Cedar Flakes For Mulching & Growing

 

Back in the early seventies, a gardening friend suggested he and I form a company to promote and sell cedar flakes as a horticultural product. He knew of a mill in the Hill Country that was grinding old cedar stumps and steam cooking the small chips or flakes to get the cedar oil. The oil was being used in all types of aromatics and sold at a high price. The flakes were considered a by-product and could be purchased cheap. My friend was a real gardening enthusiast, always trying something new, and was growing some beautiful hanging baskets in all different ratios of cedar, some almost 100%. Other gardeners were using a more expensive medium, such as imported peat, and weren't doing any better. I too like to experiment with different growing media, but we decided that if we were going to become successful in business, we needed to know as much as possible about our product, and we also needed other people's experiences. We gave a lot of the cedar flakes to other gardeners and even took two big loads to Texas A&M University.

All our research showed that cedar flakes were a good bet as mulching material and a growing medium, so my partner and I began our business. As time went on, our business venture grew. More and more nurserymen were learning to use cedar flakes in their potting mixes to replace peat and bark which were much more costly. We were up to four delivery trucks and thinking of purchasing another when business started sliding. At first we thought the drop in business would only be temporary, but it passed that point. We got worried and started asking our lost customers what the problem was. We learned that a report had come out of Texas A&M saying that cedar had a growth retardant effect. We followed the lead back and learned a graduate student had used our two donated loads of cedar as a research project toward his doctorate. He wrote a 70-page dissertation on the cedar.

In his publication, he wrote that his "experience indicated the possible existence of plant inhibitors in cedar mulch." The student didn't say it definitely did-only that it was possible that cedar contained growth inhibitors. This hint of bad news traveled fast through the industry, and any grower having problems now had a scapegoat to blame failures on. Luckily, we didn't lose all our customers. The older, more experienced nurserymen kept using cedar with no problems. They said there was nothing wrong with the cedar, and that the people who had problems didn't understand carbon/ nitrogen ratios and nutrient tie-up. They also said that they didn't always get the same results with a given amount of fertilizer.

My partner and I decided to have testing done on the cedar flakes. After many tests and great expense, there were still no growth- inhibitors or toxins of any kind found in the cedar. In my amateur research, I too, at times got mixed results. There was possibly something strange about cedar that we hadn't yet discovered. I kept studying and studying over lab test results, and more than a year went by before I found the culprit. It was too obvious.

The dry weight of cedar flakes is around 190 pounds per cubic yard. Saturated 100 percent, it weighs up to 1,600 pounds per cubic yard. I did more testing. If I took dry cedar flakes and soaked them in a fertilizer solution until near saturation, I had an excellent product and all plants grew well. Even if I let the cedar flakes dry out before using them in a growing medium, the results were still excellent. But if the first moisture the cedar got was rain or tap water, the plants didn't grow as well. I had a hard time getting enough nutrients to the plants.

Cedar flakes have a high carbon-to-nitrogen ratio and the decomposing microorganisms use the carbon as an energy source. If the cedar was soaked with plain water, there were few other nutrients in the cedar. As a result, the microorganisms had to rob the nitrogen from the plant roots. If the cedar was soaked with a nutrient solution, there was plenty of nitrogen in the cedar for the microorganisms, so they didn't need to rob the plants.

Reading back through the graduate student's summary, I noticed that he said the leachates (what is washed away with thorough watering) contained the growth inhibitor. I remembered that we had given A&M two loads of cedar. The first was dry and dusty; the second load I took was soaking wet with rainwater. This difference could have affected his results. When he used the wet cedar in his growing tests, the fertilizer solutions he applied would have mostly leached on through without benefiting the plants. When he used dry cedar, the fertilizer would have been absorbed so that there was plenty of nutrients for both the plant and the microorganisms.

The student also may not have understood that the cedar flakes were thoroughly leached with steam to get the cedar oil. This process removed all other leachates as well. In his leaching tests, he just removed the very fine wood particles. Taking out the small particles slowed down the nutrient tie-up in the remaining material since the microorganisms decompose fine particles first. The finer particles are a better energy source. The micro organisms can consume them faster, which also means they will need more nitrogen and other nutrients faster. If there isn't enough nitrogen for both plants and microorganisms, the plants will suffer.

