Sorry to be bugging everyone about a protocol that I think most seem to have mastered. I have yet to attempt it, but have some valuable seeds I would like to try to resuscitate and germinate after more than a year in the fridge… Like, as in, two years…
Having called and confirmed they stock such a few days before, I traveled to a regional hydroponics store only to find they had sold out of the 1 lb bag of Ca(NO3)2. The clerk suggested I consider another product derived from bat guano, calcium nitrate, and Magnesium nitrate – a much smaller amount at 8 fl oz, but not that much more expensive than a 1 lb bag, which I would imagine would last me a lifetime. (In retrospect, I wonder if I should have confirmed fruit-eating or insectivorous bats, but I imagine that is a trivial part of the makeup.)
The analyses of this 8-0-0 Nitrogen supplement is:
Total (N)------------- 8.0%
of which Nitrate N is 7.5%, and remaining .5% other water soluble forms (ammonia?)
Total Ca-------------- 8.0%
Total Mg-------------- 0.5%
So… And I’m gonna hurt myself here… 10 mM is a 10 to the -2 molar solution, correct? (10 x 10^-3)
Nitrate has a molar mass of about 62 g/mol…
<sound of gears grinding, or crickets chirping, or wind whistling…>
…Ummm Okay, I think I pulled a muscle in my brain. Apparently I really have forgotten how to do this sort of conversion…
I don’t think it matters, but the solution I have is 250g and 235ml.
Could somebody out there throw me a bone, and help with my math??
For that matter, I have done a lousy job of archiving my newsletters… Is there a link to the full protocol on this forum?
BTW, I assume it is easier to calculate going metric, which is fine by me. I certainly won’t be needing more than a liter of the stuff in view of my paltry harvest.
The guano is more likely urea or uric acid. Land animals don’t excrete ammonium, only fishes do.
No one has tested that combination but it probably works. The 10 mM is the calcium by convention. So actually it is 20 mM in nitrate. A mmol is 1/1000 of a mol. A mol is the substance times its molecular weight, which for N is 14. for nitrate it is 14 + 48 ( three oxygens). So 62 x 20= 1240 mg/L. Times 0.85 = the amount needed per quart (1085 mg, about 1 gram). To account for the calcium you need to add some. 10 mM x 40 = 400 mg, per L. Add 0.85 of that to the 1085 above and you end up with about 1.4 grams per qt.
Looking at the % N as nitrate you have 7.5 g/100 g or 75 mg/g of the mixture, about 7.5 mmol of N per g mixture. if you want 20 mmol/L of N you need around 3 g/L. Time 0.85 is around 2.5 g/qt. That is about 1/2 to 2/3 teaspoon per quart, depending how densely you pack into the measure.
I would make a gallon of solution with 10 grams of your mix. A kitchen scale can read 10 grams close enough. Use any leftover solution as fertilizer for any plant that wants some nitrogen. This is about the same concentration as straight Hoagland’s solution which is fine for watering most houseplants. Or you can always put it in the garden.
Thank you, Larry!
Admittedly, I got lost a little bit with your numbers, but you did jump start a few of the old neurons. (I didn’t, however, grasp the accounting for the Ca in the math.)
I tried calculating this again and I got close to the same solution:
Striving for:
10 mM Ca(NO3)2 = 20 mM NO3
20 mM x 62g/L [molar weight of NO3]= 1240 mg/L of NO3 (the dilution rate to be achieved)
Beginning with the existing solution of “7.5% Nitrate Nitrogen”, or 75g/kg…
[This is where I think I was initially messing up as I was calculating based on weight of nitrate, and not nitrogen which would imply a much higher concentration.]
1 Mol of N is 14g/L.
The solution weighs 250 g, and contains 235 ml. Doing the conversion to liters, the existing solution of 7.5% is then:
[1kg x 235ml/.250kg = .940L] thus 75 g/940 ml, or approx. 80g/L of Nitrogen. This would equate to about 354 g/L of NO3, (having a higher molecular weight of 62:14)
If I’ve done math correctly, and made appropriate assumptions thus far (??!) then to dilute a 354g/L solution to a 1.24g/L solution, I would do approx. a 1:285 dilution. THat’s roughly 3 1/2 ml/liter. Ultimately, my 8 fl. oz bottle will be good for about 67 liters of finished solution. (I suspect the bat guano will have gone funky long before I use that up!)
