Thanks for the response, Sey. I would love to see some reports, any reports, from universities or any qualified source that actually have a specific answer as to how much, in grams, a given tomato plant uptakes for each of the six elemental macronutrients over its life time. My overall goal is to develop a recipe for a potting mix and supplied specific quantities and forms of nutrient fertilizers that consistently result in good, consistent, repeatable yields of tomatoes in the smallest container possible at the lowest cost possible. I have read so many posts by people that get great yields from their container tomato growing efforts, but they all have thrown the issue of cost out the window. When you spend tons of money for Pro Mix Bx potting mix, liquid and granule brand name ferts, mychorrizae fungus, all in 15 to 25 gallon containers for a single plant, of course you are going to get a good yield, generally speaking. There is neither efficient use of science nor great challenge in that. From an economic stand point, that makes no sense to me. I mean, I wouldn't buy a Ferrari for basic transportation to take the kids to school, nor do I need a Gucci watch to tell time. But, if one combines good, objective quantitative and empirically established science with the practicality of sound, common sense economics, I intuit that success is not only quite possible, but quite probable. For container tomato growing, unlike growing in soil, the control of the chemical and physical grow media environment is completely in the hands of the grower The grow media is what the grower makes it. Things like the different migration and leaching properties (or the lack thereof) for each of the nutrients needs to be taken into consideration for determining the grow media potting soil recipe (e.g., quality of air retention, water retention and pass through capacities, electrical properties of the mix to hold onto nutrients [cation exchange capacity], etc.). Another controllable variable is whether to use a Self Watering Container (SWC) approach or a container approach where water is required to drain through the grow media; each of which requires different grow media properties and therefore different mix recipes. The choice of container type also influences the type of fertilizer properties and application since nutrient is allowed to wash through on one container but not in the SWC. Also for consideration are the physical and chemical forms of the nutrient fertilizers; periodic feeding with liquid ferts that contain immediately available macronutrients in dissolved ionic forms, or slow release dry ferts that are either compacted or coated chemicals that retard release over time, and/or macronutrients that are in a chemical form that requires that microbes pass the nutrient through their gut in order to transform the nutrient into the right ionic form that the plant can then uptake. Optimal plant growth and yield are achieved when the plant gets all the nutrients it needs when it needs it. That implies the "right" balance of the "right" grow media and the "right" balance of the "right" nutrients. This balance is, in part, an unstable equilibrium in that an imbalance causes the plant to not perform its best. Too much of one nutrient can crowd out the other nutrient and cause a plant nutrient deficiency in the nutrient that was crowded out. Not putting enough of one or more nutrients will produce a deficiency or deficiencies itself, obviously. There is plenty of sufficient information out there on grow media physics and chemistry. That is not a problem at all. Where there is a great deficiency and gaping insufficiency of information is on the issue of detailed actual uptake of macro nutrients on a per gram per plant basis. And that, my friends, is the all important answer to fertilization, period. It's just not out there; and it should be. I do not buy the response that there are just "too many variables" to deal with. Science deals with much, much more complicated issues than this, every day, all the time, always has, and at a very detailed level. I strongly suspect that the answer is in existence; that there are those that do, in fact, know how much, to the gram, a given cultivar, on the average, under certain specific known circumstances and conditions, uptakes of each macronutrient. Scientifically, it is not a difficult question; it is a simple scientific question, comparatively speaking. I think the answer is not out there "at our level" because we, the tomato growing enthusiasts, haven't asked the precise question yet. We haven't asked each other that question. We, as a group, have all tacitly accepted the approach of "trial and error" much too readily when it comes to fertilizing our plants. When most all people in this forum and all the other forums post how they fertilize their plants, their posts are much, much too general and lack the all important detail with specificity. For example, whenever someone says "I use Tomato-tone when I plant the seedling, then I periodically feed with fish emulsion". That is a near useless post. He/she should indicate exactly how many tablespoons or fluid ounces or cups of Tomato-Tone "per plant" at planting time in exactly how much grow media (if in a container), and exactly how many teaspoons or tablespoons (not capfuls) of what specific brand of fish emulsion and exactly how often it is fed to "each plant"; on a per plant basis. As a result of this information deficit, we have and are spending too much money on growing tomatoes and, in many cases (if not all cases) missing the mark and therefore not getting the results that we should be getting.

