Mulching

Written by Scott Reil

One of the finishing touches to any garden is mulch. It performs a wide range of functions in the garden besides simply dressing the bed or border. Mulch helps deter weeds, maintain moisture, lower soil temperatures and eliminate soil erosion. Despite the multitude of tasks it accomplishes most of us give it little or no thought and go with the cheapest model available. Let’s take a closer look and distinguish between the good and bad and find the best mulch for your situation.

Chippings or trail chip
One commonly available form is chippings or trail chip; it is very tempting to tell the tree guys cutting around the power lines that you have a place they can dump their chippings so you can get yards of free mulch. But let’s look closer. Those solid wood chips

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require microbes to break them down. The microbes require an alternate food source to generate the energy to do that and they use nitrogen, the very same food source as your plants! So the mulch you are putting in to assist your garden is actually stealing food from it!

Red mulch
Some of the mulches most often sold, fall into that same category. Red mulch (often sold as red “cedar” mulch) is really chipped up pallets, died with a food color (Other colors now available are the same thing, different dye). These mulches break down in the same way that the trail chips do with the same consequences. But because the dye washes out, we replace it yearly leading to geological layers of nitrogen robbing, water excluding of wood. This is the exact opposite of what we should be trying to accomplish.

Bark mulch
Bark mulch is just that; the bark of trees, not the trees themselves. Most of the bark mulches are made of softwood like pine, spruce, hemlock and fir. These biodegrade easily without the nitrogen issues of the previous mulches. They also create dark rich soil that actually helps to feed the plants they protect. Although it is more expensive, the trade between degrading our soil to improving it, is worth the extra money. (Actual red cedar mulch is expensive, but it is the best answer for banks and hillsides as it has all the above properties and it mats together because of its stringy properties).

Compost
Compost is wonderful mulch you can make at home from leaves, grass clippings and food scraps from the kitchen (coffee grounds, vegetable peelings and the like; no meat or fats). The main problem here is making enough of the good stuff to cover your gardens; I reserve mine for the roses and a few chosen veggies (tomatoes love it). Some towns actually make piles of compost from garden waste and give it away free; check and see if your town is one of them. The savings will be considerable and you’ve already paid for it in taxes.

Stone or rubber mulch
While some feel they are saving time and money by using stone or the new rubber mulch, I would say they are fooling themselves. It may take five or ten years, but that stone mulch will eventually fill with leaves and detritus, followed by weeds and then what? Another layer of stone? Soon you create an anaerobic situation for the roots of your plants. Meanwhile the plants continue to deplete the soil nutrients; you can replace them with fertilizers, but most of that nitrogen is water-soluble and washes out with the next rain, polluting our lakes and streams. Good mulch replenishes organic content in the soil and organic fertilizer stays in the soil to be taken up by garden plants not algal blooms.

Other mulches
There are other organic mulches on the market like buckwheat hulls, cocoa mulch and licorice root; each has its own positives and negatives, but to my mind, for the cost and effect, bark mulch remains the best choice. We accomplish all the tasks we set out to while replenishing organic content in the soil, thus feeding our garden in an ecologically responsible way and getting dark crumbly soil, not layers of deadwood. So before you add that final touch to the garden (and mulch is certainly the best looking way to finish a bed), think about what you want for your garden. And if you’re still undecided, try bark mulch in one garden and your regular brand in another and see which bed has more worms at the end of the year. Millions of worms can’t be wrong….