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It's World Soil Day!

A smiling girl plants a plant in the dirt with help from her father.

December 5 is World Soil Day. Find out how to grow healthy soil that can filter and break down many pollutants.

Initially recommended by the International Union of Soil Sciences in 2002, World Soil Day is a time of education and advocacy for sustainable soil management. Soil health remains critical as the demand for food around the world increases. Did you know that more than 95% of all food comes from soil? Produce requires 18 natural chemicals to thrive, and the dirt they’re planted in provides 15 of those chemicals.

What does healthy soil look like?

First, it should have a healthy cover of green vegetation like wildflowers, grass, weeds, or other plant life. Bare, uncovered earth can indicate that something isn’t right.

Next, observe the color. The darker the dirt, the more organic matter there is. You should also see plenty of activity from small organisms like earthworms and fungi. Healthy soil also tends to crumble off the roots of vegetation that you pull up.

Even the smell can be an indicator that your ground is healthy. The rich, earthy smell is known as geosmin, and it’s created by active soil bacteria. If you don’t want to sniff dirt, the King Conservation District offers free soil nutrient testing.

How do I grow healthy soil?

Healthy soil can filter and break down many pollutants. Instead of using chemical fertilizers, pesticides, or herbicides that can harm people and pollute the environment, it’s better for you and environment to feed your soil with compost. Here are some tips for how to use compost at home:

Till compost into your soil prior to planting your garden and mix 2-3 inches of compost into the garden bed. For a healthy lawn, apply 1-2 inches of compost.

Don’t forget to mulch! A layered spread of organic mulch on the surface of your soil can conserve water, keep weeds at bay, and feeds the dirt over time. You can use a variety of materials for mulch, such as fallen leaves, compost, grass clippings, straw, and wood chips. You should spread mulch over bare soil, but avoid woody stems and tree trunks. Reapply your mulch every year.

Talk to the experts at The Garden Hotline to learn more about soil, lawn, and gardening care. You can reach them between 9 a.m. and 5 p.m., Monday through Friday at 206-633-0224, or send them an email at

How can I celebrate World Soil Day?

Consider planting a tree. Trees and other vegetation with healthy root systems slow down erosion and increase aeration and water penetration. If you don’t have somewhere to plant a tree at home, consider volunteering with a local charity or organization that supports reforestation. You can also try reducing your food and plastic waste.

Follow this link to the United Nations Food and Agriculture Organization website for more fun ways to celebrate.

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