# DAP 18-46-0 From Home Depot is NOT (That) water soluble



## Mightyquinn (Jan 31, 2017)

Just an FYI for everyone that was thinking of buying this DAP at Home Depot, I just got my shipment and put a pinch of it in about a quart of water and it does NOT dissolve. Now debating on returning it or using it.

**UPDATE**

I just checked it again and with a little agitation and soaking it seemed to help it dissolve a little more, I think it may be possible to spray this stuff with a little pre planning. I might do a full test on it this weekend.


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## Monocot Master (Feb 28, 2021)

Thanks for that info. Have you tried hot or warm water to see if that works better?


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## Bombers (Jul 14, 2020)

Would also like to know the dissolvability of their SOP and urea for those who purchased them, please.


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## Monocot Master (Feb 28, 2021)

@Bombers I have both of those, but are still in the box. Will test soon and report back


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## Mightyquinn (Jan 31, 2017)

Monocot Master said:


> Thanks for that info. Have you tried hot or warm water to see if that works better?


I'm going to run some test on it this weekend, other than it being hard to dissolve it seems pretty clean.


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## Monocot Master (Feb 28, 2021)

Bombers said:


> Would also like to know the dissolvability of their SOP and urea for those who purchased them, please.


I dissolved one tablespoon of the SOP in a jar of lukewarm water from the water hose. I also did the same with the same amount of the urea. I did not shake, just swirled until the granules were gone. The SOP took a minute or so of swirling to be in solution. The urea was much quicker. Maybe 15 seconds. Seems good to me! Maybe longer than other products.? I don't know. But I do know it all dissolved and should not be a problem.


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## Mightyquinn (Jan 31, 2017)

I put 1 lb of fertilizer in a gallon jug with hot water last night and shook it up really good and this morning before leaving for work I checked it and most of it was still there so it doesn't look like it's very soluble to me. I'll check it again when I get home but I'll probably just return it to Home Depot as I don't really use granular fertilizer as the reel mower tends to pick it up.


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## Bombers (Jul 14, 2020)

@Monocot Master @Mightyquinn Thanks gentlemen for being the test guinea pigs.

@Mightyquinn Is that typical of DAP or is it just their formulation?


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## Mightyquinn (Jan 31, 2017)

Bombers said:


> @Monocot Master @Mightyquinn Thanks gentlemen for being the test guinea pigs.
> 
> @Mightyquinn Is that typical of DAP or is it just their formulation?


Honestly I haven't used DAP a whole lot so can't say for sure but I would be highly skeptical of any DAP going forward of its solubility.


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## bernstem (Jan 16, 2018)

DAP is highly soluble in water (~500g/liter at 20C). I have a feeling that the binding agent used to granularize the fertilizer is the problem. DAP without binding agent is a white crystal.


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## Mightyquinn (Jan 31, 2017)

bernstem said:


> DAP is highly soluble in water (~500g/liter at 20C). I have a feeling that the binding agent used to granularize the fertilizer is the problem. DAP without binding agent is a white crystal.


DING DING DING!! I think we have a winner here :lol: This would explain a lot, now to only find it in it's crystal form.


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## bernstem (Jan 16, 2018)

Mightyquinn said:


> bernstem said:
> 
> 
> > DAP is highly soluble in water (~500g/liter at 20C). I have a feeling that the binding agent used to granularize the fertilizer is the problem. DAP without binding agent is a white crystal.
> ...


I have been doing a bit more reading. It seems most Phos compounds are more soluble at low pH. You might add Citric acid to see if that helps.

I am also curious why you want to apply foliar Phos specifically? Most of the reasearch on foliar feeding is with Nitrogen and Posassium. Add in that many soluble Phos compounds are damaging to the leaf and it makes me wonder what the expected benefit will be.


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## Mightyquinn (Jan 31, 2017)

@bernstem My soil test recommends applying Phosphorus and I don't use granular fertilizers due to the fact that I cut my lawn low and any granular will sit on top of the grass and get picked up by the reel. So I am always looking for cost effective spray fertilizers to use on the lawn.


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## bernstem (Jan 16, 2018)

I think foliar Phos is going to be pricy. I assume you have tried SGN 80 greens grade fertilizer (which is also a bit pricy), and water it in before mowing.


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## Mightyquinn (Jan 31, 2017)

I haven't really tried greens grade but I did have some fairway grade SGN 145 (I think) and it was better but still didn't settle very well into the grass. Plus I collect my clippings so who knows how much I would pick up on the next mow even if I watered it in. I have some water soluble 20-20-20 that I'm going to try out and see how that goes. It seems to be the best/cost effective way right now.


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## Monocot Master (Feb 28, 2021)

@Mightyquinn I will be doing the 20-20-20 WS as well. I ordered a $38, 25lb bag from Winfield a couple days ago. It's $61 today! I guess I got lucky and bought just prior to a price increase.


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