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Soil too alkaline

Gillette, WY

I recently tested my soil (my self) and two things need fixing: need more nitrogen (easy enough, i think) and my ph levels are too high. I've researched and found that sulfur will make my soil more acidic. So I went to home depot and couldn't find anybody or any product to help me. What would you do? I've also heard coffee grounds, but I don't drink enough coffee make a difference. Is there any product I can order online or something I haven't heard of?

Anne Arundel,, MD(Zone 7b)

Adding organic matter of any kind will help. Oak leaves and pine needles are often criticized for adding acid but I am not sure how much of that is true.
Over here we have the opposite so offhand I don't know another, sulfur is the usual recommendation. There's no way you could drink enough coffee.

Oh have you seen this?

Everett, WA(Zone 8a)

It sounds like moderate amounts of Urea or Ammonium-based fertilizer will lower the pH slightly - just don't use too much or you'll burn plants.

Hmm, household ammonia will also kill slugs and their eggs: add nitrogen, acidify, AND kill slugs. A hat trick!

Gillette, WY

ammonia based fertilizer? at least that gives me a starting point for what to look for in home depot. I'm intrigued by the household ammonia trick. Have you tried this, RickCorey? I asked my mom if she had heard about that and she said she did! I just may go out there with a spray bottle and spritz my plots! No one on Dave's Garden has lead me astray yet! LOL! Thanks for the link, sallg. Lot's of useful info there.

Even though I agree I could never drink enough coffee, I've still been throwing all grounds and leftover coffee out there . I also got the word out to save me grounds, we'll see who comes through for me.


Anne Arundel,, MD(Zone 7b)

You're very welcome. Now I'd be cautious spraying ammonia around. Ammonia itself straight may burn or be toxic to critterettes. It will get converted to useable things. Ammonia liquid itself is a base (opposite of acid) though... isn't it? Who's the resident chemist?

Everett, WA(Zone 8a)

I agree that "diluted" is very important. Concentrated ammonia straight from the bottle would burn plants and even hurt soil life (like slugs!) I''m afraid I don't know what concentration would be safe. My main use will be to kill slugs..

At HD, if you get a knowledgable clerk, be sure to stress the final "m" in "Ammonium-based fertilizer".
Or more likely, if you say you need fertilizer for acid-loving plants, or to correct high-pH soil, he or she may knolw what you mean.

Hopefully, you have basic soil because everyone in the area has basic soil, so when you say it, they say "yeah, don;t we all, try this". I've never lived near basic soil in my life - I thought ALL soil was acid and needed lime every few years. Don't we all have acid rain?

my problem with buying fertilizer at HD or Lowes is that I hate to pay $30 when the usefull part might cost $15-20 at a farm coop, minus the pretty colored plastic bag and salesy blurbs on the bag. Unfortunately, they no longer like to sell ammoniujm nitrate to people they don't know, and I guess even urea can be used for bomb-making. That's what I used to use for very-low-Nitrogen soil. buy one 50# bnag of urea and they sprinkle a LITTLE every other week.

Urea can burn roots or wash away and can release something (I think Ammonia) in excess into soil if you use too much at one time. But it is cheap!

Ammonia (with no "m" at the end) is a base because if you mix it with an acid, it will accept an H+ from that acid.
Ammonia is neutral (NH3), in fact it's a soluble gas and can evaporate.
AmmoniuM salts have a charged Ammonium ion (NH4+) and some negative ion like Nitrate or Chloride.

If you add AmmoniuM salts to a basic soil, the NH4+ could donate an acid ion (H+ or H3O+) to the soil, sslightly reducing its basicity.

Probably, very slightly.

Anne Arundel,, MD(Zone 7b)

Good info- Why did we not think earlier of the "for acid loving plants' fertlizers?
Meanwhile I found vole tunnels and now want to spray MY garden with ammonia.

Deep South Coastal, TX(Zone 10a)

I have basic soil, average pH in our area is 8.5- 9.5 and some even higher. I have 6.9 in the garden now and it has taken 3 or 4 years to bring it down. Our water is also alkaline, so it is an ongoing problem, along with high sodium. Adding gypsum (a neutral) will slightly adjust high pH to a lower number and it will raise the pH of very acid soils, yet does nothing to near neutral soil. Elemental sulphur, available at garden centers (Espoma makes a good one) or from some big box stores like Sutherlands or Menards in 50 lb bags by MK company works well. Follow directions on the bag for your particular pH and the result you are trying to acheive. Fertilizer for acid loving plants also helps, with the granular kind being longer lasting, the larger the particles the longer lasting the results, but also slower to work in the first place. We have added sawdust from hardwoods like ash and oak, pine straw that has been composted, coffee grounds and regular composted straw and grass clippings to amend the soil. My compost usually tests around neutral (normal for most compost). You might also try a greenhouse supply company or farm store in your area. Southern Ag company makes liquid sulphur and comes in one gallon bottles which is mixed with water and used as a drench. Don't try to bring your pH down all at once, make it a long term goal and you will have healthier soil in the long run.

