Mystery Wood Chips for a Magical Garden

Note that this article refers to bulk wood chips, possibly of unknown origin, and not wood chips sold in bags specifically for decorative or garden use. For example, some cities collect fallen wood after storms from the streets, run it all through a chipper shredder, and allow citizens to truck away as much as they want for personal use in gardens and landscaping. Certain urban waste facilities or school campuses may also offer this service.

If you have been fortunate enough to acquire a quantity of such wood chips, this article will help you understand how to utilize them successfully in your organic and magical garden.

So you've acquired some wood chips, consider these questions:

Are they infected with termites?

Is the wood is from dead or diseased tree(s)?

Are the chips from an urban disposal facility, and if so, are they contaminated with heavy metals, pesticides or herbicides?

Is the wood freshly chipped?

There are a lot of potential disasters in a seemingly innocent pile of mulch, but mulch can also be as good as gold in the garden. To prevent potential disasters, follow these tips:

Don't use freshly chipped wood on your home garden.
Generally, pine chips can be used when they are new and freshly chipped, however there are several reasons you will want to allow almost any wood chips to age and mellow before using them in your garden. Fresh wood chip mulch will steal nitrogen from plants, causing deficiencies and possibly even death. Also, certain types of wood are allelopathic (more on this below) particularly redwood, walnut, eucalyptus and cedar. And finally, fresh wood chips may contain pathogens - insects or diseases that can infect the plants & trees around your home. Insects in the wood, such as termites, could also invade your home & outbuildings.

So, what can you do with your pile of gold?
First, let it age at least 3 to 6 months to ensure that it doesn't leech nitrogen or cause nutrient deficiencies in nearby plants. To age your wood chips, you just let them sit. You might want to cover it with a tarp if you live in a rainy area, because if it is moist, it will begin to compost. This isn't a bad thing necessarily, but assuming you wish to use these wood chips as landscape or garden mulch, or as footpath material, you'll want to avoid allowing it to compost.

A side note on the topic of composting:
Composting wood chips can release nutrients, kill insects and pathogens and be entertaining. Watching the steam rise from the pile of chips on cool early mornings has a certain charm. The interior of the pile can reach 140 degrees or more, which should be sufficient to clear it of most bugs and diseases.

If you want to intentionally make your wood chips compost, pile them up about a meter and a half (4 1/2 ft) tall pile, and however wide is necessary to accommodate your quantity. Water the pile thoroughly and allow the moisture to soak in. Next, water the pile again with a water soluble fertilizer that is high in nitrogen. Manure tea is ideal for this. Keep the pile about as moist as a wrung out sponge.

In a few days, the interior of the pile will feel hot as the composting begins. If it starts to smell vinegary or offensive, stir the pile a bit to increase the air circulation in the center. The scent of vinegar from the pile can be an indication of acetic acid building up. This acid can harm plants, but is easily prevented by stirring the pile. If the pile smells like male cat markings or ammonia, stir and "turn" or fluff it well. Within a few hours to a day of turning/stirring the wood chips, offensive smells should subside.

Anyway, sorry about getting side tracked (I have a tendency to do that with the gardening topics). Now where was I, oh yes, let it age 3-6 months, or even partially compost it during that time if you like. Next, check it out closely. Look for bugs, chips of metal, bone, fur, rot, etc. If you are good at mushroom identification, sometimes the species of mushrooms growing on the pile will help you determine the species of wood it contains. If you aren't good at fungi, don't worry about it.

When in doubt, assume that your wood chips contain allelopathic woods. When people say it is bad to mulch with so-and-so wood (usually walnut, cedar, eucalyptus, redwood, etc.) they will follow by saying "because it is poisonous" or "because it is acidic." The word they are looking for is allelopathic. This is a phenomenon known to humans for hundreds of years (Pliny wrote about Walnuts being toxic to other plants over 1900 years ago) Some plants have chemicals that inhibit the growth of other plants, or the germination of seeds. Organic gardeners use these natural chemicals as herbicides by growing cover crops of allelopathic plants like dandelion, rye, red clovers, etc., or by juicing these plants and spraying the juice onto garden paths and other weed prone areas . . . okay, getting side tracked again . . . so allelopathic refers to a plant containing toxic substances that suppresses the growth of other plants.

