# Soil Remediation Guidelines



## g-man

*Soil Remediation Guidelines*​
You got your soil tested. They gave you some high level recommendations that you need to increase X or Y, but how do we do that? This article will try to address the techniques or approach to remediation based on your soil test and soil needs.

*General​*For most cases, don't try to remediate the soil during the winter if your soil freezes. Products applied to frozen soils might not travel deeper into the soil and could get washed away. *Do applications when the grass is actively growing*. Also avoid applications in the peak of summer under drought conditions since it might lead to more plant stress. This is a marathon and unless you are deficient (rare) most of the amendment we do is to get the soil to an ideal condition.

The soil test results from the lab might have some recommendations in the bottom. Those are normally for amount for the *entire year*. The standard practice is to limit the application of nutrients to be no more than 1lb/ksqft/month.

Lastly, the recommendations are for soil applications and not for foliar. Do not use these rates for foliar applications unless you *immediately* run the irrigation to wash the product off the leaves.

*pH*​We need to start with the pH. Most of the soil recommendations depend on your soil pH. As previously discussed, a pH around 6.0-7.0 is in the sweet spot.

_If pH is less than 6.0_, then it will need lime. Your soil test should tell you how much lime to apply per ksqft. The guideline is no more than 50lb/ksqft every 6 months, unless you are using a fast acting lime. *For a fast acting lime, follow the bag recommendations.* There are 2 types of lime, dolomitic and calcitic. Dolomitic limestone is a mix of calcium and magnesium; while calcitic is mostly calcium. Most soils do not need magnesium, too much can cause the soil to become too hard and it cannot be removed from the soil. Unless the recommendation was to also increase the magnesium in your soil, use calcitic to increase your pH. For nitrogen, a low pH soil will benefit from using ammonium nitrate (34-0-0) at no more than 3lb/ksqft/month. Avoid applying other products withing 2 weeks of lime application.

_If soil pH is above 7.0_, then the best way to reduce it is with elemental sulfur at 5lb/ksqft per hot weather season (once a year in northern states vs twice in Houston, TX). Why? Elemental sulfur needs a microbial breakdown to convert it to sulfuric acid and release the hydrogen which is what reduces the soil pH (more info  in this Ohio State article). Too much elemental sulfur without the microbial activity can lead to accumulation and too much being released at once (hurt your lawn). There are other ways to reduce soil pH and this Purdue article describes it and this Iowa State article.

But (there is always a but), lowering pH in the soil might not be possible/cost effective. If the soil has enough calcium carbonate, the quantities needed of elemental sulfur are too much. This article describes a study that tilted 240lb/ksqft of elemental sulfur. It dropped the pH by 0.5, but it increased over the years. Continuous application might keep it there (but at 5-10lb/year?) and using other techniques (citric acid) will help.

*High pH techniques*​Having a high pH is not the end of the world. You can have a nice lawn with a high pH, as many of us do. It just needs some adjustments. The main issue with high pH is that iron is not as available via the soil. When iron is not available, then chlorosis starts (yellow lawn) due to the lack of chlorophyll. We work around it using foliar application of iron (FAS) so it is absorbed by the leaves (bypass the soil). The other option is to use a chelated source of iron. It is more expensive and might not work too well in the really high pH. Using Ammonium Sulfate - AMS (21-0-0) at no more than 4.7lb/ksqft/month as the nitrogen source will also help due to a slight acidifying effect.

*Phosphorous*​If your phosphorus is low, then you can use:

Triple superphosphate (TSP) 0-46-0 - Apply at no more than 2lb/ksqft/month

For low pH soils you can use:
Diammonium phosphate (DAP) 18-46-0 Apply at no more than 2lb/kqft/month but account for the nitrogen being applied 0.36lb N/ksqft. It will slightly increase the pH for a short term and then it will decrease it.

