Accidentally used hydrated agricultural lime - how to fix this?

solid7(9b)May 18, 2014

I was building a soil, and made the classic mistake of buying a lime based on the advice of the local so-called "organic gardening expert" at the store down the street. I asked for exactly what I wanted, didn't get anything near what I wanted. (my fault) So anyway, I've already dosed a batch, and I'm not about to throw it out. So how do I fix this mess? Is it as simple as balancing out the calcium with magnesium?

Thank you

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greenman28 NorCal 7b/8a

Toss it and start over.

Josh

    Bookmark   May 18, 2014 at 2:11PM
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johns.coastal.patio(USDA 10b, Sunset 24)

You did buy an agricultural product? I see that the recommended dose for Bonide is:

"Once a year, mix one (1) tablespoon of BonideâÂÂs Hydrated Lime in one gallon of water and apply as you would normally water."

If you are somewhat near 1 tablespoon per pot, you are somewhat near a normal dosing. Water thoroughly [or better, soak], maybe a few times, before planting.

If you are way over 1 tablespoon per pot, who knows. Maybe water a few times and test the pH.

This post was edited by johns.coastal.patio on Sun, May 18, 14 at 14:54

    Bookmark   May 18, 2014 at 2:49PM
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solid7(9b)

Dosing isn't the problem. I added approximately 1 tablespoon per gallon of soil However, the hydrated lime is suppoed to be more of a quick fix for things like blossom end rot on tomatoes - not as the basis of a soil.

I'm still having a bit of a hard time believing that this batch is lost. I'm going to be very stubborn to the notion of tossing it. Let's have some more input before we go that route...

    Bookmark   May 18, 2014 at 3:08PM
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solid7(9b)

By the way - the product that I purchased was "Hi-yield" horticultural hydrated lime. Apparently, this is what the earthbox people like to use. (they add about 3 cups of it on top of their mix - seems a bit extreme)

    Bookmark   May 18, 2014 at 3:10PM
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johns.coastal.patio(USDA 10b, Sunset 24)

"the hydrated lime is suppoed to be more of a quick fix"

I understand what you are saying, but with the fast action, dosing is important.

Say you had put in more like a cup per gallon of soil. That would be equivalent to 16 dosing all at once, and in fast action it would drive the soil to be very alkaline.

With 1 tbs per gallon of soil, we are just like putting 1 tbs per gallon of water, and then pouring that all through a 1 gallon pot. That might be a bit extreme (1 gallon to 1 gallon) but in the ballpark.

"they add about 3 cups of it on top of their mix - seems a bit extreme"

You're right. For a fast acting product, now we are talking about 48 times normal dose.

I found the label for Hi-Yield (link) and it recomments:

"Apply 1 pound per 30 square feet on slightly acid sandy soil and incorporate in top soil."

So yeah, 3 cups sounds crazy.

[By the way, I might not remember everything from my Bachelor of Science in Chemistry, but I at least have that background. The parts that I haven't forgot might apply ;-)]

This post was edited by johns.coastal.patio on Sun, May 18, 14 at 15:22

    Bookmark   May 18, 2014 at 3:19PM
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Ohiofem(6a Ohio)

I just got an Earthbox for Christmas and started using it this year. From my reading in the Earthbox forum, they specifically warn people not to use hydrated lime. Also there was a discussion on this forum a few months ago by someone who said he burned his plants badly by using hydrated lime in his 5-1-1 instead of dolomitic lime.

That said, I did use a small amount of hydrated lime in a soil mix I concocted many years ago when I didn't know what I know now, and it didn't kill my plants. I probably used 2 tablespoons in a five gallon pot. I don't think my tomatoes did great, but they didn't die. If you are set on using the mix you've made, maybe you could dilute the effects by doubling or tripling the other ingredients and thoroughly mixing in your limed mix. Maybe if you flush the mix well with plain water and wait two weeks for the reaction to settle down before planting, you might be OK.

Here is a link that might be useful: See page 2 of the Earthbox instructions under dolomite

    Bookmark   May 18, 2014 at 3:33PM
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johns.coastal.patio(USDA 10b, Sunset 24)

Again, speaking as an ex-chemist, we want to use the "fast acting here."

