13-0-46 is potassium nitrate. In the greenhouse grade its diluted in water and injected through drip lines to plants from a fertilizer injector the same for urea and the others you mention. If its less refined the 13-0-46 is used in mixing potting soil along with phosphate. If you want to be head grower you should already know this stuff... Bob.

Having been associated with a large wholesale growing operation myself, I can safely say that chemicals/fertilizers tend to accumulate over time and their applicability to any specific growing situations may or may not be present :-) IOW, stuff gets bought from eager sales reps cuz the price is irresistible or it's tossed in as part of another deal and there may very well be NO practical use for it. Just cuz it's there doesn't necessarily mean it HAS to be used.....or that it should be used.

The 20-20-20 and the 19-19-19 are balanced, all-purpose fertilizers and can be used for any plant/purpose. And no, there is NO significant measurable difference between the two. The urea has me a bit perplexed......it is heavy-duty, straight nitrogen and generally most appropriate in an intensive agricultural cropping situation. Unless there are some other growing activities going on not disclosed, I can't imagine ever needing more than a bag or so of this, let alone an entire pallet.

The other fertilizers mentioned will all address some specific need for a nutrient in dosages other than the balanced formulations would provide. Sulfur/sulfate is an acidifier and is used as a fungicide as well. Phosphorus promotes flowering and is often the primary nutrient for a lot of commercial water garden ferts. And minor elements are often used to supplement other ferts that tend to be lacking in these trace minerals.

Have you inquired of others (like the current head grower, owner, buyer, etc.) what all these products are used for, if at all? Depending on the materials grown for the green roofs, I can't imagine a lot of this stuff is used very much or very often. The water plants sure don't need much of it.

And Bob, I found your response just a tad snarky :-) Often in smaller growing operations, one works their way up to a position of more responsibility by virtue of work habits, leadership/management skills, dedication to the job etc., but without benefit of formal training. And understanding fertilizers is a complicated subject - lots of folks don't have a clue why they use what when. That the OP has even taken the time to inventory the stuff and ask about it says a lot. Heck, the guy speaks English -- that's enough to get him promoted at a lot of places just in itself!!

When I was in college, one of our primary texts was the Western Fertilizer Handbook, published by the California Fertilizer Association. It was a very basic yet thorough presentation of plant nutrient requirements, fertilizer methodology and how plants access and metabolize their required nutrients. I'm not sure how specific a text like this would be to west coast growing only (I can't imagine it would be, necessarily) or if there is an east coast edition, but it is a very handy reference and will certainly further one's understanding of fertilizers, their various formulations and fertilizing in general. You can find used copies on amazon.com.

Well thank you both for your responses. up until about 2 weeks ago, i was the ONLY American working for this Dutch company. I was working like/with Mexicans and even though I have a degree in Biology, i was not very important. The Dutch dont look at resumes much. The head grower at the time was a 20 year old British bloke who did know a lot more, and went out of his way not to explain things to me. Then one day, hes fired, big opportunity for me. We do not have any injector irrigation. I have since learned a little more about these ferts, but my knowledge is far from complete. We apparently use the Urea on the Sedum in the summer to make it grow rapidly and then we cut it with our mower and use the cuttings for new fields. I thank you for your points of view, because it has become apparent that this company is "different" and everyone does things different. I will look into you suggestion for that book. the difference between the 19-19-19 and the 20-20-20 is one is granular and the other is soluble for our the dosatrons in our booms. any more advice will be taken under consideration.

Feel like a party crasher I haven't posted on Garden Web sooo long. LOL.
For what its worth "Western Fertilizer Handbook" is the fert primer .. I whole heartedly second Gardengal's advice.

Triple 20 and triple 19 were often used for fast growth in the early spring at wholesale nurseries. Many times that type of balanced fert was used in "in house" soil mixes for their container division. Controlled release fertilzers like "Osmocote" or other coated urea products are more the norm now.

You write that you don't have a irrigation injector. But you mention the "dosatron". A Dosatron is a irrigation fertilizer injector...Bob.

Urea applied to corn fields with added irrigation might make for a bumper crop.

ok see bob, what did i say, i need to learn a little more, i thought meant drip line irrigation. I have a huge thing for plans, but im more or less self taught, and there seems to be a few gaps in my education. thank you for all of your help. you will prob see more questions from me in the future.

I have been at this 36 years and made a lot of mistakes. In the plant business we have the advantage of burying our mistakes in the compost pile that is what compost was invented for... Bob.

If only all those chemicals stayed in the pile. See what community college or other courses you can take at the same time and gobble up all you can learn.

with a hort. program look for relevant trade periodicals, textbooks and books/articles from fundamentals researches these (link below), that you can pore through at night even if you can't manage attending actual organized lectures.

Here is a link that might be useful: Lacebark Inc. Books

I do have a desire to succeed in this business. I am currently looking into getting a Horticulture certification as well as a Commercial pesticide applicator certification for my own benefit and my company's benefit, but alas, my boss is dutch and is more concerned with saving money, making even more money, and has little to no concern with rules and regulations regarding pesticides and other such things. If i can get him to help me pay for it, I cant afford it. we will see... thanks everyone for you input

and has little to no concern with rules and regulations regarding pesticides and other such things.

Since he is so cost conscious, you might want to tactfully point out to the owner the liability involved in having NO concern about these issues. Fines for improper use and even improper storage can be significant. Depending on where you are located, even the local fire district may have input and if in violation of local regulations, can shut down the business. Ditto OSHA.

Are you telling us no one at the operation has a valid commercial pesticide applicator's permit? That could very well be in violation of Federal laws as well as VA state law, depending on what 'cides you are applying.

If any pesticide is used in your business the owner must have a private pesticide license and over see anyone applying pesticides or any worker like yourself must have a commercial license. The company cannot legally buy any pesticide without showing a license. Getting a commercial license for yourself is a great thing to have when you go to find another job in the plant industry...Bob.

ALL Excellent points, none of which i think they will care about. Like i said, they do things differently. I have reiterated a few times about fines and legalities to no avail. On of the dutch guys got a pest tech cert from the dmv and apparently you need 40 hours of supervised training, which he never got, yet he passed the test. we order pesticides all the time, and i dont think we have any sort of business pesticide license, because of course there is no one here certified to use them. but we do anyways, its usually done my mexicans... i cant just up and leave, because jobs like this arnt a dime a dozen, soo.... way i figured it, better my self, and the better off i will be when i leave. never thought i would have ethical problems at a greenhouse...

Well, it depends on which pesticides you're using. You don't need a license to apply all of them, just certain ones that work well!At least it's that way in Indiana, but states vary.
46-0-0 can be injected during summmer sparingly into bananas and tropical foliage plants for rapid growth, or on lawns.It would make a great sidedress for sweet corn too. 15-9-12 would be a good "dark weather" formula for carrying plants over the winter when there's not much light. Use it sparingly to keep stock plants in condition during the winter to do cuttings in spring. The one with the high last number would be good to use for fruiting bananas in warm climates, they prefer a high potassium for fruit formation. But I don't know what else to do with it. I think its most likely been used for a pot mum "finisher" fertilizer.

Careless pouring on of strong agricultural chemicals, including fertilizers turns the land used for such operations into toxic waste dumps. You should be using some kind of system to assess and monitor the need for and results from chemicals used on crops there. If nothing else, to minimize costs and maximize results.