For high pH soils you can use:
Monoammonium phosphate (MAP) 11-52-0 - Apply at no more than 2lb/ksqft/month, but account for the nitrogen being applied at 0.22lb/ksqft. It will slightly decrease the pH.

Another option is to use biosolids (eg. Milorganite) or organic sources. They will take longer to break down and be part of the soil, but they do work.

An option from big box stores is to use a fertilizer called "starter fertilizer". These normally have a higher percent of P than N and can be used to increase the P levels without too much nitrogen feeding.

*Potassium*​For potassium there are two main options:

Sulfate of Potash (SOP) 0-0-50. Apply at no more than 2lb/ksqft/month. This will also provide some sulfate sulfur the plant needs too. It can be hard to find. Go to the hometown folders in the forum to ask someone local to your state for sources.

Muriate of Potash (MOP) 0-0-60. Apply at no more than 1.6lb/ksqft/month. MOP can be harsh into the soil(chloride), but it is widely used by most fertilizer blends (eg. Scotts). Try to find the SOP since it is better, but don't sweat it.

Potassium Nitrate 13-0-44. Apply at no more than 0.5lb/ksqft/month. The nitrogen is in the nitrate form, so it moves fast and leaches thru the soil. It is applied in liquid form and needs irrigation after to avoid foliar (4oz/ksqft foliar max). Thanks Greendoc for the info.

KMag or SulPoMag are also sources of potassium, but the include magnesium. Most soils dont need the magnesium, so this is not an option for most.

*Iron*​Once the soil pH goes above 7.0, iron is not as available. Soil applications of iron are just a waste of money. As explained above, use FAS or chelated irons for the high pH soils.

For soils below 7.0, you can also use FAS. You can also use any other source of iron per the bag rate. Avoid applications with moist/wet lawn, since it can be absorbed via the leaves and cause a black lawn. After sweeping the concrete, run your irrigation after application to clean the leaves if the lawn was moist.

This article from Harrells is a great read on soil iron in general. The irony in iron

_Warning_
Iron stains. It will stain your concrete driveway, patio, etc. Be careful how you apply it and where you mix it. Chelated sources of iron stain less or not at all.

*Sulfur*​Sulfur in the form of sulfate is an essential nutrient the plant needs. If you need to increase it, then Sulfate of Potash or Ammonium Sulfate will be good options. Elemental sulfur can also be good, if your soil pH can handle it.

*Gypsum*​Sometimes there is a desire to adjust the calcium without impacting the pH. We use gypsum for this. You can put down 20-30 lbs/ksqft of gypsum every 60 days. Keep the applications of P and K apart. Gypsum is 21% Ca by weight.

*Micros*​Research on micros is very limited. Most of the micros ranges were extrapolated from the ag side (eg. corn). I normally recommend to leave them alone, unless you are seeing a lawn problem (eg. yellow lawn) and all of your other soil items are in range.

*Balanced fertilizer*​Sometimes we refer to a balanced fertilizer. This means that the ratio of Nitrogen, Phosphorus and Potassium is equal. It is a mix of the products listed here (check the label) and ready to be applied from a bag. These products are easy to find in most stores.

Applications rates (maximum per month)
10-10-10 - 10lb/ksqft
12-12-12 - 8.3lb/ksqft
13-13-13 - 7.7lb/ksqft
16-16-16 - 6.25lb/ksqft
20-20-20 - 5lb/ksqft

Licensed Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)
https://creativecommons.org/licenses/by-nc-sa/4.0/


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## SNOWBOB11

Excellent write up @g-man.


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## npompei

Wow thanks @g-man I was just looking up my results from this past Fall and stumbled onto this new post. Timely!

So to clarify a few things:
1. I have low P & K and I read above what items to put down - but if I am going to put those ingredients down this coming Spring, would it be smart to just use a balanced Fert with Nitrogen? I remember reading on here that using Nitrogen during the Spring green up may be a bit excessive. Is that true? And if so, can I put down the P & K at the same time?

