It’s spring, and vegetable and flower gardens are on the minds of many. So are plush green lawns. But before you get started spreading your fertilizers and lawn treatments, stop to consider what you’re doing, and if you really need to do it.

It’s accepted by now that fertilizer run-off, from farm fields and home applications, accumulate in our streams and waterways and contribute to algae blooms. Both the toxic algae that force municipalities to shut down their water filtration plants, and the green slimy stuff that looks bad in your pond. There are many ways to combat this issue. One is to simply spread less of the product, or to try to not spread it before the sort of heavy rains that can lead to it all washing away into the streams before it can benefit your lawn anyway.

In agricultural applications, farmers can leave a buffer of trees and plants between their fields and streams or creeks. These plants can absorb that extra fertilizer before it enters our waters and contributes to algae blooms. But that requires farmers to take valuable acreage out of production to create that barrier, and not all of them can afford to do that.

The commercial agricultural applications are, of course, the major source of fertilizer runoff, but home use contributes as well.

And if your lawn care product is primarily nitrogen and phosphorus based, as many are, you may not even need it at all. At least, not in Ohio.

Studies going back to the late 1990s show that agricultural areas of the Midwest, including Illinois, Indiana, and Ohio, have significant levels of nitrogen in their rainwater already. In Ohio, these nitrogen levels range from 5 to more than 7 kilograms per hectare. While this may not be enough fertilizer if you are commercially growing corn or wheat (it would be around 5 to 15 percent of your needs, respectively, for those crops), it probably means you don’t need to fertilize your lawn.

So, while you might still want to spread manure or compost on your garden for phosphorus, and might even be OK using a liquid fertilizer when you water, think twice before you fertilize your lawn. Ask yourself if you really need it. Chances are, with a little TLC, you can do just fine without adding any fertilizer, and save yourself a little money at the same time you’re helping save the creeks from algae.

When in doubt, manure-based sources of phosphorus are less intense than chemical fertilizers, and lead to less environmental accumulation.