If you can submerge a pot in a larger pot of water, soak for an hour, "fast acting" should be over.

[You want to do this soak before planting, because this fast action is what burns plants, what makes hydrated lime infamous.

I agree that hydrated lime in pots is a bad combination. The thing about slow release lime(s) is that they are slowly releasing alkalines as other things, like bark might be slowly releasing acids. They cancel each other over time.]

This post was edited by johns.coastal.patio on Sun, May 18, 14 at 15:44

    Bookmark   May 18, 2014 at 3:35PM
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solid7(9b)

I'm not really in a rush to use this batch. We're a minimum of a month away from planting. I can wait.

Not sure what to say about the EB thing. This is a local nursery who claims great things with their recipe. My big mistake was being in a hurry, and not reading up before taking the package. It's way too low in Mg to be dolomitic, and I should have been more careful.

So, back to the question... Will this issue be sorted by adding in some epsom salts, and waiting? Or shall I just start working on feeding microbes, and let the issue take care of itself? (this is organic medium)

    Bookmark   May 18, 2014 at 3:47PM
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johns.coastal.patio(USDA 10b, Sunset 24)

Hydrated Lime is Calcium Hydroxide.

Pretty much anything "hydroxide" is very reactive when water hits it. The risk with mixing it dry, planting, and using it later, is that water hits those powders as you "plant and water thoroughly."

This reaction we are talking about adds calcium, but it's most violent effect, the one that "burns" is that it makes the soil suddenly alkaline.

I'm thinking that something similar to that BonideâÂÂs dose mentioned above can be gotten over just by soaking and draining. If you have a pH kit you can test at that point, and if this is a critical crop, you can get one.

Now on the secondary issue of magnesium and Epson Salt - not all organic soil mixes add those, but some do, and others apply it as a liquid fertilizer.

    Bookmark   May 18, 2014 at 4:10PM
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VWFeature(ZONE9Bakersfield, Ca)

Its more soluble and more alkaline (thus reactive/corrosive) than regular lime, CaCO3. Lime itself is pretty alkaline, can burn plants. WHen the CaOH has water added, it slowly absorbs CO2 from the air, converting to CaCO3. (H20+ CO2=> HCO3- + H+ ; Carbonic acid- soda water is a weak acid. ) adding an acid (H2CO3) to a base (Ca(OH)2) gives you a salt, in this case CaCO3, + H20
They talk about 'slaking' the CaOH- which is adding water and letting this happen. If you have a paste w sand, you get Roman mortar; if its in a lot of water you get powdered lime in water.
Basically, useable, just needs to be diluted more.

    Bookmark   May 18, 2014 at 4:25PM
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mckenziek(9CA)

If you haven't yet, you should measure the pH. Maybe there is no problem to begin with.

Here is some background info that may be of use to you.

Hydrated lime is calcium hydroxide (a base). When used in mortar, it gradually absorbs CO2 from the air. The process is very slow, and really only works when there is enormous surface area and sufficient moisture. If the mortar is too wet, it will not harden, because there are no air pockets by which to absorb CO2. Submerged in a few inches of water, the calcium hydroxide will keep for years (or decades) as "lime putty."

Anyway, after the mortar absorbs CO2 from the air, the calcium hydroxide reacts to form calcium carbonate, which is ag lime. In mortar, the calcium carbonate binds sand together to form a hard, strong solid.

I would speculate that you can quickly and safely convert the hydrated lime to ag lime by adding CO2. For example, just pour in a copious amount of soda water.

Or keep the mixture moist, but not water logged, and stir it regularly (maybe once per day). In a week, the hydroxide will be all gone, either neutralized by acids in the soil mix, or converted to ag lime by the process above. Once that happens, you should be good to go.

Adding an acid such as vinegar will certainly neutralize the hydrated lime. You would want to go slow and check the pH often.

--McKenzie

    Bookmark   May 18, 2014 at 4:28PM
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Ohiofem(6a Ohio)

So, back to the question... Will this issue be sorted by adding in some epsom salts, and waiting? Or shall I just start working on feeding microbes, and let the issue take care of itself? (this is organic medium)

No, it won't be sorted by adding Epsom salts. The issue is that hydrated lime has probably made your mix too alkaline. Epsom salts will have no effect on that. We have no idea what your potting mix or fertilizer, if you plan to use it, contain. They may contain enough magnesium already. But hydrated lime in a high enough concentration may interfere with the uptake of magnesium and other minerals. It may also kill the microbes you're counting on in your mix.

