Posted: 19/07/2012 at 23:58
As the others have said all fertiliser has NPK. In bought fertiliser it usually shows the ratio of each. Depending on what you're growing/time of year/make up of your soil will determine which type you need. If you garden organically then you wouldn't want to be using artifical fertilisers. However, fertilisers such as Bonemeal, Blood,fish and Bone, seaweed, poultry manure are classed as organic. They'll have a different NPK ratio depending on the type. They also break down at different rates. I use a slow release fertiliser, such as bonemeal, which is rich in N (Nitrogen), when I'm planting up. Liquid Seaweed is good to give plants a quick boost, especially plants in pots. I also use part of my nettle patches to make liquid fertiliser as it's rich in N. Stinks a bit though, so don't do what I did one year and "cooked" it too near my back windows. The neighbours weren't too happy either 
