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When you guys say put a pre emerge on your sunflower field, on old threads most of you are saying use spartan. How long after i plant sunflowers can i put out the pre emerge. I was getting the impression that some of you were putting it out the same day you planted the sunflowers. Is that correct?. I am assuming that sunflowers are not affected? Or have I got to wait for the sunflowers to emerge before I put out the pre emerge? Also can I put out fertilize the same day I plant or do I need to wait a few weeks before I put it out? Thanks

Pre-emerge herbicide is put out before the sunflowers and weeds come up. Spartan and Dual are a great combo. Throw in some roundup to kill what's already green.

I wait about a month after planting to put out my nitrogen. I use liquid. If you're putting out dry, try to do it right before a rain so that you don't lose so much of it into the air on hot days.

Ok thanks. On fertilizer do I need to just use a basic mix like triple 13, or would it be better to use a more specific blend?

You could do a soul test, but I only use nitrogen. Urea is your best source of nitrogen I believe.

I may have this wrong, but I think 1 gallon of N-sol (liquid nitrogen) is equal to 3.54 units. That is the same as 3.54 pounds of urea. I usually go with 20-25 gallons per acre.

On second thought lets revisit the fertilizer

1g 32N (liquid) = 3.54 units N

3.54lbs 46-0-0 = 1.63 units N

7.7lbs 46-0-0 = 1g 32N

Dry fertilizer nomenclature is percent of 100lbs, so each of the numbers is just the percent of product present.

50lbs 13-13-13
6.5lbs Nitrogen
6.5lbs Phosphorus
6.5lbs Potassium

Aha! Thanks for that clarification on the dry units.

So it takes 2.17 pounds of urea to get a unit of N or ,46 units per #?

So if you wanted 100 units, it'd take 217# of urea or 28 gal of Nsol.

Ok, now get this, at current prices, Nsol is $2.18/ gallon and urea is $.25/ pound. So on a per unit basis, Nsol will cost you $.62/unit and urea $.54/ unit.

However, that is not urea with the safener on it to keep it from vanishing into the atmosphere on a hot day like a fart in the wind. So you either need to plow urea in or get a rain on it soon after broadcasting, or spend a little more $ and borrow a knife rig and put liquid out with your tractor.

These are some calculations I ran a few years back.

Agrotain is the stabilizer we use when conditions are less than ideal.

You have to figure out what measurement(g,lbs,etc) then what % is whatever component your looking at. Then divide the desired rate(end result) by that percentage to get how many g,lbs,etc you need to put out.


1unit n / .46 = 2.17lbs 46-0-0

What's 28-0-0-5? Ammonium sulfate?

Yeah. Keeps my corn happy. Those calculations were examples of how to deal with the liquid side of things.