When I was lambing, back when I was but a nipper of a proto-vet, the farmer said to me that he didn’t farm sheep, grass was his crop. No, this wasn’t an admission of illicit herb horticulture, but recognition that he grew grass, and then the sheep ate the grass, turning grass into meat. He then sold the sheep. It was an interesting perspective on what his crop actually was.
Unless you have an equally unhealthy interest in plant growing, you may be unaware that actually a lot of thought and consideration goes into the choice of fertiliser. Fertilisers contain three main elements of interest; nitrogen, potassium and phosphorus. Nitrogen for leaf growth, potassium for fruit growth and phosphorous for root growth. So in theory, your tomatoes get a high potash (potassium) feed, brassicas a high nitrogen feed, and potatoes a phosphorous-rich feed. And that’s all grand and good, and we can boost the levels of these elements in the soil if we like, but fundamentally plants are mostly (something like 90% of their activity?) just photosynthesising – they are using sunlight to turn air (specifically the carbon dioxide bit) into more plant.
Which basically makes us GYOers farmers of air and sunlight. Which is rather nifty.