2. My lawn is new, just did reno/new construction this past Fall. So maybe adding some Nitrogen in the spring and going with the balanced fert may not be a bad idea?

3. And when is the best time to get fert down? I have my game plan for getting Prodiamine down in late March early April but curious how the fert timing matters when using a PreM?

You guys rock, thanks


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## g-man

Spring nitrogen can cause excessive grow and sacrifice root carbohydrates. The idea is to maintain a healthy grow (clip yield). A balance fert is an easy way to apply NPK. But it might force too much grow on an established lawn.

You have a young lawn. It doesn't have a robust root system yet and it is trying to grow and the established. It will need nitrogen, so don't shy away from spring nitrogen.

Prem should go down when the soil temps/GDD/ forsythia blooms. Apply nitrogen when the grass greens up and start to grow. A fast acting 0.20lbN/ksqft weekly is in the ideal frequency to avoid surge grow with a monthly application on a new lawn.


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## cr0ntab

This is treat, thanks so much!

Can we get this added to the top Sticky?

https://thelawnforum.com/viewtopic.php?f=24&t=3124


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## krusej23

Great job!


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## Greendoc

@g-man 2,2 lb of Potassium Nitrate per K is a lot at once. My usual application rate is 0.5 lb per k applied through the growing season. Nitrate N is way different in how it reacts vs the other sources. 0.3 lb Nitrate N can cause the grass to grow extremely fast. Showing effects within 3 days. I use Potassium Nitrate only because it dissolves in small amounts of water and contains no chlorides. SOP is far less soluble and safe to spread to apply a full pound ok K.


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## sean_h

Not sure I can trust a post that includes a link to an Ohio State article...


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## g-man

@Greendoc are you referring to a foliar application or a soil one (washing the leave off with irrigation)?


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## Greendoc

A soil application. 1 lb per K is the most I have applied at once to the soil. 4 oz is my maximum as a strictly foliar application.


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## Scagfreedom48z+

Gman fantastic write up. Do you know any websites selling reasonably priced potassium and phosphorus fert? I have 30m to cover. I have a spreadermate so I'm thinking that spraying would be the best way.

I tried out spoon feedings throughout the spring and fall last year to slowly increase it. I'm going to get another soil test once I can get out and get samples.


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## g-man

@ScaginMass I don't know of online sources at good prices. Look for a Helena or at site one or a place that sells to golf courses for liquid fertilizers. You likely will need irrigation if you want to spray the liquid fertilizers.


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## Scagfreedom48z+

Sweet thanks


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## TN Hawkeye

@g-man This totally going to sound like a stupid question but if your soil is high in a macro (potassium) is the best way to lower it to simply not apply fertilizer that contains it? Over time will the level decrease naturally?


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## g-man

It depends. Some elements are so tightly bound (chemical bond) that they won't leave (eg. Mg). Others move thru the soil and go deeper with water (eg. Potassium). Other can be removed when you bag your clippings and throw them away (eg. Phosphorus).


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## Harley

Very nice write up. I thank you for taking the time. You mention very high PH, what do you consider very high PH? Just got my test results and my front yard is 8.2 and my back yard 7.5. My thought is that these are slightly to moderately high. Thanks again


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## g-man

8.2 is high. pH is an log scale. The difference between 7 and 8 is that 8 is 10 times more alkaline.


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## B-Rad

Bookmarked...You the man @g-man!

Thank you for taking your time to write something like this out.


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## ShaneQi

@g-man

I was looking for Sulfate of Potash (SOP) 0-0-50 you mentioned, and I found this (in MQ's Liquid Lawn Fertilizing Plan):

https://www.greenwaybiotech.com/collections/water-soluble-fertilizers/products/potassium-sulfate-0-0-53?variant=4459785537

Is this 'Potassium Sulfate' the same as 'Sulfate of Potash'?
If so, the website says 'Soil: Apply 2 pounds per 100 sq.ft.'. Is that a typo? Because that's a LOT of stuff.