But if you trust the nursery that sold you your mix, why don't you ask them what they recommend?

    Bookmark   May 18, 2014 at 4:39PM
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johns.coastal.patio(USDA 10b, Sunset 24)

I think we three, VWFeature, McKenzie, and I are basically on the same page, but remember the headline purpose for lime in potting soil is to raise soil pH.

We do that either becasue we want to grow alkaline loving plants, or because other elements of the mix are themselves slightly acid: "Sphagnum peat moss is a stable organic material that holds 15 to 30 times its weight in water and decomposes very slowly. It contains about 1% N but little is released because it breaks down so slowly. It has a pH of about 4 so lime must be added to the mix to along with sphagnum peat, at the rate of 8.5 lb. per cubic yard of peat to neutralize the acidity.

Similarly, per tapla, "The pH of pine bark fines generally ranges from 4.7 as a low, to 5.1 as a high."

The action of that hydrated lime will be to react against all the acids it finds in the soil.

Update: but of course soaking and draining, much will just wash away. Hydrated lime would be very soluble compared to the mineral limes that are preferred. This difference is what makes one fast acting, and the other a long term agent (depending on granular size, lasting up to years).

This post was edited by johns.coastal.patio on Sun, May 18, 14 at 16:48

    Bookmark   May 18, 2014 at 4:44PM
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solid7(9b)

@Ohiofem - "But if you trust the nursery that sold you your mix, why don't you ask them what they recommend?" - Not really sure what your intentions are stating the question like that at the end of a post. (so I'll give the benefit of the doubt that it wasn't intended to be abrasive - although that's usually how such statements are worded) The fact is, I didn't say anything about trusting them, I said that I asked for something, and didn't get what I asked for, and it's my fault for not being a little more diligent before walking out the door. If I trusted them, I wouldn't be posting here.

The mix that I've made is not 5-1-1, but it's based on pine bark. I was hoping that someone knowledgeable would give me a fairly good assurance that it should neutralize and/or rinse out. Just want to make sure. I plan to keep it watered and drained for a month or so before use.

    Bookmark   May 18, 2014 at 6:00PM
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Ohiofem(6a Ohio)

Sorry. I honestly wasn't trying to be snarky. You said you bought your mix from a local nursery who claims great things about their recipe. I made the perhaps mistaken assumption that you trusted them enough to buy their mix, and the further assumption that the organic expert from the store down the street who recommended the hydrated lime was familiar with the recipe you are using. I have no idea what that recipe is, but maybe the people who sold you the stuff have a reason to think it would work. I don't know why this discussion became contentious. I was only intending to share what I know.

    Bookmark   May 18, 2014 at 6:34PM
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solid7(9b)

No, they're just salespeople, selling the brands they carry. They gave me the wrong product, and I didn't check close. Again, totally my fault.

I'm making the mix, they carry stuff for Earthbox. They're totally geared towards that line, and apparently, can't think outside "the box". Of course, when I called back and I told them I need "dolomitic" lime, they told me it was the same thing. So I know that this place is limited from now on to only what I know they have...

    Bookmark   May 18, 2014 at 8:57PM
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greenman28 NorCal 7b/8a

Ace Hardware usually carries Dolomitic Lime.

Josh

    Bookmark   May 18, 2014 at 10:24PM
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solid7(9b)

Thanks for the tip, Josh. Will check them out tomorrow.

    Bookmark   May 18, 2014 at 10:28PM
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seysonn(8a WA/HZ 1)

Also both HD and Lowes in my area carry dolomitic lime. That is what I use in my 5-1-1.

    Bookmark   May 19, 2014 at 12:49AM
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solid7(9b)

Lowes and HD in my area do not have the dolomitic. Only another nursery about 25 miles away, and they only carry it in 25lb bags.

    Bookmark   May 20, 2014 at 7:20PM
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greenman28 NorCal 7b/8a

What is the problem with a 25 lb bag?