Many woods have some allelopathic compounds, but do not pose as much a threat as walnut, cedar, eucalyptus and redwood. Allelopathic woods that are not as dangerous to use include black locust, spruce, sassafras, sugar maple, hackberry, larch, cottonwood, red oak, black cherry, douglass fir, hickory, pecan and many more.

The weed suppression action of allelopathic wood chips can work in your favor, especially when using the chips in foot paths. However, if you use allelopathic wood chips in your garden beds, and the concentration of allelochemicals is too high, your plants will get sick or die.

Again, just assume any wood chips of unknown origin contains some allelochmicals. After aging it and inspecting it closely, use it only around established plantings such as trees and shrubs. Use it sparingly, such as a one inch layer or less, or mix it with other much if you need a thicker layer. Never, ever use mulch of unknown origin on food crops!

Now I don't want to give the impression that mulch is a bad thing, it really is garden gold! It cools the soil, prevents erosion, suppresses weed growth (when applied 2 inches deep or more), prevents plant stress from heat and drought, provides moisture and even temperatures required by spiders and other insect predators, breaks down slowly to provide time-release fertilizer, increases beneficial soil microorganisms, and so much more! But it can only do these wondrous things when used correctly.

Don't mulch closer than 6 inches to a tree or large shrub trunk, and not closer than 2 inches from small plants & shrub trunks or stalks. And again, don't use mystery mulch on food crops. Mystery mulch, especially from urban recycling programs, may contain heavy metals or other contaminants that can be taken up by your food crops, eventually ending up in you.

Tips for New Garden Locations and Homes
If you know where a new garden is going to be, and know that the location won't be driven over during any construction, you can lay down mulch paper now along future paths. Then, spread wood chip mulch over the paper about 3-6 inches deep. The paper will help prevent too-quick breakdown of the wood, and keep it from taking too much nitrogen from surrounding trees if there are any. The mulch paper will also help prevent weeds from growing up through the mulch.

If you aren't sure where the garden will be, you can still make paths, but might want to forget about using mulch paper. The paths will provide a place for you to walk around and dream about your future plans for the site, and paths will also help keep people from trespassing or dumping on your property because it will look more "lived in."

Final Notes
Many landscapers use redwood, cypress or cedar mulches because they resist rot well, and they usually choose large bark nuggets that will decompose very slowly. This is useful for low maintenance landscapes around schools, businesses, city and commercial buildings because it won't need to be renewed as often, and because these woods contain weed suppressant allelochemicals. These mulches are normally used in conjunction with professional grade landscape fabric rated to 20+ years. This landscape paper keeps the mulch from contacting the soil.

Some mulches are also high in tannin and acid, especially oak, pine needles, etc. These decompose slowly, may sometimes hinder other plants' growth and acidify the soil, but they can also be used for growing certain plants that like to live under oaks or pines such as rhododendrons, mountain laurel, etc. In small quantities, these mulches won't usually do much harm. When used carefully, the allelopathic woods, and acidic or tannic woods, can be quite effective and are not "bad" mulches, however they are best left to the professionals or to experienced and knowledgeable gardeners. As a very, very general rule, choose pine chips when in doubt, and for food crops use compost, straw or hay.

In summary, the safest bet for using mystery mulch would be to age it and use it for paths away from buildings, or compost it nice and hot for a year before using it in garden beds located near buildings. And remember, mystery mulch should only be used on non-food producing areas of your garden.

Copyright © 2007 by PaganPath.com, A. Minahan (Volute) and K. Minahan (AbaKus). This article is used with permission and may be freely distributed on the internet, provided no editing is done, and this unaltered notice is included with the article. Click here to read more articles and to learn more about taking online courses in Witchcraft, Tarot or Herbs

 

Check out the new Gifts & Souvenirs Shop. This is a tiny gift shop with unusual items. This is also the new area where you can become a Member of PaganPath and save on Membership dues by signing up for more than one year.

If you prefer not to use the shopping cart system in the Gift Shop, you can simply click the key to join now for $35 for a full year. This includes enrollment in the PaganPath Academy and access to all courses and materials.