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## g-man

@ShaneQi it is the same thing and that's a typo. But this product online is extremely expensive and a powder. Others tried it and it is hard to apply.


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## ShaneQi

@g-man thanks for the heads-up, fortunately I haven't pulled the trigger. I will keep looking for SOP from other sources then.


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## doverosx

Thank you very much for this post! I've read it over and over, looking at my very weedy lawn, I think it would help me out to pull my pH down a bit and adjust a few things in my routine to start getting the slow pH reducing ball rolling.


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## PLOmaha

My waypoint soil test recommended applying potash in the fall. Should I wait? Or is it ok to apply now?


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## ellsbebc

ShaneQi said:


> @g-man thanks for the heads-up, fortunately I haven't pulled the trigger. I will keep looking for SOP from other sources then.


My local Site One sells 0-0-60. Might want to give them a try.


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## doverosx

PLOmaha said:


> My waypoint soil test recommended applying potash in the fall. Should I wait? Or is it ok to apply now?


Apply it now. If you can get a good 0-0-K loading you'll really help the plants endure stress.


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## PLOmaha

doverosx said:


> PLOmaha said:
> 
> 
> 
> My waypoint soil test recommended applying potash in the fall. Should I wait? Or is it ok to apply now?
> 
> 
> 
> Apply it now. If you can get a good 0-0-K loading you'll really help the plants endure stress.
Click to expand...

Thanks!


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## Texas_Bermuda

@g-man thanks for the great soil remediation guidelines write-up. I just received my first results from waypoint. i'm in central texas with notoriously high alkaline soil. my ph is 8.0, calcium is very high, and iron is low.

1) If i read your Guide correctly, i should use either FAS or Chelate as elemental sulfur might not move the needle with the high calcium. if so, should i do FAS or chelate? if chelate, what's the optimal kind, looks like EDDHA or HBED based on my ph=8.0?

2) and if i do ammonium sulfate 21-0-0, is that adding too much Nitrogen?

Thanks!
Will


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## Ohio Lawn

@g-man is there a wrong or right time to apply SOP and MAP?


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## g-man

> For most cases, don't try to remediate the soil during the winter if your soil freezes. Products applied to frozen soils might not travel deeper into the soil and get washed away. Try to focus in the months the grass is actively growing. Also avoid applications in the peak of summer under drought conditions since it might lead to more plant stress. This is a marathon and unless you are deficient (rare) most of the amendment we do is to get the soil to an ideal condition.


@Ohio Lawn this is in the first post.


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## Ohio Lawn

g-man said:


> For most cases, don't try to remediate the soil during the winter if your soil freezes. Products applied to frozen soils might not travel deeper into the soil and get washed away. Try to focus in the months the grass is actively growing. Also avoid applications in the peak of summer under drought conditions since it might lead to more plant stress. This is a marathon and unless you are deficient (rare) most of the amendment we do is to get the soil to an ideal condition.
> 
> 
> 
> @Ohio Lawn this is in the first post.
Click to expand...

Thank you. I didn't see that.


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## csmitty

Great write up and just what I was looking to see. I'm a 7.1 on the ph with high calcium. I have some yellow/lime green spots, would that be a good candidate for a FAS application? I already have some AS i've been putting down.

I'm also low on Phosphorous, being at 7.1 would the TSP be ok or should I go with the MAP?


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## ricwilli

MAP 11-52-0 - Apply at 2lb/ksqft. ---- Can I use this amount of MAP as a starter fertilizer for when putting seeds down?


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## g-man

@ricwilli did you follow the soil plan from your soil report? If so, then you don't need to do more. Otherwise, yes use MAP for your "starter".


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## ricwilli

@g-man So far 1 application of MAP and SOP has been put down per your recommendation. Another of both will be put down this Sunday. My goal is to put seed down mid August so I was asking about MAP because I noticed that everyone puts down starter fertilizer at seed down.


