NPK fertilizer - How to formulate your own

[Orchid126]

An article in our local paper was about Kate Clapp who was the Beacon Journal's garden writer for 42 years, retiring in 1976. She had her own formula for fertilizer which is as follows:

Combine 1 gallon water, 1 tablespoon ammonia, 1 tablespoon saltpeter, 1 teaspoon baking powder and 1 teaspoon Epsom salts. Can be diluted with a bit more water if desired. (saltpeter and Epsom salts can be found in drugstores).

The article does not give the NPK ratio of this fertilizer, nor does it explain the role of saltpeter or baking powder, but the formula is still being requested after all these years, so it must do something.

[PaphMadMan]

Household ammonia is a relatively dilute solution of ammonium hydroxide, and supplies nitrogen in ammonium form. Saltpeter is potassium nitrate, a significant part of most water soluble fertilizers, and obviously provides potassium, and nitrogen as nitrate. Epsom salts supplies magnesium and sulfur. They all supply necessary nutrients without adding anything that plants don't need.

Depending on the specific formulation baking powder may supply potassium, phosphorous, calcium and sulfur, and probably helps adjust the pH of the solution, but it also contains a lot of sodium, carbonate and often aluminum. Personally I wouldn't use it on any plant I valued. If you started with distilled water this essentially makes it more like hard water that has been through a water softener.

Without knowing the formulation of baking powder used it isn't possible to determine the N-P-K rating, but it could be almost or completely lacking in phosphorus. It probably has an overall mineral content similar to full strength water soluble fertilizer, or higher.

Even the cheapest water soluble fertilier would be safer and more reliable for your orchids than this formula.

[glengary54]

This is a formula one of my commercial grower friends uses on his personal plants:

1 tsp baking soda
1 tbsp Epsom salts
1 tbsp Potassium Nitrate
1/4 tsp ammonia
1 gallon water
Add 5 tbsp brewed black coffee for acid loving plants (ie,encyclias)

[stefpix]

is it worth? for 4 dollars you can buy Better Gro orchid fertilizer with no Urea that can last you a year or so. In one single container and only one trip to one store and one cash register.

you could also urinate in a bucket and add 10 times as much water.

[stefpix]

Also you can buy Osmocote, Nutricote etc at places like Target in September with slashed prices with 75 % off or something like that. Gardening season is over for many and all the stuff is at rock bottom prices. just stock up.

[Ray]

I can only see making one's own formulations if decent commercial formulas are not readily available or you have too much time on your hands and it's a "neat thing" to do.

Most powdered fertilizers, when diluted to a reasonable level (100-150 ppm N) only cost a few cents per gallon to use.

[orchids3]

I actually looked into formulating my own fertilizer and gave it up after starting to collect ingredients. Most of it came in 50 # bags and a lot of it absorbs moisture which dictated that it had to be stored in a cool dry place. Some is caustic. It seemed more practical to just buy ready made fertilizer. Ingredients when bought in small quantities are expensive because a lot of the cost is packaging. When bought in large quantities - well thats a lot of fertilizer and would take me the rest of my life to use even if I can successfully store it. Its all a matter of being practical.