# 20-20-20 water soluble fertilizer for lawns



## Awar (Feb 25, 2019)

I used 20-20-20 water soluble fertilizer with my PGR & iron applications the last 2 seasons. I'm wondering if I should invest in another 25 lbs bag of the same this season. I honestly can't tell how much this contributed to my lawn, but overall I'm happy with my results...

My soil is deficient in P & K so I apply granular N,P,K once a month but supplement with liquid 20-20-20 every ~2 weeks. My soil's Cation Exchange Capacity (CEC) is very low so the soil does not hold nutrients well, which is why I think supplementing with 20-20-20 as foliar feed is probably a good idea.

Any thoughts on continuing with this plan?


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## Mightyquinn (Jan 31, 2017)

I think as long as you get an annual soil test to make sure you still need the nutrients you are fine.


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## Awar (Feb 25, 2019)

Mightyquinn said:


> I think as long as you get an annual soil test to make sure you still need the nutrients you are fine.


Yes I will definitely be getting annual soil tests. P & K levels are so low that it's hard to get them back within range early in the season (need too much poundage) so I hope the bi-weekly 20-20-20 foliar apps help.

What would be the recommended rate per 1000 sq-ft for 20-20-20 foliar app on bermuda assuming I do it every 2 weeks? If I want to apply say 0.1 lbs of N-P-K per 1000 I'll need 0.5 lbs (8 dry oz) of 20-20-20 per 1000. Is that too much? I've been doing 5 dry oz per 1000 which gives approx 0.06 lbs of N-P-K per 1000 but I can bump it up if appropriate.


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## Mightyquinn (Jan 31, 2017)

I've sprayed 20-20-20 at 1 lb/M (.2 NPK) without much issue. You could technically spray it at a heavier rate but you would want to use more carrier(water) and/or water it in immediately after you spray and it will be a soil application and absorbed by the roots. Are you opposed to using granular at all?


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## Awar (Feb 25, 2019)

Mightyquinn said:


> I've sprayed 20-20-20 at 1 lb/M (.2 NPK) without much issue. You could technically spray it at a heavier rate but you would want to use more carrier(water) and/or water it in immediately after you spray and it will be a soil application and absorbed by the roots. Are you opposed to using granular at all?


I apply granular once every 4-6 weeks. I don't have this year's soil test and my fertilizer plan in front of me now, but this includes P & K based on the soil test results and the recommendations from this thread: https://thelawnforum.com/viewtopic.php?f=24&t=1088

Last year I discovered the P & K deficiency, and the input I got from @Ridgerunner is that based on my low CEC, my soil does not do a good job holding nutrients. So just dumping 5 to 6 lbs of P & K per 1000 per season might not be as effective. I thought supplementing with 20-20-20 (instead of 46-0-0) when I do my bi-weekly PGR apps would be a good way to give my bermuda the P & K it probably isn't getting from the soil! Here's my soil test thread from last year: https://thelawnforum.com/viewtopic.php?f=24&t=19014


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## Mightyquinn (Jan 31, 2017)

What granular are you using?

Do you prefer spraying or granular?

Phosphorus tends to bind to the soil better than the other 2 so you might see some improvement there but you will probably be adding Potassium for the foreseeable future as that gets used up almost as fast as Nitrogen does especially if you collect your clippings. I'm in the same boat with Potassium and add 1 lb/M a month with Potassium Sulfate(13-0-46)


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## Awar (Feb 25, 2019)

Mightyquinn said:


> What granular are you using?
> 
> Do you prefer spraying or granular?
> 
> Phosphorus tends to bind to the soil better than the other 2 so you might see some improvement there but you will probably be adding Potassium for the foreseeable future as that gets used up almost as fast as Nitrogen does especially if you collect your clippings. I'm in the same boat with Potassium and add 1 lb/M a month with Potassium Sulfate(13-0-46)


I like granular as it's easier/quicker to spread than spray, but I have to spray PGR every ~2 weeks and of course sometimes spray fungicide, so I can add liquid fert and/or iron to my apps easily.

This year I used Groundwork 18-24-6 starter fertilizer from Tractor Supply for the extra "P" (link: https://www.tractorsupply.com/tsc/product/groundwork-starter-18-24-6?cm_vc=-10005), and I'm using Easy Peasy Muriate of Potash 0-0-60 from Amazon for the extra "K" (link: https://www.amazon.com/gp/product/B076GNM23L/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1). I don't like the Tractor Supply product as it was damp and clumped so it gave me a hard time to spread it, and then even after watering a couple of times the white granules stay on top of the grass and I can see/hear my reel hitting them when mowing a couple of days after the app.


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## Mightyquinn (Jan 31, 2017)

Awar said:


> *granules stay on top of the grass and I can see/hear my reel hitting them when mowing a couple of days after the app.*


This is why I went to spraying everything as the more you reel mow the more this becomes an issue. I think the plan you are on is fine and you should see some improvement but don't expect miracles and you can always tweak it as you go to make it more efficient, that's what I'm always doing. I would just focus on getting the Phosphorus numbers up and then you can just focus on the N & K :thumbup:


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## Awar (Feb 25, 2019)

Mightyquinn said:


> Awar said:
> 
> 
> > *granules stay on top of the grass and I can see/hear my reel hitting them when mowing a couple of days after the app.*
> ...


Thanks, I appreciate your input :thumbup:


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## kem5882 (Apr 30, 2020)

Question...how much 20-20-20 can you mix per gallon of water?

I believe I've read 2-4 gallons of water for each pound. Wondering if I could do more than that as long as I water it in right away? I have a 4 gallon backpack sprayer and it would take forever if I'm only doing 2lbs per 4gallons for my 8k SQ ft lawn.

TIA!!


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