Some plants don't mind alkaline soil, for instance sweet potatoes. They don't like added sulphur. Some other plants may be sensitive such as curcurbits like melons. For regular potatoes we add about 10# sulphur per 100 ft of row, right in the row with the potatoes. They love it and it seems to cut down on scab and other potato diseases.

Be careful adding too much fertilizer or manure, you can get salt build up which is a double problem with alkaline soils.

Mixing an acid in your water with an injector system also works, but is dangerous if you don't know what you are doing. Phosphoric or sulphuric acids work well in this application.

Gillette, WY

I found this link. It says that Peat moss has a pH of 3.0.

Last year was when i dug up some plots (for the first time) I added peat moss and 10-10-10 fertilizer. This is all I did to amend the soil. I did not take a soil test and do not know what the pH might have been. I do know, however that I was pretty proud of my first garden, everything seemed to do well.

This year, I added a new plot and I did the same as the last year, added peat moss and fertilizer. The other older plots got compost (from HD) blood meal and more fertilizer. These were the plots I took a sample from bc I was worried all the plants robbed the soil.

SO... That makes me wonder why my pH is too high since I just added peat last year. Should I really add more? I'm kinda scared about the ammonia idea, even though I will look for some products with ammonium in it this next weekend.

Any thoughts on this peat moss idea?

Gillette, WY

Calalily, I didn't even think about going to a Ranch store! I live in a smaller town (well not really) and do not have a lot of options. But I always forget about that one. I think they even sell bags of manure. Thanks for all the product info. I think I will jot down everything you suggested and see what they got! If they have manure they must have some other gardening/soil products. what else do you use manure for anyways?

And, calalily, thanks for the confidence! If it has taken you years to get your pH where you want it, then maybe I will still have a nice garden and just continue to work on it. I think I may be worrying too much. What else is new?

Deep South Coastal, TX(Zone 10a)

I have been able to grow almost anything even though the pH has been a constant battle, the worst problem with high pH is nutrient tie-up. Some nutrients just are not available when the pH is too high and some are overabundant. Get a good soil test from your local extension office or soil test lab (we are in high ag area, so have a choice of several labs), have them check for more than pH and NPK. Have them test for zinc and calcium, sodium and some of the more inportant trace elements like manganese, magnesium, etc and make sure they do either a wet test or CO2 test which is more accurate. It may cost a few bucks, but is worth it in the long run, plus you won't be adding unnecessary things to your soil.

When I plant things that really need low pH, I just give them a little sulphur. The only things I can't grow are blueberries and raspberries (and things that need chilling hours which we don't have).

Gillette, WY

Calalily, what happens when the pH is too high? low production? small fruit? What problems have you had with plants that relate to the high pH?

Anne Arundel,, MD(Zone 7b)

Jenn, your pH can still be high after one application of peat.
Its easy to underestimate the effect of the many tons of soil underneath the zone where you have mixed in a few inches of amendment.
I'll leave the rest to Calla who deals with this issue hands-on.

Everett, WA(Zone 8a)

I was trying to figure out how elemental sulfer ("flowers of sulfer") could be a strong acid, since I thnik of it as pretty inert, or at least neutral.

Trust bacteria to eat anything! Some sturdy bacteria can oxidise that sulfer right to Sulfate. Yikes!

It would be sulfuric acid (H2SO4) if it didn't react with basic soil right away by donating some of its H+ to bases in the soil.

There is a "farm coop" even in a big city like Everett. You jusst have ot be carefull what you buy, becuase they know they caan make more profit b y selling chatchcas to Yuppies than bales of straw or bags of chicken feed. Don't buy the pretty 2-quart bag of sulfer on display on the shelf. Get a 50 pound bag from "the warehouse" and it will probably cost only slightly more. And they'll respect you more!

A coop or "feed store" would also be the place to find urea, ammonium nitrate or ammonium sulfate cheap. If you mutter thaqt your soil tested basic and low-nitrogen, they may trust you not to be a terrorist and sell them to you. Me, they look at like I'm the Unabomber and say "we're all out".

I don't know what it is - maybe the heavy black-frame glasses make me look like Frank Langella in "The Ninth Gate"

Wake Forest, NC(Zone 7b)

Farm supply store near me sells sulfur pellets for acidifying around blueberries. I bought a small bag from Nourse Nurseries because I was ordering some other stuff. My HD and Lowes people looked at me like I was crazy when I asked for sulfur. It has to be wettable sulfur.

