View Single Post
  #3   Report Post  
Old 29-04-2008, 02:00 AM posted to rec.gardens
David E. Ross David E. Ross is offline
external usenet poster
 
First recorded activity by GardenBanter: Jul 2006
Posts: 585
Default Combining fertilizers

On 4/28/2008 5:33 AM, Frank wrote:
Frank wrote:
Equal parts of 5-1-1 and 0-10-10 (Alaska Fish and Alaska
Morbloom, great stuff) would yield what NPK figure?


These are weight percentages so you just take the average for 50/50
blend or proportion for any other blend.


Indeed, the numbers represent percentages by weight. If you mix equal
weights of these two, you will get 2.5-5.5-5.5.

That is, if you take 10 lbb of the first, you will have 0.5 lb nitrogen
and 0.1 lb each of phosphorus and potassium. Then, if you take 10 lbb
of the second, you will have 1 lb each of phosphorus and potassium.
Combining them, you will have 20 lbb of fertilizer with 0.5 lb nitrogen
(2.5% of 20 lbb) and 1.1 lbb each of phosphorus and potassium (each 5.5%
of 20 lbb).

--
David E. Ross
Climate: California Mediterranean
Sunset Zone: 21 -- interior Santa Monica Mountains with some ocean
influence (USDA 10a, very close to Sunset Zone 19)
Gardening pages at http://www.rossde.com/garden/