Once this carbon-to-nitrogen ratio decay principle was understood, I could use cedar anywhere with good and predictable results. I have grown tomatoes, potatoes, cabbage, and many other plants in pure cedar flakes, getting excellent growth and production. I have also found cedar to be the best product to use when heeling-in balled and burlapped and bare-root trees. Cedar is acid; it inhibits root rot; it is very slow to decay, and roots seem to love it.

The most spectacular thing grown in pure cedar flakes were sweet potatoes. I planted eight slips (sweet potato plants) in a raised bed that was 12 inches deep, 7'8" long, and 3'8" wide. This bed contained about one cubic yard of cedar to which I added one gallon of colloidal phosphate clay for mineral and six quarts of bat guano for nitrogen. After the fertilizers were well mixed into the flakes, I put in the plants and watered with a nutrient solution of two tablespoons fish emulsion, one tablespoon liquid seaweed, one tablespoon of feed-grade molasses, and one teaspoon of a biological product called Agri-Gro™ mixed into three gallons of water. After the plants were well established and growing, I used this mixture in two gallons of water every time I watered. I watered in the morning and drenched the whole plant every time.

The plants were beautiful and, except for a few grasshoppers, not a single pest, disease, or insect bothered them. I let the plants grow until frost was expected, then let the flakes dry in preparation for harvest. Sweet potatoes store much better if they are harvested dry.

The dry cedar was so loose I just pulled the potatoes out by hand without using a spade. The bed was almost solid potato. Some were three feet long; others were shorter but nearly six inches in diameter. There were more than 137 pounds of sweet potatoes dug from that single raised bed. That is the equivalent of 109 tons per acre-production farmers dream of.

A gardening friend to whom I gave some cedar planted potatoes in the pure flakes. One day while I was visiting, he pulled up a potato plant and picked some fist-size, pretty, and clean potatoes off the roots. He then put the plant back in the spot he'd pulled it from, pressed the moist cedar tight, and the plant continued to grow without ever wilting. This would be almost impossible in normal garden soil. If the plant didn't die, it would surely wilt and be sick for a long time. The cedar from which the plant was pulled was loose; no roots were torn, and each root-hair was clinging to a small cedar particle.

I used to buy a few bare-root pecan trees each year to plant on the farm. When they arrived from the shipper, I placed the roots in moist cedar flakes, and they kept well. One year I gave two trees to a neighbor, and he kept putting off transplanting them until the middle of June. When he came to get them, they were already sprouted out about four inches. I suggested he leave them until they went dormant again in the winter because seldom does a pecan survive bare-root transplanting in the middle of summer. He didn't want to wait, and when we pulled the trees out of the cedar we found a tremendous amount of new white root growth with a lot of small cedar particles clinging to them. I helped the neighbor plant the trees. Not only did they survive, like the potato plants, they didn't even wilt.

The cedar tree (actually it is a juniper, juniperus ashei) has a bad name as an invader and can become so thick it will completely smother good pastureland. Like any other tree, however, the cedar tree seeds don't sprout where there is a good sod cover, but only where it is thinned by heavy grazing. A lot of people will tell you that nothing grows under a cedar tree. They don't realize the thick shade and heavy mulch of cedar needles usually prevents other plants from getting started. That's why ranchers chop off the branches, not bothering to remove the stump. The stump won't resprout, and with the shading branches gone, the grass grows well in that spot because the decaying needles enrich and acidify the soil. These soil-building and acidifying qualities of the cedar actually make it a valuable plant in Nature. Because it can thrive in rocky limestone and drought conditions, you can really call it a pioneer plant.

This story of the juniper (misnamed cedar) again proves that everything-be it mineral, microbe, plant, or animal-is beneficial, and even necessary. We could understand the important contributions such plants make if we would first patiently study and not jump to conclusions and be so quick to condemn.

 

The Garden-Ville Method - Lessons in Nature