The Homeowners Column

The Homeowners Column

What's the Matter with Organic Matter?

Photo of Sandra Mason

Sandra Mason
State Master Gardener Coordinator

As gardeners we always want to add something to the soil. Like frustrated cooks looking for the perfect chili recipe, we add a dash of this and pinch of that. Before adding anything, it is best to get to know your soil. So tonight put your ear to the ground and listen carefully.

Ok, just kidding on that one. First get to know your soil with a soil test. Soil test results measure soil pH and the major nutrients used by plants (nitrogen, phosphorus, and potassium). They may also include calcium, sulfur, and magnesium as secondary nutrients. Also ask for organic matter levels which should run 3 to 5 percent. Assorted soil testing labs are listed at

Generally you can't go wrong by adding organic matter as it adds important nutrients and microbes to the soil and aids with soil drainage. Think of feeding the soil rather than feeding plants with fertilizer. If possible add organic matter to whole gardens rather than just the planting hole. Good soil in the planting hole but lousy soil all around encourages plant roots to stay in their happy planting hole never to venture out into the cruel world.

However, some plants grow better without a lot of organic matter. Perennials with runners or rhizomes such as mint can get down right invasive if they are planted in soils with high organic matter. Lavender and baby's breath prefer a sandy rocky soil.

Some common organic matter products added to soil:

Peat Moss - Peat moss is partially decomposed sphagnum moss harvested from Canadian peat bogs. Peat moss is often recommended but comes with a huge environmental cost. Peat harvesting permanently changes the water relations of the bogs so that natural regeneration is impossible. It also degrades the area for the plants and animals that call the peatlands home.

Coco fiber - Coco fiber is an environmentally sound byproduct of the coconut industry and makes a good substitute for peat moss. Coco fiber is sold in bricks, literally the size of house bricks, which are easy to transport and store. Once wet the coco fiber swells to 3 cubic feet. Coco fiber is free of weed seeds and diseases and does a good job of holding nutrients and water in the soil. Add warm water and wait at least one hour to wet products thoroughly.

Compost – ah, the elixir of the garden gods also known as black gold as it adds important nutrients and microbes to the soil. It's also the best solution for improving the drainage of clay soils. Make your own compost or buy local. Check with your city for municipal sources such as The Landscape Recycling Center 1210 East University in Urbana PH: 344-5323. Contact local livestock producers but be sure to get composted manure such as Ewe Poo Compost

Mushroom compost – Mushroom growers use their own special recipes to grow edible mushrooms. Once their harvest season is complete the old compost is sold to garden centers, nurseries etc. Mushroom compost can be good for garden soil; however, it can be too much of a good thing for seeds and seedlings. Soluble salts and other nutrients in fresh mushroom compost may be too concentrated for seeds, immature plants, and acid-loving plants such as rhododendrons and blueberries. Be sure to mix mushroom compost with garden soil or check to see if your supplier has allowed the compost to continue to "ripen" for a couple months before usage.

Saturday May 11 from 8 AM - 1 PM Grand Prairie Friends Native Plant Sale inside Lincoln Square, Urbana along with other groups such as CU Herb Society.

Saturday May 11 from 7 AM -1 PM Vermilion County Master Gardener Plant Sale at Crossroads Church 3613 North Vermilion in Danville. Help fund local community garden projects.

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