The last fall feeding should be after the top-growth has stopped but before dormancy sets in. My preference is for urea (46-0-0) spread at the rate of 2# per1000 sq.ft. Urea is a synthesized organic compound identical to urea found in urine. Orthodox organic gardeners would probably not use urea but many organic lawn practitioners deviate from strict organics and use urea for the last Autumn feeding. There is a debate going on now in the lawn forum concerning urea as a Fall fertilizer. If you are going to use SBM or Milorganite, you will need to get it down early enough for the soil microbes to process it, releasing its nutrients to grass before dormancy. Of the two options you offered, my choice would be Milorganite because of the 4% Iron contained therein.
Bill Hill

Since Urea is a synthetic material, unacceptable to an organic gardener, it should not even be mentioned on an organic forum. The material to use now, depending on where you are, is the Milwaukee sewage or others similar product.

kimmsr, why are you suggesting putting down something this time of year that requires microbial activity to be of any use? I understand this is the organic lawn care forum, but there's no reason to tell people to waste their money. I'm guessing by the OP's nickname that he's from North Carolina, and the soil there is much too cold for the Milorganite to do any good now.

This is straight from the Milorganite site:

"Microbial activity occurs when soil moisture is adequate and the temperature of the soil is between 55 and 85 degrees (F)."

The only places left with soil temperatures consistently in that range are in the far, far South of the states.

Unless my thermometer is way off my soil temperatures here are still in the 40's, so in North Carolina they should be much warmer, which is why I suggest getting your own thermometer rather than rely on internet charts. Also, since the snow we have had this week is still melting about as fast as it falls that suggests to me that soil tempeeratures are warmer than I have seen on these internet charts.

kimmsr, the soil temperature in Tidewater, NC is currently 56.48 *F. That is right at the very bottom end of the range given by the Milorganite people, and the soil temperature is only going to get colder as we head closer to winter. I'm not sure what "internet charts" you're looking at, but I would think the stations set up by the United States Department of Agriculture would be pretty accurate. Most of them are real-time stations as well. Have a look for yourself, it's a pretty neat site:

http://www.wcc.nrcs.usda.gov/scan/

My point is that it's too late to put anything down that uses microbial activity to work; it's not going to do anything now that the soil has cooled as much as it has.

I'm near Charlotte. Our soil temps are still in the lower end of that range. But if it's that close, I may not do anything else this year.

I wouldn't put out anything like the urea that bill mentioned by the way. That stuff is full of salt.

Urea is product that always garner some debate regarding its level of "acceptability" in an organic program. In its original form, urea is about as "natural" as it gets. Although I understand it isn't made that way anymore.

As a starting point, I use it. Frankly, I use 95% organics but do not try to be "holy" in my approach to the term and practices. I don't sell anything off my yard that requires compliance with any guidelines to not constitute misrepresentations, etc. I do what I think is healthiest for my yard with some consideration to overall effects on the environement. In that regard, even use of some "organic" products can be harmful if over applied or not done correctly.

I think a small once a year app of a even a clearly "chemical" nitrogen source probably would not have a big deleterious effect on the soil and yard. Though I am open to real scientific study on that, I haven't seen any in several years of staying on the lookout for it. I used ammonia sulfate before swithching to urea in the hopes (though I have no studies to base it on) that urea is a little better from an organic point of view than AS.

Now, for those who want to be absolutely sure they are 100% organic, for whatever reason, they are entitled to their approach as well. I just don't think anyone has the ability to say on the urea issue it is set in stone.

Alright, so in doing some reading on urea, it may sound like a good option for the last feeding. What effect will it have on the grass in the early Spring? I don't want to force a really early green-up.

The past two Springs my grass has lagged a little behind my synthetic neighbors. That's OK. It is my understanding that during this early Spring time frame, there is a lot of root development happening. I don't want to force so much top growth that it interferes with root development.

What do you think?

Quick story: About 6 weeks ago while spreading SBM, I unknowingly spilled some on the grass. I discovered it a couple days later. It was the size of a shoe and about 3 inches deep. I spread it out with my hand and flung it around. But it had already been rained on so I wasn't able to get all of it up.

A week or so later, I noticed the area starting to yellow a bit. A couple weeks later the yellow spot went away and the spot was the same darkness as the rest of the grass. Recently I noticed the spot again. Only this time it was darker green than the rest of the lawn and growing a little faster.

In short I wish the entire lawn looked like that spot. My lawn looks great. I'm happy with it, but I didn't know it could look... better.

tarheel,

You should give this article a read. It looks like from the research that's been done, giving the lawn a late fall application, once the top growth has stopped, causes the grass to store the carbohydrates all winter long. This allows an early Spring green-up, but without all of the excessive top growth. Definitely give the article a read.

My personal experience with urea has been that it keeps the lawn noticeably greener here all winter long and causes it to green up much faster in the spring.

My soil felt nice and soft to walk on (when moist) before I started using it with my other organic program and has continued to have that same, or better, feel since. More or less microbes, I don't know, I haven't tried to measure them.

Great read skizot. Very good info that I will follow. Thanks.

Thanks for responding in this thread guys.

Here's a few more non commercial, university studies, supporting nitrogen for the final feeding.

http://www.coopext.colostate.edu/4DMG/Lawns/mythwint.htm

http://www.agry.purdue.edu/turf/tips/2005/octf1024.htm

http://web.extension.uiuc.edu/regions/lawnandgarden/FallLawnCareGuide.pdf

http://www.gardening.cornell.edu/homegardening/scene3de4.html

All of the Urea you can buy today is synthetic and is unacceptable to an organic gardener/farmer. Any product that has a Nitrogen level in the double digits is synthetic because "natural" sources of N will not get that high.

I guess, kimser, it kind of depends on what your definition of is is. ;)

What is an organic gardener? Cow piss is about as natural as you can get and its in double digits. Your definition is a little too rigid for my tastes. But, to each his own.

Is it good for the grass and ok for the soil and environment if used wisely? As far as I can tell, more yes than no. So, to each their own.

Kind of borders on folks deciding whether baptism needs to be dunked or sprinkled. I won't chastise your choice if you won't mine.

Hi eveyone,I live in northeast ohio, zone6,I'm new to this lawncare forum.I've been wondering what to use for my last fall feeding,the guy at my local lesco store said there is no such thing as winterizer fertilizer.I've been reading your post about using urea.Is it ok for me to use it in my zone?

"Is it ok for me to use it in my zone?"

It all depends on how organic you're trying to be, and that is something only you can decide.

Urea that you buy as fertilizer is chemically indistinguishable from urea produced by animals, but it's created synthetically, so it's not an organic fertilizer in that sense.