Potassium Nitrate - Has anyone used this?
 

After reading Mote's "Florida Orchid Growing Month by Month", I wanted to try Potassium nitrate as an alternate fertilizer.

I searched high and low at big-box stores, garden centers, a farm supply store, and drug stores (it used to be used in curing meats) with no success.

I searched the internet and found that stump removers are frequently Potassium nitrate. Spectracide Stump Remover was specifically recommended. Unfortunately, I found the reference on an amateur fireworks site, not a garden site. They commented that an impure form wouldn't work as well in pyrotechnics, but although I would like explosive growth, an impurity insignificant in explosives might be significant on orchids.

The first garden center I checked did not have the Spectracide brand, but did have a High-Yield Stump Remover. It was a little off-white and was in large granule form that didn't dissolve easily.

I then went to Lowes and found the Spectracide brand. It is a pure white fine powder that dissolves readily in water.

Has anyone used this form of Potassium nitrate? If not I'll try on just one or two before going widespread.

I use Epsom salt & potasium nitrate at the rate of 1 tsp of each/gal. I use it about every 4/6 weeks but especially in fall.

I got a couple of pounds on the internet as a fine white crystalline powder, but I seem to remember it was fairly expensive.

Broward Orchid Supplies carries potasium nitrate. They have it in a couple different sizes including one small size. I used it last year mixed with epson salts. It seemed to do a good job. A speaker at the Fort Lauderdale Orchid Society recently said that nitrate is absorbed by orchids more readily than other forms of nitrogen. I don't know if that's true but my orchids seem to be pretty healthy.

I use it. I follow Dr. Motes's rules on his book, but I use it every two weeks. Doing fine.

Used the potassium as my major fertilizer during the winter per the suggestion of Martin in his monthly emails he sends out, everything doing great with lots of growth so far this spring. I have now switched back to my 15-5-15 as my regular fertilizer but will switch to the potassium and epson salts once a month.

If my memory serves me right, potassium nitrate is the correct name for 'saltpetre' an ingredient in the old black gunpowder.
Fertilizer manufacturers would use in in huge quantities.

Baz

Guess I didn't phrase my question correctly.

No problems or questions about Potassium nitrate itself. I totally trust Motes opinions and recommendations.

Since I couldn't find Potassium nitrate itself, I found reference to Spectracide Stump Remover as being pure Potassium nitrate. The reference was on a rocketry site not a garden site. They felt it was pure Potassium nitrate.

Since it was a rocketry / pyrotechnic site - not a garden site - I am worried about putting something called Stump Remover on orchids.

The question should have been "has anyone used Spectracide Stump Remover as a source of Potassium nitrate.

I have not used or even heard of that. I buy my Potassium Nitrate from Broward Orchid Supplies.

I was hoping to buy local, but may buy from Broward over the net as a second option. I'd rather spend my money on a new orchid than shipping. The Spectracide Stump Remover was only $5 for a pound, so probably a good deal if I can use it, wasted money if I can't.

I read somewhere years ago about using Potassium nitrate or similar oxygen producing chemicals for removing stumps.
Apparently, the idea was to bore lots of holes in the stump and fill the holes with a saturated solution of Pot. nitrate and let it soak into the wood. When dry, the impregnated wood will smoulder away without flames when ignited.
I think you would need to have understanding neighbours who love smoke.

Baz