By relying on natural nutrient cycles and compost, you can have an attractive landscape without using synthetic fertilizers.
Every year, many homeowners spend money fertilizing their lawns, but is it worth it? Fertilizer is often touted for lawn care, but in Texas synthetic fertilizers are not required to maintain healthy grass.
Healthy soil, good mowing practices and natural nutrient cycling can provide all the nourishment lawns need not just to survive but also thrive.
Applying synthetic fertilizer can create environmental problems when nutrients are washed off landscapes during rainfall and by sprinkler systems. Excess nutrients can then enter creeks and rivers, where they contribute to water quality problems both locally and downstream.
What does fertilizer do?
Most lawn fertilizers contain three primary nutrients: nitrogen (N), phosphorus (P), and potassium (K). The warm-season grasses we grow in San Antonio including Bermuda, St. Augustine and Zoysia do require these nutrients to grow and help tolerate stress. But lawns often get far more fertilizer (and nutrients) than necessary.
One of the most important sources of natural nutrients for grass is grass clippings. When clippings are just left on the lawn after mowing, they break down quickly and return natural nutrients to the soil. There’s also the added benefit of not having to empty your mower bag into the compost bin!
This practice is called grass cycling, and it can supply most of the nitrogen grass needs each year.
Organic matter in the soil also contributes beneficial nutrients to grass over time. As leaves and compost decompose, they gradually release nutrients while also supporting beneficial soil microorganisms and improving soil quality.
Why can synthetic fertilizer be a problem?
Unfortunately, fertilizer that is not used by your lawn doesn’t stay in place. During rainstorms or even during regular watering cycles with your sprinkler system, excess nutrients can wash off your lawn and enter creeks and rivers.
The extra nitrogen and phosphorus in waterways can lead to excessive algal growth and lead to a process called eutrophication. When the excess algae die and decompose in water bodies, oxygen levels in the water can drop rapidly, harming fish and other aquatic life.
As a former fish biologist, I’ve seen firsthand how excess nutrients can have negative impacts far beyond neighborhood streams. In fact, excess nutrients from urban landscapes and agriculture contributes to the annual hypoxic ‘dead zone’ that forms in the Gulf of Mexico, where oxygen concentrations become too low to support many marine organisms.
Because of these negative impacts on aquatic life, many Gulf Coast communities restrict fertilizer applications during the rainy season or limit the types of nutrients that can be applied to lawns.
Although San Antonio is located inland, our waterways are still connected to downstream ecosystems. Nutrients from fertilizers that wash off lawns can enter our local creeks and rivers.
In recharge zones, some nutrients may also infiltrate the aquifer, while others may eventually flow downstream through rivers toward coastal estuaries. As marine biologist Rachel Carson famously wrote in Silent Spring, “In nature nothing exists alone.” The choices we make for our landscapes can influence water quality far beyond our own yards.
Supporting your lawn naturally
Healthy lawns can thrive without the addition of synthetic fertilizers. Here’s a few simple practices that won’t break the bank (unlike synthetic fertilizers) and provide the nutrients your lawn needs while improving soil health.
- Leave grass clippings on the lawn.
Save yourself some time and just leave the grass clippings on the lawn to allow nutrients to return to the soil naturally. You don’t need a special mulching mower, but grass cycling results may be improved by using one, or by replacing your mower blade with a mulching blade.
Mow regularly.
Mowing your grass regularly at the correct height encourages dense grass growth. Mow often enough that each mowing only removes about 1/3 of the grass blade. Raise mowing height during the summer to reduce moisture loss and encourage deep root growth.
- Add compost in early spring or late fall.
Apply a thin topdressing of compost over the entire turf area to a depth of about 1/3 inch. Spread the compost in piles on the lawn using a wheelbarrow. Then use a shovel to distribute compost and a push broom to sweep it off the grass blades and into the turf.
- Don’t rake your leaves.
If you leave your leaves or mow them into the lawn, they’ll break down and help fertilize your grass. Leaves contain nitrogen that your lawn can use, and they’re free! If you don’t like having too many leaves on your lawn, just rake them up and spread them in your landscape beds instead — they make an excellent garden bed mulch.
Having a beautiful lawn in San Antonio doesn’t have to come at the expense of the environment. By following a few simple steps, like grass cycling and using compost, you can save money and have a healthy lawn while helping keep our waterways healthy, too.
Sometimes the most sustainable lawn care practice is to simply skip synthetic fertilizer and allow natural processes to do the work.
