I just finished reading the thread about signs of over fertilizing and saw some very informed answers and started thinking about my garden and am looking for some input, but didn't want to hog the other thread.
I garden in glacier slurry, which is non-soil. My house pad and gardening area were cut out of a slope. I've gone about creating the rose garden all wrong, but that's not the issue I want to address here.
When I bought my house in '04, the soil was dead. It was covered with weed barrier and decorative rock. Since I could not afford to have all of the yard escavated and new soil brought in, I ended up digging holes in the glacier slurry to plant the roses. I screen out all of the rocks and added lots of compost to the natural soil and planted the roses. In the first years, I used organics to feed the plants, mulched twice a year and watched the plants kind of limp along.
It finally dawned on me that the garden level is four feet down from where the natural top of the soil where plant debris from nature would have fed the soil. In other words, it was highly unlikely that there was any organic plant material in the soil, other than what I had added.
I've been told it takes at least 10 years to build up soil to where it can provide nutrients to plants. Last year, I tried a chemical fertilizer, and the garden looked completely different. The plants were no longer limping along, but were actually thriving.
We get on average 40" of rain each year, with hot dry summers. Drainage in glacier slurry is not a problem as it is very porous. .. no puddles no matter how hard or long it rains.
How would you go about fertilizing plants in non-soil ? And what strength of fertilizer should I use ?