http://www.hbci.com/~wenonah/min-def/tomatoes.htm
I've probably linked this helpful page before, but I'll do it again. Despite being "old science" from the 1940's, the information is helpful in diagnosing what's wrong with a plant. I'm presuming how these experiments were done were that the plants were grown in a non-nutritive culture (sand, it says) and were fed fertilizers that omitted one of the required nutrients. Eventually the plant developed the deficiency-- the result is shown (N deficient, P deficient, K deficient, etc).
I'm using Miracle-Gro at home, and let me tell you, the stuff really works well. My tomatoes are lush, green, flowering, and about 3 feet tall-- twice as big as the tomatoes planted in the same soil mix at NKU. We don't use Miracle-Gro at NKU, and that's fine, because it's an Organic Garden. It's important to stress that Miracle -Gro by itself isn't perfect. My dad showed me rudimentary gardening when I was a kid-- basically, put a plant in the ground, and apply Miracle Gro when you remember to do it. The soil was pitiful-- weeds wouldn't even grow in it. Miracle Gro helped a bit to produce some undersized tomatoes on scraggly plants, but not much. They looked like some of the plants in the previous links.
I think the path that I will continue to take as I create my own gardens will be a hybrid of organic and conventional methods. I like growing in "Mel's Mix" medium-- compost/manure, peat, and vermiculite. It's a richly organic mix-- 30-40% organic matter, compared to native soils being less that 5% organic matter. I will continue using this soil mix for the forseeable future.
In addition, I like using Espoma Plant Tone-- it's such a rich, diverse mixture of organics from a dozen different sources. I like adding some extra bone meal too-- because not only is it high in Phosphorous, it's also high in Calcium-- which miracle gro lacks, if you read the label. If I've got some free coffee grounds in bulk quantities (enough to spread about 1/4 cup per square foot) , I'm a fan of that too. And finally epsom salts-- magnesium sulfate-- providing magnesium and sulfur-- i use 2 tablespoons to a gallon of water, once per month.
Ok, so I tinker! I seek optimal growth from the garden.
The comparative observations that I've made about the NKU gardens, compared to mine, is that by harvest, there's signs of acute nutrient deficiency, particularly N. When fruit production happens, this is presumably when plants are consuming the biggest quantities of nutrients .Organics are very slow release. Boosting the nutrition with miracle-gro seems to cure this.
I'm by no means suggesting we abandon the founding organic principles of the NKU gardens. I'm just saying I'm not a purist.