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Mulch For The Vegetable GardenMaster Gardener Scoop – May 25, 2016

Master Gardener Scoop.pdf

By Jeanette M. Endres,

Master Gardener

By now, I have planted some of the garden and weeds are emerging. What mulch can I use to keep weeds from overtaking the plants? According to the University of Illinois Extension, researchers have shown striking benefits from mulch application. Mulches control weeds, hold moisture, prevent soil from forming a hard crust around plants and help maintain soil temperature. I want a mulch to control weeds. Mulches can help control weeds, but mulch material must be weed free and applied in a layer that is deep enough so seedlings that germinate cannot push through. Mulches do not eliminate weed seeds, plant diseases or insect infestations. Most organic mulch applications will have a slight cooling effect on the soil. See Illinois Vegetable Garden Guide (University of Illinois Extension) for planting times. Before mulching, I prepare the soil by eliminating all growing weeds. All gardeners should also consider having soil tested.

Compost, newspaper, cardboard, sun-dried grass clippings, sphagnum peat moss, leaves, shredded bark, and straw are some of the common plant-based organic mulches that can be used in the vegetable garden. They aerate heavy soil and deter weed growth. Brown mulches such as paper, bark, and straw have high carbon to nitrogen ratios and can reduce nitrogen available to plants. Therefore, fertilizing before mulching may be necessary depending on the results of the soil test.

Landscape fabric and plastics are inorganic and provide an effective weed barrier. If biodegradable, the fabric will break down under UV light from the sun. Biodegradable weed mats (Kraft paper) made from recycled paper are also available.

I use 3-5 inches of shredded paper, dry grass, straw or leaves. When using newspapers for mulch, I select at least a 4- 6 sheet layer of newspapers, keeping the mulch from touching the stems of plants. Paper, whether shredded or in sheets, tends to blow around. You can use compost, straw, dried grass, shredded bark or leaves to secure the newspapers.

There is still a debate over the safety of using the glossy colored insert pages from the newspaper. I contacted four local newspapers and received responses that the colored pages were safe for mulching since they use soy ink. A representative from the Illinois Department of Resources, when interviewed by the Chicago Tribune (November 11, 2001), stated that the only hazard of newsprint mulch is that “it gets kind of mushy when wet.”

Last year I used landscape fabric for my vegetable garden, spreading the black material over the ground and securing with landscape staples before I started planting. It definitely controlled weeds but was more expensive. The metal staples got lost in the garden or rusted and could not be used a second year. The landscape fabric I chose was not biodegradable. I had pieces of fabric in the garden this spring that had to be removed. Look carefully at the labels to make sure the product will degrade. Most landscape fabrics or plastics are expensive and designed for permanent landscape projects. This year I am using sheets of newspaper and shredded paper. I will cover the paper with at least a two inch layer of compost so the paper does not blow away. I considered straw as a good alternative, but I would have to purchase straw while I have an abundance of paper. Mulch works best on crops five inches in height, such as tomatoes and peppers, and later I will mulch cucumbers and zucchini. This year enjoy fewer weeds and better production of vegetables through mulching.

Mulch For The Vegetable Garden