Poughkeepsie, NY(Zone 6a)

Try your local smaller garden centers to find sulfer, they are a lot better often times than big box stores. If your PH isn't in the right range it can lock out fertilizers to the plants. And you'll be wasting your money on plant food that way. Also pick up a small bag of Esphoma Greensand. It provides a LOT of trace minerals to the soil that get depleted over time.

Deep South Coastal, TX(Zone 10a)

Greensand used in excess can raise pH, but is wonderful to add in small amounts for trace elements and potassium.

High pH by itself doesn't usually hurt the plant, but as the pH increases many nutrients are unsoluble and therefore unavailable to the plant. Usually these are iron, zinc, manganese, copper, boron and phosphorus. If your pH is greater than 8, especially if it is over 8.3, high sodium is usually a problem too. Excess sodium binds up potassium.
Easy with excess use of ammonium fertilizer trying to reduce the pH, it can cause magnesium deficiency.

When applying nutrients to alkaline soil, be sure to use chelated elements because if they aren't soluble, they will not be available. Soft rock phosphate is useless in alkaline soils. Ammonium sources of nitrogen can become unavailable fast, so use nitrate nitrogen for longer lasting availability to plants, or apply water soluble in small, frequent doses.
Hope this helps. I'm still fighting some deficiencies because I forget to amend the soil when I replant.

The soil test you need for high alkaline is the Olsen test, the others won't give accurate results. Be sure to also test for micronutrients.

Gillette, WY

Okay so this is what I did: I finally found some acid loving plant food. And that will have to do for now. l found a pine needle hookup and a coffee grounds one too! so I will just have to slowly work on it throughout the summer and year. This has been a really interesting thread for me though. A lot of info that I need to read over and over (LOL) I hope one day I will be able to give advice and be learned like all of you wonderful gardeners!

Everett, WA(Zone 8a)

>> pine needle hookup and a coffee grounds

That's good! These organic amendments contribute a little acidifying power and the organic matter itself is great for soil in many ways.

A thick pine needle mulch on top of soil moderates temperature swings in the soil and conserves water. It breaks up rain drops which keeps soil from crusting or eroding. As it breaks down slowly, or if you turn it under next fall, it will decompose and add organic matter to the soil.

I guess I would pile a mix of pine needles and coffee grounds together so they would compost, then 6 months later add the compost to the soil. But you can also mix coffee grounds directly into the soil between plants, or before planting and after harvest.

Does anyone top-dress with coffee grounds? When I put down 1" of very fine coffee grounds, they packed together and looked like they were sealing oxygen out of the soil. I decided I had better rake them in to the soil a little so the top layer would "breath".

Lots of organic matter is bound to help your soil life, water retention and probably even aeration. The 'acid lovers fertilizer' ought to help correct the basic soil faster than pine needles & coffee grounds unless you have LOTS of needles & grounds.

If plants still seem scrawny, it may be that too-basic soil IS locking up some nutrients. You might get a spray bottle and feed some complete soluble fertilizer like Miracle-Gro directly to the leaves. If you do that to just a few plants, and they perk up and look a lot better than un-sprayed plants, you know you are correcting the problem.

You could also keep your eyes open for "wettable sulfer", "flowers of sulfer" or "elemental sulfer". You may have to go somewhere with knowledgable clerks, like a co-op, "feed store" or farm supply store. A really good nursery ought to know what you're talking about, but they tend to charge more.

Deep South Coastal, TX(Zone 10a)

This thread was great for me also, did some more research and learned something myself. I love DG!

Anne Arundel,, MD(Zone 7b)

RC - Love that suggestion of foliar feeding!

Gillette, WY

RickCorey, Spray the fertilizer directly to the leaves! What a great idea! Wow! makes so much sense too. I can't wait to try that.

Also, about the wettable sulfur, I researched it, and it seems that it is primarily used for a fungicide? Is this correct? I found it online in pretty little bags. LOL

Everett, WA(Zone 8a)

Thnakls! Someone pointed out that foliar feeding is best used for diagnosing nutrient problems, or emergencyh fast-fixes, but that we should correct the underlying soil problem for best long term results. But esp;ecially if you're trying to m ake basic soil more acid, that sounds like a multi-year project. The "add plenty of acidic organics over several years" sounds like a solid plan.

>> wettable sulfur, I researched it, and it seems that it is primarily used for a fungicide?

I didn't know that. I'm learning a lot in this thread! The fact that there are soil microbes that turn neutral sulfer into sulfuric acid came as a shock to me ... but it makes sense.

I tolok up foliar feeding when I had some indoor plants in very unsuitable soil ... back in the 70s or 80s. I never knew for surfe whether they were chronically short of iron or magnesium. When they showed red petioles, I sprayed leaves with MgSO4 (Epsom salts?) AND a mix that had a lot of chelated iron. Perked them right up!

If I recall, spraying half with Mg and half with iron did not work as well. That kind of suggested that BOTH were not very available to the roots.