I bought a 40 lb bag for $6 a few years ago....

Josh

    Bookmark   May 20, 2014 at 9:11PM
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Ohiofem(6a Ohio)

The problem with getting the right lime for adding to a potting mix is similar to the problem many of us have in finding pine bark "fines." It goes by different names in different places. In fact, I have never seen dolomitic lime sold under that name. I usually by Espoma garden lime or Fertilome agricultural lime. Both are actually dolomitic lime, but the only way to tell is to read the label and see if it contains both calcium and magnesium. Our local Home Depot and Lowes sell big bags of "pelletized lime." That is some times dolomitic (with magnesium) and other times calcitic (with no magnesium). You could actually use the lime without magnesium if you supplement with Epsom salts or a complete fertilizer that includes magnesium when watering. The only product you don't want is hydrated or "fast acting" lime.

    Bookmark   May 21, 2014 at 10:20AM
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drew51 SE MI Z5b/6a

I would use the rest to make a Bordeaux mix. Excellent fungicide. But I have plants that could benefit, you may not? Most batches are huge too! It has to be used fairly quickly.Funny story behind it's creation. It was used in Bordeaux France to keep people from eating the grapes from a local vineyard. Passer's by kept picking the grapes. So they came up with the copper-lime mix as it makes the grapes taste bitter. Soon it was noticed that downy mildew was absent from the sprayed grapes. A problem brought to France from American grapes.

    Bookmark   May 21, 2014 at 3:55PM
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solid7(9b)

The big problem I have with the big bags is that they aren't $6, and I don't want to store any more stuff. (not real big on hoarding) The bags that are sold at the nursery is $38 for a 40lb bag. It's finely pulverized, and there's no doubt that it's dolomitic. I know about the Calcium to Magnesium ratio, but I just didn't check. (got in a hurry) I wish I could find the Espoma or other brands here, but they just aren't around.

So there you have it. I have a big tote full of great potting mix with hydrated lime. I'm going to just wait it out, and not make that mistake again. Although I might look into that "Bordeaux" mix. Because honestly, whoever it was that said that compost/worm tea gets rid of powdery and/or downy mildew - and that I wanted so desperately to believe - was just plain full of crap. LOL

    Bookmark   May 21, 2014 at 7:12PM
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greenman28 NorCal 7b/8a

I'm certainly no hoarder with a 40lb. bag of Lime.

I wouldn't pay that price for Lime, either. That's a bizarre price for that quantity.

Josh

    Bookmark   May 21, 2014 at 7:59PM
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greenman28 NorCal 7b/8a

I misspoke....it wasn't 40lbs, it was 50lbs :-)

    Bookmark   May 21, 2014 at 10:17PM
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drew51 SE MI Z5b/6a

Downy mildew is tough, sulfer doesn't even stop it. You have to use big guns or the organic Bordeaux mix. For your soil, you can buy battery acid, if your soil is too basic. Battery acid is cheap and will turn the lime to gypsum and neutralize the mix. Of course mix with water, and only use 4 or 5 drops at a time till it's good. I grow blueberries and sulfuric battery acid is always on hand to acidify my tap water. As is a PH meter, a must have of you ask me.

I myself never add lime to my mixes. Most plants like an acidic soil. It doesn't take long for your tap water to make your soil basic. No need for lime IMHO. Plus remember to wait 6 months for the lime to work in your soil. Ha! If you make your 5-11 mix, the lime will not reduce PH for 6 months. That info is all over the net. Why even bother? your tap water will reduce it in 6 months too.

http://homeguides.sfgate.com/long-lime-raise-ph-77660.html

http://www.noble.org/Ag/Soils/LimingQuestions/

http://homeguides.sfgate.com/long-lime-raise-ph-77660.html

    Bookmark   May 21, 2014 at 10:32PM
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greenman28 NorCal 7b/8a

Drew, those rates that you're talking about are for the ground.

Fine powdered Lime reacts faster with its greater surface area. In mixes with low starting pH, the LIme will also react faster. In container mixes where moisture can be maintained, Lime reacts faster.

The reaction can be measured within weeks if not sooner.

