Growing Without Bloom Nutes By Farside05

[farside05]

@InTheShed I was pondering your dilemma and seeking the easiest, cheapest solution. What if you just added a touch of Urea to your Mega Crop? I know Urea is technically its own category, but it works just like Ammonical Nitrogen and drives pH down, therefore I just plugged it in as Ammonical Nitrogen in my spreadsheet. 5g of MC and .3g of Urea looks like this:

MC+Urea.jpg

• farside05
• Sep 22, 2021

A couple pounds of Urea can be had for $10, so its cheap. The MC + Urea seems like a better option than using that 10-10-10 that is missing a lot of Micros. At 28% Ammonical to total Nitrogen, it should be a close match to your water alkalinity. Of course you can always tweak the Urea and Mega Crop amounts a touch to get it exactly where you want. My numbers aren't final, just a jumping off point for the concept.

 

[InTheShed]

Thanks for all that hard work farside! Unfortunately, Premier Tech Horticulture recommends against using urea nitrogen. Here's the quote from an email a few weeks back:

"Urea based fertilizers do not work well for growing media (even not the best for farming). Peat moss, coir and bark, which are the typical base ingredients for growing media, do not have adequate amount of bacteria to convert urea to ammonium form. This is why the majority of water soluble fertilizers do not use urea."

Tomorrow I'll be putting together a post about my recent conversations on pH shift in ProMix, so I'll tag you in there.

 

[farside05]

Thanks for all that hard work farside! Unfortunately, Premier Tech Horticulture recommends against using urea nitrogen. Here's the quote from an email a few weeks back:

"Urea based fertilizers do not work well for growing media (even not the best for farming). Peat moss, coir and bark, which are the typical base ingredients for growing media, do not have adequate amount of bacteria to convert urea to ammonium form. This is why the majority of water soluble fertilizers do not use urea."

Tomorrow I'll be putting together a post about my recent conversations on pH shift in ProMix, so I'll tag you in there.

Thanks for the info on Urea and needing bacteria.

You could go the Ammonium Sulfate route. Also cheap. I just remember you saying something about a Sulfur Overdose with something you were doing. This is 5g MC + .6g Ammonium Sulfate.

MC+Ammonium Sulfate.jpg

• farside05
• Sep 22, 2021

 

[InTheShed]

Do we know if peat can break down ammonium sulfate? And are you using 21ppm NH4 and 24ppm S for your calculations?

 

[farside05]

Do we know if peat can break down ammonium sulfate? And are you using 21ppm NH4 and 24ppm S for your calculations?

It's a salt, so it should be available. Reference

Yes, those are the numbers I used.

 

[InTheShed]

Great article, thanks! And much of my conversation with the PT guy centered around this from your link:
"In the end the nitrate/ammonium ratio is perhaps one of the biggest weapons you have in controlling how your plants change the pH of your nutrient solution."

For me, continuing to use ProMix would involve constantly balancing that ratio (with either more NH4 or sulfuric acid), since it changes depending on the PPM of each N type at the various feeding levels along with the alkaline content of my water.

 

[farside05]

Great article, thanks! And much of my conversation with the PT guy centered around this from your link:
"In the end the nitrate/ammonium ratio is perhaps one of the biggest weapons you have in controlling how your plants change the pH of your nutrient solution."

For me, continuing to use ProMix would involve constantly balancing that ratio (with either more NH4 or sulfuric acid), since it changes depending on the PPM of each N type at the various feeding levels along with the alkaline content of my water.

Per Blackmore's article, around 25% Ammonical to Nitrate should be optimal for water with an alkalinity of 75-150. That should eliminate the drift you are seeing in theory. Now if you could make a concentrated liquid from your powders that you could dose per ml/gal for different growth stages, that would be ideal rather than measuring tiny bits of powder. Of course my attempts of making concentrates from MC never worked out well.

 

[InTheShed]

Is that the 4.2% NH4 to 12.8% NH3 on his chart? When I asked the PT guy he said those ratios would vary depending on the PPM of total N.

He gave this as an example for 200ppm CaCO3:

"Look at the potential basicity or acidity of the fertilizer. With alkalinity of 200 ppm, a fertilizer with a potential acidity of 350-450 CaCO3 equivalent would work well for an all around fertilizer applied at 100 ppm of nitrogen.

"As the rate of N increases for an ammoniacal nitrogen fertilizer, the more potential acidity you are putting on….vice versa for a nitrate nitrogen fertilizer….more potential basicity to raise media pH for NO3 fertilizer. I used 100 ppm of N as an example. There are fertilizer calculators on line that you can use to calculate what fertilizer blend will work for you."

And he gave me a link to a alkalinity calculator on UNH's website (that seems not to be working at the moment). I did mention to him that other than Jack's, most nutes don't list their potential acidity.

He didn't think this was going to be a one-blend-fits-all situation.

 

[FelipeBlu]

Do we know if peat can break down ammonium sulfate?

No microbes needed in this case. The ammonium cation is directly taken up by the plant, which releases H+, which brings down the substrate pH.

 

[InTheShed]

No microbes needed in this case. The ammonium cation is directly taken up by the plant, which releases H+, which brings down the substrate pH.

Thanks Felipe! And the ammonium cation is in the form of nitrogen? We don't think of our plants as taking up ammonium!

 

[FelipeBlu]

Yep, the cation is NH4+

 

[InTheShed]

Thanks! I do not have a grasp of vacations and oanions.

 

[FelipeBlu]

If your soil has nitrifying bacteria (which PM doesn’t), the ammonium can be converted to nitrate.

 

[InTheShed]

If your soil has nitrifying bacteria (which PM doesn’t), the ammonium can be converted to nitrate.

Interesting! Peat becomes an advantage here.

You do know your geology.

 

[FelipeBlu]

Chemistry too - and it almost got me in trouble/dead a few times!

The reason the substrate pH goes up when you are using a nitrate fertilizer is because the plant releases OH- when it takes in NO3-

 

[InTheShed]

That I do understand! I needed to in order to wreak havoc with my thread:

Do we need to pH adjust our nutrient solutions?

Greetings all! I recently had a running email conversation with the "Grower Services & Product Development Director" at ProMix (aka Premier Tech). I began the conversation by posting a question on their website, asking if I should be treating ProMix HP as soil or soil-less when mixing...

www.420magazine.com

 

[FelipeBlu]

Indeed!

 

[InTheShed]

Thanks for the info on Urea and needing bacteria.

You could go the Ammonium Sulfate route. Also cheap. I just remember you saying something about a Sulfur Overdose with something you were doing. This is 5g MC + .6g Ammonium Sulfate.

MC+Ammonium Sulfate.jpg

• farside05
• Sep 22, 2021

I ran those numbers through hydrobuddy and came out almost the same as yours , but my (@MrSauga's) target for S is 10% of N, or ~15ppm. 63ppm blows that away!

 

[FelipeBlu]

Do you have his source handy? I don’t think I have had any problems at 65-80ppm S. I think it’s an important component of flavor.

 

[InTheShed]

Do you have his source handy? I don’t think I have had any problems at 65-80ppm S. I think it’s an important component of flavor.

I don't (not that I can find quickly anyway), but when he has a chance he might stop by with that info.

I'll keep looking though...

[edit: does this help?]

[edit #2: I may have no trouble at all with higher ppm of S and all my troubles might be related rising pH.]