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How to Add Urea to Compost

dead leaves image by Stephen Gibson from

Gardeners without regular access to moist, green organic waste, such as fresh grass clippings, often turn to urea to provide a boost of nitrogen to their compost heap. Nitrogen is an essential compost ingredient that helps jump-start the microbial activity in your compost heap, which helps speed up the composting process; urea is a synthetic chemical that contains 48 percent nitrogen, according to Steve Solomon, author of “Organic Gardener’s Composting.” A little bit of urea goes a long way, so use it with caution in your compost heap. Look for this synthetic nitrogen source at your local lawn and garden center.

Shred and chop up the organic waste you plan to use in your compost heap. Cut or tear newspaper and cardboard into long, thin strips that measure no more than about 2 inches wide. Feed dead leaves through a leaf chopper or drive over them with a push mower. Saw or break large sticks and branches into small pieces that measure less than 3 inches in diameter.

Mix together all the waste you have into a large heap. Blend each type of waste evenly throughout the pile with a rake to create an even mix of the different materials.

Shovel away any turf or grass from a 3-by-3 foot area of soil at your compost site. Rake an 8-inch layer of the organic waste over the bare soil. Dampen the compost materials with a gentle spray of water from your garden hose; add enough water to make the organic waste about as damp as a wrung-out sponge.

Sprinkle ¼ cup of the urea evenly over the entire layer of compost waste. Top the urea with a 1-inch layer of plain topsoil to provide additional decomposing bacteria in the compost pile.

Spread another 8-inch layer of compost waste over the plain topsoil, dampening it with water. Top this organic waste with another ¼ cup of the urea fertilizer and another 1 inch of plain topsoil. Repeat the alternate layers of damp organic waste, urea and plain topsoil until your compost heap measures 3 feet tall.

Mix the layers of compost together once every few weeks with your garden rake to aerate the pile, which increases microbial activity. Make sure the compost stays damp; squeeze a handful of waste to ensure that you can wring out one to two drops of moisture. Add extra water if necessary.


Since urea is a commercial fertilizer, adding it to your compost heap keeps your finished compost from being organic. If you plan to sell or share some of your compost, make sure your customers and friends are aware of this, since they may be using the compost on organic garden produce.

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