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## g-man

@ricwilli since you have bare soil, follow the Renovation Guide. I think the plan i wrote you involved MAP at seed down too.


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## turfnsurf

@g-man should SOP be applied in just the fall and spring? Or does the temperatures drive when you apply it?

I am good with the application rates. I bought my ammonium sulfate as well, and I am trying to get a sense of when to start applying both of these products.


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## g-man

> For most cases, don't try to remediate the soil during the winter if your soil freezes. Products applied to frozen soils might not travel deeper into the soil and get washed away. Try to focus in the months the grass is actively growing. Also avoid applications in the peak of summer under drought conditions since it might lead to more plant stress. This is a marathon and unless you are deficient (rare) most of the amendment we do is to get the soil to an ideal condition.


@turfnsurf this is in the first post.


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## turfnsurf

g-man said:


> For most cases, don't try to remediate the soil during the winter if your soil freezes. Products applied to frozen soils might not travel deeper into the soil and get washed away. Try to focus in the months the grass is actively growing. Also avoid applications in the peak of summer under drought conditions since it might lead to more plant stress. This is a marathon and unless you are deficient (rare) most of the amendment we do is to get the soil to an ideal condition.
> 
> 
> 
> @turfnsurf this is in the first post.
Click to expand...

@g-man my apologies. Not sure how I overlooked it. Thanks.


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## ricwilli

g-man said:


> *Potassium*​For potassium there are two main options:
> 
> Sulfate of Potash (SOP) 0-0-50. Apply at 2lb/kqft/monthly. This will also provide some sulfate sulfur the plant needs too. It can be hard to find. Go to the hometown folders in the forum to ask someone local to your state for sources.


@g-man This will give you 1lb of K /ksqft correct? Can this be applied all at once. I totally forgot about Potassium.


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## g-man

2lb of SOP/ksqft will give you 1lb of KO2/ksqft. Yes apply the 2lb of SOP/ksqft all at once.


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## ayylmao

g-man said:


> @ShaneQi it is the same thing and that's a typo. But this product online is extremely expensive and a powder. Others tried it and it is hard to apply.


can confirm... didn't see this mention before I bought a 2lb bag and tried to apply this weekend. immediately it was apparent that the powder was too fine to be applied thru a broadcast spreader so I tried a really old liquid power sprayer I had around...mixed success.

needless to say if anyone has recs for a better potassium product, or your go-to hardware for spreading, I'm all ears


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## Stoked33

@g-man Love your posts, wealth of knowledge. Thank you. Quick follow up if I may? I just received my first ever soil test and ph at 7.0....and I am very low on phosphorus. Looking at the remediation guide, is MAP the play? Thinking push down PH slightly, and raise P. Or is MAP ideal for ph levels higher than 7...and I should be looking into TSP?


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## schmendog

This is a great write up! Needed this badly.

@g-man was wondering if consideration should be given to different types of Nitrogen sources, due to potential effects on soil conditions?I was listening to the Matt Martin podcast and they were discussing how you should use different types of Nitrogen based on your soil conditions. Any thoughts on that? My PH is at 5.3 with very low Nitrogen.


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## VALawnNoob

Which Grass Factor podcast was it? The latest with Matthew of Guard Well Lawncare?


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## g-man

Nitrogen is not part of the soil remediation guide since it is so transient in the soil that it doesn't make sense.

The guide does recommend using AMS for high pH. I would use urea for the normal pH and fix your low pH with lime per the soil recommendation.


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## simplesimon

Just found this guide via @g-man's signature. Could this be made a sticky in the soil fertility forum or is it still a work in progress? Great guide!


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## g-man

It is in the sticky post in the soil folder.


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## simplesimon

g-man said:


> It is in the sticky post in the soil folder.


Thank you, I obviously need to do more reading!


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## bkscripto

Good evening all! My soil test showed that my P was at 3.08ppm, which is low according to the test. So I swung by my local farm store and got a bag of triple superphosphate 0-44-0. Laid it down at 2lbs per 1k, per this great guide.