i'd like to use crab meal, but can't justify the price. the stuff is super expensive for something that would otherwise be waste and thrown out (supply/demand?). i do know that plants love it. a lot of companies used to use it in their fertilizer blends (such as tomato tone) but have eliminated it from it.. my guess is due to costs.. Alaska fish/kelp pellets is also an excellent fertilizer. i used the stuff 2 years ago and my tomato plants when nuts over it.. plants grew from small 6-8" cuttings to 3+ ft tall in less than a month, but at $7-8 for a small bag it is not economical for a large area. it's great for container gardening. i've also used Jobes organic "water soluble" fertilizer: box image (ingredients). it has kelp and tons of fungi in it too.. not too expensive (about $6) for a box and i would recommend that bundled with some kind of manure,. it beats Miracle grow any day of the week which costs about the same.

You, too, and good luck with your project. I've certainly thought about soil testing, and have always been stymied by not knowing who could do it. And the answer is idiotically simple: go to our local nursery and ask. Instead I'd rather do it the hard way (and it is hard). I never claimed to be a smart gardener. About my soil amending and fertilizing practices: I was much influenced by a book, 'Teaming with Microbes', that was recommended to me by my horticulturalist sister. Basically it talked about the importance of establishing a thriving soil microlife that then nourishes the garden plants. The gardener establishes a virtuous (as opposed to vicious) cycle in which the microlife supplies nutrients to the plants, which grow, die, and the detritus of which feeds the soil microorganisms which recycle the nutrients. Getting the process started is the hard part, in land like ours which is poor in organic matter--hence all the holes and amending--but which, once the cycle gets going well, can pretty much be left to itself. We have so much land to turn into garden that the work is enormous. But I look out my living room window right now at the garden outside (it used to be the farm courtyard), and I think, this works. I don't fertilize my two-story tall 'Jaune Desprez', the substantial shrubs of pittosporum, sarcococca, myrtle, the hardy palms and Tea roses. The bed gets pruning clippings and plant debris, and everything grows fine. Of course we have our clay soil. But if you look at Florida, for example, much of it has very poor sandy soil. And yet jungles grow there. The nutrition isn't coming from the mineral-rich soil, and not from any added fertilizer. It's due to the recycling of nutrients.

"But first, urea is an organic chemical compound, created synthetically from ammonia and CO2 by dehydrating ammonium carbamate under high heat and pressure." True but irrelevant. Your habit of pontificating on irrelevant facts shows that you do not know what is relevant. "It's not a growth regulator (hormone) and doesn't act as a growth regulator" "Growth regulator" and "hormone" are not synonyms. All plant hormones are growth regulators but not vice versa. As far as I know, I am the only one to call urea a growth regulator and this is based on my own experience. But, if you review the literature, you will find many examples of urea having a very different effect than ammonium or nitrate forms for nitrogen, especially when applied as a foliar spray. Also, it is well know and easily verified that urea inhibits the germination of seeds. And, I have heard a rumor, that I can't verify, that a foliar spray of urea forces leaf stomata to open. However, a chemically similar compound, thiourea, has been called a "growth regulator" many times in the literature. If you Google; "plant growth regulator" thiourea , you will get 41,800 results, some that are relevant. "like all forms of N it affects the growth habit of a plant by causing coarse growth - larger leaves and longer internodes." Without changing shape, a larger plant has longer internodes. It is well know that N fertilizers makes plants larger. Shape is the issue. I provided evidence that urea can produce thick stems relative to height in tomato plants, a desirable trait because it requires less staking. You provided no evidence that this isn't true.