickly. Fairchild actually experimented with this, where they trucked in highly acidic soil from northern florida. The acidic sandy soil became alkaline within about a year (and they were adding acid to the irrigation water!). The acidic clay soil held out a little longer (due to the higher CEC), but its ultimate fate is the same. http://fshs.org/proceedings-o/2002-vol-115/146-149(Zhang).pdf

I have tested soils with pH below 6 here in south florida, so I know it does exist, but it's kind of a rarity in the disturbed / built-up areas. If your soil is acidic, you should be able to just plunk down good old granular iron sulfate (assuming that you are indeed iron deficient, which may or may not be a valid assumption). A number of SoFL soils that I've ran through spectrum analytics have actually had high levels of iron. Manganese seems to be the micro that is most often lacking. So, without a soil test, you're sort of shooting blindfolded :-).

And, iron is only part of the picture. If you have plenty of iron but are lacking in boron or potassium for example, you're still going to experience low yield.

I'm fairly sure that my soil is acidic. It is very deep fine sand. As a matter of fact, it looks identical to this soil classification: http://ocreedy.net/index.php/pomello-series/

I don't think I'll need to do any sulfur applications. In a month or so, I'll sign up to the spectrum analytic sight and test my soil.

[Tropicalgrower89]

I've found the soil data explorer to be highly inaccurate, and sand can lose its acidity really quickly either via disturbance (eg, building activities, or tilling -- as has happened in the sugar cane farms that are no longer acidic) or via watering (which is laden with ca+). And, if you see any "sea shells" in there, the probability is extremely high that your soil has been disturbed from its natural state and is actually alkaline.

Sand has a low buffer capacity and its ph can sway really easily one way or the other -- easy to acidify but also easy to saturate with calcium. That's good because you can effect a quick ph drop with sulfur, but it's bad because irrigation water can make it alkaline really quickly. Fairchild actually experimented with this, where they trucked in highly acidic soil from northern florida. The acidic sandy soil became alkaline within about a year (and they were adding acid to the irrigation water!). The acidic clay soil held out a little longer (due to the higher CEC), but its ultimate fate is the same. http://fshs.org/proceedings-o/2002-vol-115/146-149(Zhang).pdf

I have tested soils with pH below 6 here in south florida, so I know it does exist, but it's kind of a rarity in the disturbed / built-up areas. If your soil is acidic, you should be able to just plunk down good old granular iron sulfate (assuming that you are indeed iron deficient, which may or may not be a valid assumption). A number of SoFL soils that I've ran through spectrum analytics have actually had high levels of iron. Manganese seems to be the micro that is most often lacking. So, without a soil test, you're sort of shooting blindfolded :-).

And, iron is only part of the picture. If you have plenty of iron but are lacking in boron or potassium for example, you're still going to experience low yield.

I'm fairly sure that my soil is acidic. It is very deep fine sand. As a matter of fact, it looks identical to this soil classification: http://ocreedy.net/index.php/pomello-series/

I don't think I'll need to do any sulfur applications. In a month or so, I'll sign up to the spectrum analytic sight and test my soil.

Oh okay. Thanks for the info. I've always knew that soil close to any concrete structure can be alkaline due to the concrete excreting lime, but didn't know that well water can raise the pH. Lately, I have been using the well sprinkler system due to the recent lack of rain. Not the best alternative, but it is better than city water as far as I know. So far, I have not run into any sea shells, just an occasional small rock close to the house. I don't notice any iron deficiency. I just do iron soil drenches as part of maintenance for the mamey trees, along with cypress mulch, black kow, and NPK (palm fertilizer) applications. I'm following the UF (IFAS) mamey sapote care protocol. I'm definitely going to do a soil analysis using a sample from a spot in my yard that has not been covered with mulch, fertilizer and manure to get a true reading.

[Cookie Monster]

OK. I'd be curious to see the results.

I've found the soil data explorer to be highly inaccurate, and sand can lose its acidity really quickly either via disturbance (eg, building activities, or tilling -- as has happened in the sugar cane farms that are no longer acidic) or via watering (which is laden with ca+). And, if you see any "sea shells" in there, the probability is extremely high that your soil has been disturbed from its natural state and is actually alkaline.

Sand has a low buffer capacity and its ph can sway really easily one way or the other -- easy to acidify but also easy to saturate with calcium. That's good because you can effect a quick ph drop with sulfur, but it's bad because irrigation water can make it alkaline really quickly. Fairchild actually experimented with this, where they trucked in highly acidic soil from northern florida. The acidic sandy soil became alkaline within about a year (and they were adding acid to the irrigation water!). The acidic clay soil held out a little longer (due to the higher CEC), but its ultimate fate is the same. http://fshs.org/proceedings-o/2002-vol-115/146-149(Zhang).pdf

I have tested soils with pH below 6 here in south florida, so I know it does exist, but it's kind of a rarity in the disturbed / built-up areas. If your soil is acidic, you should be able to just plunk down good old granular iron sulfate (assuming that you are indeed iron deficient, which may or may not be a valid assumption). A number of SoFL soils that I've ran through spectrum analytics have actually had high levels of iron. Manganese seems to be the micro that is most often lacking. So, without a soil test, you're sort of shooting blindfolded :-).

And, iron is only part of the picture. If you have plenty of iron but are lacking in boron or potassium for example, you're still going to experience low yield.

I'm fairly sure that my soil is acidic. It is very deep fine sand. As a matter of fact, it looks identical to this soil classification: http://ocreedy.net/index.php/pomello-series/

I don't think I'll need to do any sulfur applications. In a month or so, I'll sign up to the spectrum analytic sight and test my soil.

Oh okay. Thanks for the info. I've always knew that soil close to any concrete structure can be alkaline due to the concrete excreting lime, but didn't know that well water can raise the pH. Lately, I have been using the well sprinkler system due to the recent lack of rain. Not the best alternative, but it is better than city water as far as I know. So far, I have not run into any sea shells, just an occasional small rock close to the house. I don't notice any iron deficiency. I just do iron soil drenches as part of maintenance for the mamey trees, along with cypress mulch, black kow, and NPK (palm fertilizer) applications. I'm following the UF (IFAS) mamey sapote care protocol. I'm definitely going to do a soil analysis using a sample from a spot in my yard that has not been covered with mulch, fertilizer and manure to get a true reading.