# Using urea plus compost



## Joel_BC (Nov 10, 2009)

I've been building compost piles for many years using a three-bin system. Largely due to the fact that we mow a wild "lawn" of mixed grasses here, we have enough bulk. We add these clippings in with our garden refuse (chopped corn, tomato, and sunflower stalks, pea and squash vines, etc) and non-meat kitchen wastes. We get a fairly continual supply of compost this way.

As we know, compost piles lose nitrogen to the air as they heat and mature - you can often smell the ammonia coming off them. I know that many valuable essential minerals, as well as worms and micro-organisms are provided to the veggie-garden soil in which we incorporate the compost. But in my experience, nitrogen isn't supplied in enough quantity by compost.

Right now, we're keeping no animals here on our place. So - manure from neighbors' places being only sporadically avalable - I've tried watering my rows a few times per season with water in which I've dissolved manufactured urea (keeping it a pretty dilute solution). Manufactured urea is considered to be the same molecule that is found in animal urine, and requires the same organic bacterial action within the soil in order to be available for use by plants. Anyhow, the results have seemed very good: green leaves, robust stems, good production of corn, potatoes, leeks, beets, etc.

I may be missing something. And I wonder if anyone can point out any drawbacks to this practice, which sort of mixes organic and industrial horticulture?


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## Forerunner (Mar 23, 2007)

I've been harassed a good bit by some for mixing the old with the new, so to speak, but still have no qualms mixing rustic with modern, or high tech with low tech, to facilitate positive results. That said, having such access to fresh lawn clippings, you certainly shouldn't be experiencing any nitrogen deficiencies in your compost. You mention an ammonia odor coming off the piles, at times. That and most of your potential nitrogen and other losses could be eliminated with an addition of six inches of sawdust to create a sponge/buffer shell to retain and protect the more valuable nutrients inside. Straw or leaves or any dried organic matter would serve the purpose, but, the finer it is chopped, the better.


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## Paquebot (May 10, 2002)

The smell that you're getting is most likely more methane and natural odors than nitrogen. Some nitrogen must be lost in decomposition as that's the nature of the process so there should be some ammonia smell when it is active. Using the green material that was mentioned, there'd be Little or no need for urea during the time when they are available. But for fall and winter, urea would be a great accelerator to get an otherwise out-of-balance C:N ratio mix working under cooler ambient conditions.

Martin


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## Joel_BC (Nov 10, 2009)

Paquebot said:


> The smell that you're getting is most likely more methane and natural odors than nitrogen. Some nitrogen must be lost in decomposition as that's the nature of the process so there should be some ammonia smell when it is active. Using the green material that was mentioned, there'd be Little or no need for urea during the time when they are available. But for fall and winter, urea would be a great accelerator to get an otherwise out-of-balance C:N ratio mix working under cooler ambient conditions.
> 
> Martin


Thanks. But I believe I must have been a bit unclear and what I wrote. I'm not using the urea in the compost... not using it to adjust the C:N ratio, to accelerate.

I've been putting our compost into the soil in the veggie patch. Then, after a week or two, I water the rows in the patch using a dilute urea/water solution. And I may repeat this two or three times during the growing season (which generally is about 100-120 frost-free days, here).

Urea is said to be 46% by weight. That's strong, so when I dissolve it, I make sure it's not so strong as to burn plants.


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## Paquebot (May 10, 2002)

Right you are but you wouldn't have to go through the trouble of mixing and watering if the urea were an integral part of the compost. Your method is the quickest way to get the nitrogen to the roots but you're sure to lose a certain percentage. There are farmers who add urea to their manure just before spreading and plowing it under. Other than some loss into the atmosphere, applying urea as a spray is common practice as versus knifing it in. So, you're doing OK and your plants will appreciate it. It's not any worse than if you used horse manure.

Martin


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## Jenn (Nov 9, 2004)

And don't forget the urea available from the tip of your- erm- well it's a lot easier for you, I have to collect mine in a bucket usually inside and transport- you can add free urea on the spot if your heaps are private enough. (In case my cuteness is too vague, PEE on your compost heaps and don't bother with buying urea.)


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## geo in mi (Nov 14, 2008)

I think you might be okay if you are doing that because you have made soil sample analysis and aren't overdoing the N uptake in your leafy vegetables late in the year--lettuce, spinach, kale....There are some opinions that too much N in these veggies are harmful(it would take some digging to find the source of that opinion) Most commercial bag fertilizers use urea as a major nitrogen source, so you might get the devoted organic folks p***ed off at you. But, hey, it's your garden....... And your stomach......(And a bad joke if you caught it)

Seriously, if you have the luxury of creating several paddocks to rotate your garden through, you could devote each paddock to intensive soil-building--using legumes, green manures, and some fertilizers there to absorb and hold until used for the vegetables. If not, you can at least rotate nitrogen users into areas where nitrogen fixers were grown the previous year. And use understory legumes and quick compostable cover crops in otherwise idle spaces--oats, turnips, grocery store Great Northern beans, buckwheat.

My compost is pretty N hot, because I use fish heads and parts--now there's a real smell--so you might use fish emulsion if you want to stay organic. Just a thought.


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## Joel_BC (Nov 10, 2009)

geo in mi said:


> Seriously, if you have the luxury of creating several paddocks to rotate your garden through, you could devote each paddock to intensive soil-building--using legumes, green manures, and some fertilizers there to absorb and hold until used for the vegetables. If not, you can at least rotate nitrogen users into areas where nitrogen fixers were grown the previous year. And use understory legumes and quick compostable cover crops in otherwise idle spaces--oats, turnips, grocery store Great Northern beans, buckwheat.
> 
> My compost is pretty N hot, because I use fish heads and parts--now there's a real smell--so you might use fish emulsion if you want to stay organic. Just a thought.


I used to rotate my patches, putting in a green manure cover crop for a year on the fallowed areas. But more recently, I've been using all of my garden areas - the reason being that I established more extensive permanent plantings (berries). However, I still will often plant fall rye, and till that in the following spring. But I agree with you that legumes are the ones that fix nitro into the soil.

I have used fish emulsion, on and off, over the last 20 years. However, it has been getting more expensive. It's mainly the nitrogen boost that I need, knowing that fish contains more than just that, and since I believe my compost and straw mulches provide pretty well what I need besides the N. Sometimes I'll invest in some gypsum for calcium; I don't generally use lime because my soil pH runs 6.8 - 7.2 pretty well everywhere.


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