I apologize for beating this thing to death, but I don’t want to mess this up. I was worried that I might do better to wait for the store to restock, repeat my trip, and exchange this stuff for pure Ca(NO3)2 to avoid the hazards associated with my poor math, but I find consolation in the fact that you and I have now come up with comparable rates of dilution…
I don’t know why I assumed ammonia for bat poo. (I think I remembered seeing a show in which some cave explorers were complaining about fumes coming off a pile of the stuff, but I doubt spelunkers took the time to analyze the more nuanced aromas coming from a pile of bat scat.) I’m thinking urea might be less toxic to seedlings?
BTW, I unfortunately won’t be able to provide any meaningful feedback on success of this solution as 1) seeds are very old and may lack viability, 2) the limited quantity of any cultivar is statistically meaningless, and 3) I will have no control whereby I could compare results, but for anyone who cares, the solution is here: http://www.aurorainnovations.org/grow-n.html
This page does not show the 8 oz size I purchased, and other sizes can be found at 2/3 price advertised here at Aurora’s site. (Shipping for qt size from other vendors would bring total back up to close to MSRP in above link.)
I was doing the calculation for assuming you were working with solid when I threw in the calcium. The calcium nitrate that I get is a crystalline form with 7 mol water for each , so it is a solid but very wet. It you have a solution you do best to work from the stated N content and focus on that. If you have 7 %, you have 7 grams in 100 mL or 70 g in a liter. You need 20 x 14 mg/ L or 280 mg/L. So a simple 250 x dilution is what you need.
The guano would smell of ammonia in a cave because there are enzymes in some bacteria living in there and they are breaking down the guano, releasing ammonia. Just like an unflushed urinal contains Clostridium acidi-urici living off excreted urea/uric acid and releasing ammonia.
Thanks, Larry! Apologies for any confusion I caused in my description. I think I heard that ammonia can be toxic to seedlings, so I’m glad to hear that it isn’t that!
I don’t know if anybody is shopping for NO3, but at Walmart, I saw that Alaska naturals (the folks who sell the fish emulsion) has a new line that includes a Calcium Nitrogen Magnesium solution, of calcium nitrate and magnesium nitrate (N 3.00%, Ca 3.00%, Mg 1.00%) in a quart for less than $10.
If my conversion is accurate, that would be a 1:100 dilution rate, so 25 gallons of finished solution.
No idea if Mg has any effect on seedling as compared to Ca, but I would assume it wouldn’t harm, even at this early stage.
Just thought this might be more readily obtainable to pretty much any- and everyone since Wally World is everywhere, alas. (Just don’t buy their rmv roses!)
By my arithmetic, if the analysis is as posted on the label you have about 2.15 moles nitrate per liter, about 0.75 moles of calcium and 0.4 moles magnesium. A 1/100 dilution would give 21 mmol nitrate with about 11 mmol of the Ca + Mg. So a final volume of 26 gallons would be exactly right. 1/100 is close enough for this kind of work. This weighs all together over 200 lb, enough to moisten 100 lb of vermiculite, maybe ten large sacks. Really a cheap deal.
The extras would make a great fertilizer solution for roses, thought I would dilute it even further if using it more than 2x per season. Not as cheap as urea, but less likely to burn.
The paper that Henry cited is interesting. Back when I first began testing effects of salts I tried quite a few, even a few combinations. I was actually expecting calcium to be the important ion, not nitrate. But calcium chloride or magnesium chloride or sulfate was not beneficial. Magnesium nitrate was about as good as the calcium salt I think, but not easy to buy at a regular store. Later I tested a calcium (with a little) ammonium mix which worked fine. That was very cheap in big bags for some purpose like hydroponics.
Thanks, Larry. A quick online search seems to indicate that Lowe’s and Home Depot might also be carrying that line in my area. Dunno why, but I’m in Austin, and I wouldn’t be surprised if we have an above average rate of home hydroponic growers. I don’t know if such is so readily available elsewhere.
I just realized that it has more Mg than the solution with bat guano I already purchased, so as long as I have plenty of the other, I won’t do any experimenting…