I put a few granules in a cup of water just to see how it reacts. After 3 days the granules didn't seem to break down at all. Although the water did get "cloudy".

I assume this is normal? I've read that phosphorus takes a few months to work into the soil and give results, is that due to the slow melt time?


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## badtlc

Can you have too much P & K?


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## Wile

In short, yes. The upper limits I am not 100% sure on (will differ for each grass type and sometimes cultivars), but they can have detrimental effects on nutrient availability to the plant and/or nutrient uptake. Refer to the MLSN guidelines on minimum quantities.

https://turf.unl.edu/NebGuides/g2265.pdf


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## ceriano

g-man said:


> *Soil Remediation Guidelines*​
> You got your soil tested. They gave you some high level recommendations that you need to increase X or Y, but how do we do that? This article will try to address the techniques or approach to remediation based on your soil test and soil needs.
> 
> *General​*For most cases, don't try to remediate the soil during the winter if your soil freezes. Products applied to frozen soils might not travel deeper into the soil and get washed away. Try to focus in the months the grass is actively growing. Also avoid applications in the peak of summer under drought conditions since it might lead to more plant stress. This is a marathon and unless you are deficient (rare) most of the amendment we do is to get the soil to an ideal condition.
> 
> The recommendations are for soil modifications to be applied monthly. Do not use these rates for foliar applications unless you immediately run the irrigation to wash the product off the leaves into the soil.
> 
> *pH*​We need to start with the pH. Most of the recommendations depend on your soil pH. As previously discussed, a pH around 6.0-7.0 is in the sweet spot.
> 
> _If pH is less than 6.0_, then it will need lime. Your soil test should tell you how much lime to apply per ksqft. The guideline is no more than 50lb/ksqft every 6 months, unless you are using a fast acting lime. For a fast acting lime, follow the bag recommendations. There are 2 types of lime, dolomitic and calcitic. Dolomitic limestone is a mix of calcium and magnesium; while calcitic is mostly calcium. Most soils do not need magnesium, too much can cause the soil to become too hard and it cannot be removed from the soil. Unless the recommendation was to also increase the magnesium in your soil, use calcitic to increase your pH. For nitrogen, a low pH soil will benefit from using ammonium nitrate (34-0-0) at no more than 3lb/ksqft/month. Avoid applying other products for 2 weeks.
> 
> _If soil pH is above 7.0_, then the best way to reduce it is with elemental sulfur at 5lb/ksqft per hot weather season (once a year in northern states vs twice in Houston, TX). Why? Elemental sulfur needs a microbial breakdown to convert it to sulfuric acid and release the hydrogen which is what reduces the soil pH (more info  in this Ohio State article). Too much elemental sulfur without the microbial activity can lead to accumulation and too much being released at once (hurt your lawn). There are other ways to reduce soil pH and this Purdue article describes it and this Iowa State article.
> 
> But (there is always a but), lowering pH in the soil might not be possible/cost effective. If the soil has enough calcium carbonate, the quantities needed of elemental sulfur are too much. This article describes a study that tilted 240lb/ksqft of elemental sulfur. It dropped the pH by 0.5, but it increased over the years. Continuous application might keep it there (but at 5-10lb/year?) and using other techniques (citric acid) will help.
> 
> *High pH techniques*​Having a high pH is not the end of the world. You can have a nice lawn with a high pH, as many of us do. It just needs some adjustments. The main issue with high pH is that iron is not as available via the soil. When iron is not available, then chlorosis starts (yellow lawn) due to the lack of chlorophyll. We work around it using foliar application of iron (FAS) so it is absorbed by the leaves (bypass the soil). The other option is to use a chelated source of iron. It is more expensive and might not work too well in the really high pH. Using Ammonium Sulfate - AMS (21-0-0) at no more than 4.7lb/ksqft/month as the nitrogen source will also help due to a slight acidifying effect.
