A good choice
Thumbs.
If you look at it on a basic N-P-K level..
Nitrogen -
Poultry, sheep and cow manure are a good source of Nitrogen and have excellent water retention as a bonus. A lot of the Nitrogen in manure is in Ammonia form so be careful not to over feed as too much Ammonia Nitrogen will cause stretchy plants with weak immune systems. Worm castings are also a source of Nitrogen and although having only small quantities of Nitrogen they are packed to the brim with useful micro nutrients that your plant will love you for! Some use blood meal as a source of Nitrogen but I personally don't like it as it can attract pests and the occasional hungry predator to your grow site (particularly outdoors doh!).
Phosphorous - I tend to use
bat guano as a source of Phosphorous, follow the labelling for directions as to the amount as it is easy to overdo and will drop your soil pH noticeably. Many use bone meal for Phosphorous but for the same reason I don't use much blood meal I generally stay clear.
Potassium - Organic sources of K include
muriate of Potash,
Kelp meal and
wood ash. Be careful with wood ash as it has very high alkalinity and also with all three (but particularly the kelp) be aware that they have a fair bit of Calcium in them which is needed for strong root growth but can easily be over done.
Further Nutes - I also use a little dolomite (horticultural) lime in my soil mix to balance pH (get some of your soil mix in distilled water, let it sit for an hour and check with a ph meter or strip) and also to add a little Magnesium. This too adds Calcium to the soil though so you must always be aware of not just each part of your mix but also the overall picture.
Anyway, take it easy man.
SS