I always tried to make the pH neutral when I fertilized, but maybe they needed it a little acid. Anyway, that soil was HORRID for containers.

Deep South Coastal, TX(Zone 10a)

Yes, foliar feeding is a quick fix, but it keeps the plants alive while you fix the underlying problems. The nutrient deficiencies are what weaken and kill the plants.
You need elemental sulphur to reduce the alkalinity.

Laingsburg, MI

I recently discovered that our soil where our white pines are planted has a Ph of 7.0, and the pines need a more acidic soil. Long story short, a gentleman at Michigan State Univ., in the plant diagnostics dept., directed me to buy granular sulfur, the stuff used to supplement azaleas and rhododendrons, and sprinkle it around the trees up to the drip line at the rate of six pounds per 10 x 10 feet. Within a couple of weeks the yellowed needles were turning a light green. I was so thrilled to have saved our trees.

Just as an aside in case this pertains to anyone, the trees shd be supplemented with water during a drought or dry spells.

Hope this helps.

Everett, WA(Zone 8a)

>> granular sulfur

Granular?!? That's a surprise. I thought it had to be finely powdered, since it's so insoluble.

But clearly it worked well.

mid central, FL(Zone 9a)

i've been looking for a place to pose this question and i hope someone sees it here.

i have blueberries (a southern highbush variety) in pots. eventually they will go to a permanent location in the garden but my question is: knowing they need a higher acidity, can i use epsom salts instead of sulphur? i can pick up some sulphur at ace hardware but since epsom salts are magnesium and sulphur (sulphur is 12.5%), wouldn't that work okay?

Everett, WA(Zone 8a)

Don't trust my answer, but here is my theory.

Sulfer works because there are some potent soil bacteria that convert "elemental" sulfer into sulphuric acid. (S + O2 + H2O -> H2SO4. As the microbes get their energy by burning sulfer, they release lots of acidity (the H+ that was briefly combined with SO4- - )..

Magnesium Sulfate is already MgSO4, so bacteria an't oxidize it further opr release any H+.

But what do I know? There may be some other biological surprise where Epsom salts do create acidity!

Little Willie was a chemist.
Little Willie is no more.
For what he thought was H2O
Was H2SO4.

mid central, FL(Zone 9a)

so you're saying that epsom salts don't create acidity but sulphur alone does?

love that little ditty!

Everett, WA(Zone 8a)

That's my belief. But I only learned how "elemntal" sulfer worked recently, here at DG.

Until someone explained that strange bacteria oxidize the sulfer, I couldn't figure out how neutral, stolid sulfer could acidify anything. Really, it is food for bacteria, and THEY do the deed!

mid central, FL(Zone 9a)

thanks. i'm not sure i understand it all but thanks. :-)

Everett, WA(Zone 8a)

I would love to test it, and think about those little bac teria brwing up SULFURIC ACID, but everywhere I have lived has had acid soil, acid rain, and clay. Several bags of Dolomite Lime every few years was just "of course".

mid central, FL(Zone 9a)

i have sand.........sigh.
all my beds have been improved with truckloads of what passes for soil here and then i amend with bagged stuff.

Everett, WA(Zone 8a)

If I could teleport, I'd trade you 5 cubic yards of heavy clay for 5 cubic yards of sand!

Then I'd find a feedlot manure dump and telport both of us 20 cubic yards of cow manure.

mid central, FL(Zone 9a)

boy, i hear ya on that one!
gardeners have to make do with what we've got and then add as much as we're able....nobody ever said it was gonna be

Deep South Coastal, TX(Zone 10a)

We have "delta muck" and sand. When blended with compost makes perfect soil except the pH is 8.5 and because of limited rainfall we also have high sodium (which is what raised the pH to start with). Now I think I've lowered the pH too low for my sweet potatoes in one section! They aren't growing and won't green up. Can't win!

mid central, FL(Zone 9a)

what are you using for mulch? maybe whatever it is is robbing the sweet potatoes of nitrogen? just a thought.

Deep South Coastal, TX(Zone 10a)

I took them out yesterday and moved them, no new roots, no new growth. The plants were rooted cuttings put in the ground 5-21-12, mulch is our own compost which was about a year old when spread. I need to check pH today. Soil was "green" on top. Salad mix was growing before sweets.

We make our own compost, do not use broadleaf weed killer, so not contaminated and we do not use animal manure in the compost. We make tons at a time and it is turned with a front end loader when temps inside reach 165 (about once per week) and is not used on the garden until it stops heating up. We have compost in stages, from brand new to about a year old. No problems anywhere else, only 4 beds of sweet potatoes, 3 different varieties.

Everett, WA(Zone 8a)

>> We make tons at a time and it is turned with a front end loader when temps inside reach 165 (about once per week)

Drool, drool, envy!

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