I've used organic fertilizers and would certainly recommend their general use, but I, like many growers am constrained by certain uncontrollable circumstances. Such circumstances lead me to the application of salts and chemical fertilizers. I figure this thread would allow me to condense all my info into one place as an easy reference myself. But I realized it could also be a great tool for other growers who are already proficient in salt ferts or want to get better acquainted with them.
Let me just say that learning this aspect of growing can make the difference between good bud and AWESOME herb!!! Whether you whip up your own complete fert mixes or just supplement your organics with Epsom salts, I hope this thread may be of use!! If only a few people benefit from this, it was worthwhile!
From the get go, I want to STRESS that this post is not an attempt to place salts or chemicals upon the throne of all fertilizers! Circumstance, cost, and conditions always apply.
If you have a nice plot of land and not too worried about intrusion, organics may be the way to go. However, if you are inside, going for quick crop rotation or using containers, I believe salt ferts to be the best choice.
There are premixed commercial ferts, but the GOOD ones (usually liquid) made specifically for "hydroponics" are very expensive. The powdered ones are cheap, but they're.....well, cheap. They have poor balance, little if any of many micronutes, and you usually end of buying 3 different ones for various stages of growth.
With salt ferts, you can exercise more precise control over the concentration and balance of your nutrients. Another benefit is cost; a 5 pound bag of TripleSuperPhosphate costs about $5 and will last YEARS Another benefit of salt/chemical ferts is that they lessen vulnerability to insects and pests.
The drawbacks? Mainly, volatility. If you're the type to drop some seeds, set a timer, and check once a week, I wouldn't recommend this system of fertilization. Salts, as if I need to point this out, have a very high salt content. If you overfertilize, you will toxify the soil quickly. Many salts also have the potential to dramatically sway pH. Bottom line, if you use the salts, you should get a pH tester until someday it becomes natural. A PPM meter is also recommended.
Click on the appropriate link:
pH...The 'Qi' of Fertilization
Salts, E.C. and Leeching
TDS, PPM, EC
Basic Elements & Nutrient Balance
Fertilizer mix examples