Snow: Poor Man’s Fertilizer

The snow that dusted Fayette County last week made for some incredible landscapes. It may have also deposited a little nitrogen into the soil.

Rain, especially that which accompanies a lightning storm, contains a small amount of nitrogen. So does snow. It’s probably an even better source of nitrogen since snow melts slowly and doesn’t lead to a lot of runoff.

Farmers up north even call it “poor man’s fertilizer.” Research suggests snow accumulation can annually deposit up to 12 lbs. of nitrogen per acre in some parts of the country. That’s not a whole lot, but it’s something.

According to some northern gardeners, onions taste better if they’ve had some snow on them.

As snow or rain falls in the sky, it collects atmospheric nitrogen along with other nitrous compounds like ammonia that comes from fires, industrial emissions and volcanic eruptions. Water droplets can collect a small amount of this nitrogen. But the intricate geometry of snowflakes seems to collect even more of it.

The measly inch of snow that fell here probably didn’t deposit much nitrogen, probably less than one pound per acre. For perspective, a farmer growing corn might need 100 to 200 lbs. of nitrogen per acre to produce a good crop.

Human activity such as in-dustrial and automobile emissions seems to increase the amount of nitrous compounds in the atmosphere, and accordingly, in the rain and snow that falls. Researchers have found that the amount of nitrogen in snow is much higher in the more populous eastern U.S. than in the west – so much so that it has led to nitrogen pollution in watersheds.

Northern gardeners also sometimes refer to snow as a “poor man’s mulch.” Snow can protect some cool weather crops from freezing. A blanket of snow acts like a layer of insulation. Inside the snow, temperatures remain close to the freezing point while it can get much colder above the snow.

During the winter storm of 2021, a layer of snow covered my patch of kale, which can survive temperatures in the 20s. I thought it was gone for sure after temperatures dropped into the teens for more than a day. But to my surprise, the kale survived thanks to the blanket of snow.