I have been doing my own growing in my back yard for quite a while and found a few thing about growing. If you look at soil all over the earth one thing is pretty apparent and that is the mineral content. Trace minerals are just as important in plant production as basic nutrients in the soil. After many hours of research I have found a few thing about the best ways to grow plants and aquaponics seems to have really made things click for me. My research has found that one inch gravel exactly one foot deep with an auto siphon in a bucket to regulate the natural balance anaerobic bacteria and Aerobic bacteria is what really keeps plants healthy. Most plants need a balance of wet and dry soil periods and the addition of gravel gives the plants much needed minerals. I have seen experiments done with clay pebbles but it doesn't work as well as one inch gravel. I have seen farms that have large ditches that look like rice fields in japan in palm springs so the practice of aquaponics can be done in a mass scale over the land. The biggest problem with using one inch gravel is that it can cause the water for the fish to become too rich creating an imbalance in the fishes eco system. Ideally it is better to have more plants to fish ratio. The science of aquaponics can get very advanced so I leave the research up to the individual but I brought it up because when people often plant they often miss is that the mineral content may be lacking. The best way I have found to grow in soil is a mixture of rock dust wood chips and fungus spores placed over the earth but not in the earth. Wood chips tends to absorb the nitrogen in the soil. so its best to till the soil and plant before you add the wood chips, rock dust and fungus spores. this clicked for me when I was watching a lot of shows on alaska living. I often wondered how they had such amazing plant production and when I realized that the mineral content is high there because of the mountains then it became clear that alaska has good growing because of its mineral content. so no matter how you choose to grow just know that minerals is just as important as adding other soil nutrients like nitrogen. also important is the period of time the plants exist in wet and dry soil. I also think this is why California is such a good growing state because of its rich mineral content. Its really subjective in my opinion to worry about green houses because even in alaska when it alway seems to be relatively cold during the summer months the production is very good. Just food for thought.