Are you familiar with the Next Door app for your phone? It’s the neighborhood connection application that allows you to post important area-specific updates or requests for household items or services. I’m subscribed to it, and most of the time I see updates on lost dogs or cats, or household items for sale. However, recently I’ve witnessed a passionate debate over what to do with tree leaves. Some members argue that tree leaves must be collected and never swept into the street, others say that leaves should remain on lawns to mulch the grass. There are also commentators who reminisce the days when the city would sweep and vacuum the leaves from the streets.
Photo Courtesy of the Minnesota Pollution Control Agency
What’s all this leaf hubbub about? When leaves fall in the street, they decompose and enter our street storm drains, going directly into lakes and rivers and contributing to algae growth in the following summer. The main nutrient that decomposing leaves lead to an excess of is phosphorus. While a few leaves aren’t a big deal, the aggregate amount of all leaves blowing into the storm sewers has a large impact on water phosphorus levels. In addition to algae being smelly and gross to look at, it also dies and decomposes at the bottom of the lake, using up oxygen that fish and plants need.
The Minnesota Pollution Control Agency (MPCA) and the Minnesota Department of Agriculture (MDA) both note that leaves should be taken care of due to their effects on water quality. The MPCA even offers information on the importance of street sweeping, and the MDA, as well as the Mississippi Watershed Management Organization offer the following suggestions on leaf maintenance:
- Rake or sweep-up: contain the leaves and definitely keep them out of the streets.
- Mow: according to the MDA, “if you have less than two inches of leaves covering your lawn, you can leave them in place and make several passes over them with a power mower. By shredding them into a fine, thin layer, you will provide your grass with valuable nutrients and end up with a lawn that looks like it was just raked. Gradually reduce mowing height to 2 inches to prevent winter turf damage.”
- Reuse as mulch or compost: if you collect the leaves, you can keep them (whole or shredded) throughout the winter and use them as spring mulch for your lawn or garden. If you compost, you could also add the leaves into your compost collection to use their nutrients that way as well.
- Bag-up for collection: after deciding to rake your leaves, if you have no other interest in using them then you can bag them to be picked up by your city or a yard waste pick-up provider. Call your city to find out who is the most appropriate leaf pick-up provider.
This leaf debate on Next Door is refreshing to me, because it’s leading to a fruitful conversation on how our interaction with the environment around us affects water quality. While we differ widely on our opinions on what to do with the leaves, we at least agree that something should be done.