> 
> *Phosphorous*​If your phosphorus is low, then you can use:
> 
> Triple superphosphate (TSP) 0-46-0 - Apply at 2lb/ksqft every month the soil is growing
> 
> For low pH soils you can use:
> Diammonium phosphate (DAP) 18-46-0 Apply at 2lb/kqft but account for the nitrogen being applied 0.36lb N/ksqft. It will slightly increase the pH.
> 
> For high pH soils you can use:
> Monoammonium phosphate (MAP) 11-52-0 - Apply at 2lb/ksqft, but account for the nitrogen being applied at 0.22lb/ksqft. It will slightly decrease the pH.
> 
> Another option is to use biosolids (eg. Milorganite). They will take longer to break down and be part of the soil, but they do work.
> 
> Last option is to use a fertilizer called "starter fertilizer". These normally have a higher percent of P than N and can be used to increase the P levels without too much nitrogen feeding.
> 
> *Potassium*​For potassium there are two main options:
> 
> Sulfate of Potash (SOP) 0-0-50. Apply at 2lb/kqft/monthly. This will also provide some sulfate sulfur the plant needs too. It can be hard to find. Go to the hometown folders in the forum to ask someone local to your state for sources.
> 
> Muriate of Potash (MOP) 0-0-60. Apply at 1.6lb/ksqft/monthly. MOP can be harsh into the soil(chloride), but it is widely used by most fertilizer blends (eg. Scotts). Try to find the SOP since it is better, but don't sweat it.
> 
> Potassium Nitrate 13-0-44. Apply at 0.5lb/ksqft. The nitrogen is in the nitrate form, so it moves fast and leaches thru the soil. It is applied in liquid form and needs irrigation after to avoid foliar (4oz/ksqft foliar max). Thanks Greendoc for the info.
> 
> *Iron*​Once the soil pH goes above 7.0, iron is not as available. Soil applications of iron are just a waste of money. As explained above, use FAS or chelated irons for the high pH soils.
> 
> For soils below 7.0, you can also use FAS. You can also use any other source of iron per the bag rate. Avoid applications with moist/wet lawn, since it can be absorbed via the leaves and cause a black lawn. After sweeping the concrete, run your irrigation after application to clean the leaves if the lawn was moist.
> 
> This article from Harrells is a great read on soil iron in general. The irony in iron
> 
> _Warning_
> Iron stains. It will stain your concrete driveway, patio, etc. Be careful how you apply it and where you mix it. Chelated sources of iron stain less or not at all.
> 
> *Sulfur*​Sulfur in the form of sulfate is an essential nutrient the plant needs. If you need to increase it, then Sulfate of Potash or Ammonium Sulfate will be good options. Elemental sulfur can also be good, if your soil pH can handle it.
> 
> *Gypsum*​Sometimes there is a desire to adjust the calcium without impacting the pH. We use gypsum for this. You can put down 20-30 lbs/M of gypsum every 60 days. Keep the applications of P and K apart. Gypsum is 21% Ca by weight.
> 
> *Micros*​Research on micros is very limited. Even research on how low Phosphorus levels can be an issue is currently on going. Most of the micros ranges were extrapolated from the ag side (eg. corn). I normally recommend to leave them alone, unless you are seeing a lawn problem (eg. yellow lawn) and all of your other soil items are in range.
> 
> *Balanced fertilizer*​Sometimes we refer to a balanced fertilizer. This means that the ratio of Nitrogen, Phosphorus and Potassium is equal. It is a mix of the products listed here (check the label) and ready to be applied from a bag. These products are easy to find in most stores.
> 
> Applications rates (maximum per month)
> 10-10-10 - 10lb/ksqft
> 12-12-12 - 8.3lb/ksqft
> 13-13-13 - 7.7lb/ksqft
> 16-16-16 - 6.25lb/ksqft
> 20-20-20 - 5lb/ksqft


Is the nitrogen in DAP slow release? Can I spoon feed it in combination with urea?


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