# Slow release fertilizer, how much to apply?



## Saint Louisan (Jul 31, 2019)

So I got myself some 50% slow release 22-0-5 and don't know how to use it..?

I've read something from UNC I think that said 1lb N per ksq, my local botanical society recommends 1/2 lb, I've been using 3/4lb N per 1ksq, seems to work fine.

But how much should I use now that I'm using slow release? I feel like it would require more but what do I know!

Those in the know, enlighten me at you leisure


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## Mightyquinn (Jan 31, 2017)

You can use the same amount and theoretically you shouldn't have to apply it as often. You should get 4-6 weeks of feeding from that fertilizer depending on weather and soil conditions.


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## twolf (Jan 25, 2019)

Let's think about it this way:
If you throw 1 lb on N in a form of Urea, the turf receives huge hike of N, which is mostly gone in 2 weeks. If half of this urea was coated (that is it is slow-release N), then the initial hike is lower, and due to slow release the effect is prolonged.

With fast-release N (e.g. uncoated urea) you might be better off throwing 1/2 lb every 2 weeks. With 50% slow release fertilizer you can throw 1 lb every 4 weeks with roughly the same effect.

Here is good read on this topic
https://www.gcsaa.org/uploadedfiles/Education/Conference-Sessions/2014/Nitrogen-Sources--The-Form-That-Fits.pdf


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## corneliani (Apr 2, 2019)

Since not all SRN has the same release curve one way to look at how much to put down is in reverse: how much fast-release N does that fert put down, and what's the max that you're comfortable with? For a 50% slow-release fert that may be 3/4#N in fast-release, translating to 1.5#N. That's assuming the SRN technology used on those prills won't release earlier than claimed. At that point maybe that 1#N rate is the sweet spot. Which begs the question - does your type of zoysia really need 4#N yearly? I shoot for closer to 2# on the Emerald zoysia at my folks' place. 4# is asking for major thatch/fungus problems in my climate.


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## Saint Louisan (Jul 31, 2019)

corneliani said:


> Since not all SRN has the same release curve one way to look at how much to put down is in reverse: how much fast-release N does that fert put down, and what's the max that you're comfortable with? For a 50% slow-release fert that may be 3/4#N in fast-release, translating to 1.5#N. That's assuming the SRN technology used on those prills won't release earlier than claimed. At that point maybe that 1#N rate is the sweet spot. Which begs the question - does your type of zoysia really need 4#N yearly? I shoot for closer to 2# on the Emerald zoysia at my folks' place. 4# is asking for major thatch/fungus problems in my climate.


Like I explained in the op the local botanical society recommends 1/2lb per k another says 1lb. I've been using 3/4lb. At that rate I believe I'm using less than when I was applying at bag rate from the home center.

I bought this property 5-6 yrs ago and at that time the thatch was within acceptable range. I started getting serious with the lawn 3yrs ago and have power raked it this and last season (sunjoe). The thatch hasn't increased

It's durable grass

I appreciate all the replies, thanks to all!


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