Josh

    Bookmark   May 21, 2014 at 10:51PM
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hairmetal4ever(Z7 MD)

I have some lime that is not specified as dolomite, but it doesn't say 'hydrated' either - it just says 99.9% Calcium Carbonate. Is that stuff OK?

    Bookmark   May 22, 2014 at 1:57PM
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Ohiofem(6a Ohio)

Hairmetal: That is calcitic lime and contains no magnesium. If you can find lime that includes magnesium, you'll be better off.

Drew: Your links are discussing adding lime to soil in the ground. Container mixes are not the same. All quality soilless mixes I know of contain lime and most recipes for home made mixes put forth by university extension agencies and popular gardening sites include lime. None of them say "wait a year after mixing." Do you think MiracleGro puts together their mixes and then leaves them in the warehouse for a year?

Here are just a handful of typical recipes that add lime.

Organic Potting Mix Basics (University of Illinois)

POTTING MIXES FOR ORGANIC GROWERS (University of Vermont)

Homemade Potting Mix (University of Florida)

Gardening in Containers (University of Georgia)

How to Balance pH With Lime and Peat When Potting (SFGate)

Global Buckets Potting Mix/Dolomite

    Bookmark   May 22, 2014 at 2:28PM
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johns.coastal.patio(USDA 10b, Sunset 24)

Those of us with a nominal pH of 8 on our water supply might sweat the lime a bit less.

    Bookmark   May 22, 2014 at 4:19PM
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hairmetal4ever(Z7 MD)

My tap water is pH 7.7 but I normally use rainwater if I can - which seems to run about 6.0 here. However most of what I grow are tree seedlings native to acid-soil areas.

    Bookmark   May 22, 2014 at 4:42PM
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solid7(9b)

Greenman28 - that is more lime than I'll use in a lifetime. I have to be honest - I do organic grows, and I really don't pay much attention to PH most of the time. I've had containers that had a little lime vs. another similar planting that didn't, and neither of them held any distinct advantage over the other, when it was all said and done. I'd rather mix a nice rich mix, and barring any super out of whack PH shift, just take my chances. If I had synthetic ferts and a 5-1-1 mix, maybe I'd need to be a bit more studious. But while I DO check PH, I usually don't sweat it. Just not liking the idea of wasting a batch of fine ingredients.

    Bookmark   May 22, 2014 at 9:55PM
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mckenziek(9CA)

I see this thread is still going on and on. Did you ever measure the pH?

--McKenzie

    Bookmark   May 23, 2014 at 1:10AM
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greenman28 NorCal 7b/8a

I make a lot of mix for family and friends when potting plants to give away, so the Lime goes a bit faster. I still have most of the Lime, of course, in a sealable 5-gallon bucket stored under my house.

Josh

    Bookmark   May 23, 2014 at 10:37AM
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solid7(9b)

Yes, I did measure the PH. It's almost 8.

    Bookmark   May 23, 2014 at 4:42PM
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mckenziek(9CA)

pH of 8 sounds pretty good.

I think the effect of the lime has already essentially run its course.

--McKenzie

    Bookmark   May 24, 2014 at 3:06PM
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solid7(9b)

You may be right. Just going to let that mix sit for a long time now...

    Bookmark   May 25, 2014 at 8:39AM
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Ohiofem(6a Ohio)

Please let us know what happens when you use it. I've been doing some research on the question of pH in container plants and found that some people think what really matters is the pH of your water and not the pH of your mix. If they're right, you may not have much of a problem. If you're willing to experiment, you might want to try using vinegar to make your fertigating water have a pH below 7. My water is pretty "hard" so I sometimes add up to a tablespoon of white vinegar to a gallon of water in preparing my fertilizer solution. If you're concerned about magnesium, you could also add Epsom salts.

    Bookmark   May 25, 2014 at 11:42AM
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solid7(9b)

No, I usually water with rainwater and compost/worm teas made from rainwater. As I said before, I normally pay very little attention to PH, (growing organically) other than in the beginning, and my results are none too shabby.

I think there is a good deal of truth to the PH of the water issue, because I hot composted some pine bark with alfalfa hay earlier this year. You'd think it would be fairly acidic, but it PH'ed at almost dead neutral. The only thing I put on it was our well water, which is 8+.

    Bookmark   May 25, 2014 at 12:07PM
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