# High Potassium only for fall fert?



## TLowe (9 mo ago)

From what I have read potassium is good for root strength and helps with the stress of heat or cold weather. Seems like high potassium fert would be good for cool season lawns as summer approaches. Most of the fall labeled ferts have the high potassium. Should I not use the high potassium fert right now? By high I'm talking 10 percent potassium.


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## Virginiagal (Apr 24, 2017)

It's fine to use potassium now. Just don't apply more than 1 lb of K per 1000 sq ft in an application. Water it in.


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## TLowe (9 mo ago)

Virginiagal said:


> It's fine to use potassium now. Just don't apply more than 1 lb of K per 1000 sq ft in an application. Water it in.


One pound seems low vs what the fall fertilizer recommends at 3.2 pounds per 1000 sq ft. 
What would to much potassium hurt? Would more potassium be beneficial for TTTF in the summer? 
Please don't take this as arguing with you. I'm trying to learn I appreciate your comments. ✌


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## g-man (Jun 15, 2017)

Fertilizer have a salt content. High rates can hurt/kill your lawn. No need to apply potassium in the summer if your soil levels are ok.


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## TLowe (9 mo ago)

g-man said:


> Fertilizer have a salt content. High rates can hurt/kill your lawn. No need to apply potassium in the summer if your soil levels are ok.


Ok thanks!


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## Virginiagal (Apr 24, 2017)

If you have a soil test saying you need 3.2 lb of potassium per 1000 sq ft, you can divide that into three or four applications.. Keep at least a month between applications. The recommendation would be for a whole year. I find it hard to believe that a fertilizer bag would recommend 3.2 lb of potassium in a single application.


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## TLowe (9 mo ago)

Virginiagal said:


> If you have a soil test saying you need 3.2 lb of potassium per 1000 sq ft, you can divide that into three or four applications.. Keep at least a month between applications. The recommendation would be for a whole year. I find it hard to believe that a fertilizer bag would recommend 3.2 lb of potassium in a single application.


Your right I misread the bag. Its 20 -0-9 to be spread at 3.2 pounds per 1000 sq feet. 
Does this sound a safe rate ?


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## g-man (Jun 15, 2017)

3.2lb of product times 9% (0.09) = 0.28lb of K. That would be safe since it is less than 1lb of k.


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## TLowe (9 mo ago)

g-man said:


> 3.2lb of product times 9% (0.09) = 0.28lb of K. That would be safe since it is less than 1lb of k.


 Yes that's way under I see now. I'll have to remember how to figure it like that. 
Thanks 👍


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## Virginiagal (Apr 24, 2017)

3.2 lb of 20-0-9 will also give you 0.64 lb of nitrogen. Here's an article from Purdue on fertilizing Indiana lawns:
https://www.agry.purdue.edu/turfnew/pubs/ay-22.pdf
For spring/summer a mostly slow release fertilizer is better than a quick release. As the article says, go light in the spring, little or none in the summer, heavy in the fall. Leaving clippings on the lawn returns the nutrients in those clippings to the soil.


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## Deadlawn (Sep 8, 2020)

g-man said:


> *Fertilizer have a salt content.* High rates can hurt/kill your lawn. No need to apply potassium in the summer if your soil levels are ok.


Even SOP? I thought it was MOP that increased salt levels. Is it OK to apply SOP in summer at 1 lb /1000 sq ft or less?

The other issue with SOP is that because it's 0-0-50, it's very difficult to apply small amounts in a spreader. How do you deal with this?


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## g-man (Jun 15, 2017)

Both are salts. One has chloride. https://en.m.wikipedia.org/wiki/Potassium_sulfate

Read the soil remediation guide that point to avoid heavy rates in drought conditions.

I apply it in my spreader without trouble. I even use q greens grade. Weight the amount and use the smallest setting that will flow.


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## Deadlawn (Sep 8, 2020)

g-man said:


> Both are salts. One has chloride. https://en.m.wikipedia.org/wiki/Potassium_sulfate
> 
> Read the soil remediation guide that point to avoid heavy rates in drought conditions.
> 
> I apply it in my spreader without trouble. I even use q greens grade. Weight the amount and use the smallest setting that will flow.


OK, I understood chloride is bad. But sulfur?

What is q greens grade?


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## Virginiagal (Apr 24, 2017)

Neither chloride nor sulfur are bad. Both are essential nutrients. Here's an article on the difference between MOP and SOP. Either can be used for turfgrass. SOP has a lower salt index. When sulfur and potassium are low, SOP can supply both. Chloride is needed in very small amounts. Some crops are sensitive to chloride. Turfgrass is tolerant. I prefer SOP for the lower salt index. But if it's hard to find, I will use MOP. I prefer to not put anything on the grass in the hot summer (90+) except water.
https://nutrien-ekonomics.com/news/potassium-fertilizers-muriate-of-potash-or-sulfate-of-potash/


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## Green (Dec 24, 2017)

For the record, I've had no issues applying Potassium Sulfate in July when it was near 100 degrees for a couple of days. It's one of the safer fertilizers (low salt index). But I applied in the evening when it was cooler and watered it in properly the following morning. Your results may vary, but personally I have no real problem with doing this again if I ever have to. If it was over 100F, I would probably not even walk on the lawn. Also, the purity of your product and what minerals it was derived from can be a variable, too. Potassium Sulfate varies a bit. Currently, there appears to be an issue with ammonium sulfate fertilizer purity in at least some cases.


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