After viewing the Back To Eden film, we decided to use this approach on all our garden beds. We've found a few places to attain free wood mulch, and covered all of our beds with 3-4 inches of wood mulch. Our results were both good, bad and indifferent, as follows, and I will outline some of my questions/answers and my plan for 2014.
We watered much less. Most areas were watered about once a week. We watered each area for about 8 hours with an oscillating type overhead sprinkler. (In previous years we used soaker hoses on timers, and watered every 2-3 days. We found this effective, but after many repairs to broken/split soaker hoses and a lot of work setting up the systems, we thought we'd try something different.) This new system seemed to work quite well. I frequently checked the soil under the mulch, and it stayed quite moist.
Fewer weeds in the beds. Yahoo! We still had a lot of the bindweed coming up through the mulch, but that was about it, and they were quite easy to pull. I don't think there's any way to get rid of that stuff.
It looked nice. Ok, aesthetics are a nice touch.
And boy was this a headache. We had millions of SOWBUGS or PILLBUGS, ROLY-POLYS or whatever. The wood mulch atop the soil made a perfect environment for them to eat and reproduce. In the past, my research had indicated that sowbugs are not generally a problem to the vegetable garden, because they eat decayed matter, NOT the plants themselves. However, with a sowbug explosion, such as what I experienced, there can be too many sowbugs for the food available, and they will eat seedlings, particularly beans. It is possible that the addition of a large amount of un-decomposed wood mulch created a great habitat for the sowbugs to reproduce, but because the mulch was fresh, it wasn't good food for them. They can only digest decayed matter or young, small seedlings, so that's what they ate. That's my theory.
I lost many of my beans and peas. In many cases, they would sprout, only to be eaten very soon. One new variety I had planted, and was anxiously awaiting the sprouts to appear, only to find a couple of sprouts. I dug around, looking for the seeds in the ground, and the seeds were gone! The only bugs present were the sowbugs, and they were everywhere. A whole row of carrot seeds never sprouted--I'm not sure if it was because of sowbugs or something else. I was successful with carrots in another part of the garden where I didn't see as many sowbugs. The seedlings of all the other things I started indoors in soil blocks and transplanted to the garden were unaffected. (Whew!) Next year I just may sprout my beans and peas indoors also. It will be extra effort, but may make the difference between growing beans and not.
Another problem with the sowbugs is that I found them eating my ripe tomatoes, particularly the Burbank variety, which was quite short, with tomatoes closer to the ground. I would find tomatoes with holes in them and sowbugs inside. These buggers even climbed up the vines to reach the tomatoes--they did not remain in their soil habitat. I've read that the sowbugs may only take advantage of holes in the tomatoes left by other bugs, but I'm not sure. There had been some grasshoppers hopping around, and they may have opened a hole for the sowbugs; I just wasn't watching :) At one point, I thought that leaving the damaged tomatoes on the ground for the sowbugs to finish eating might act as a trap keep them off the good tomatoes on the plant, but that didn't seem to help. There were just too many of the buggers.
After I began to discover the problem, my research indicated that two organic products can be helpful: diatomaceous earth, and Sluggo Plus. Unfortunately, for my garden it was too little, too late. I got these bugs under control somewhat, but not enough. Most sources recommend removing all mulch to avoid the sowbug problem, but I am unwilling to do that. I am determined to lick this problem in 2014. My plan of attack is listed below.
Another minor problem with the mulching was the presence of a few fungi. The ones I found and identified were considered harmless; a variety of mushrooms, bird nest fungi, and something else I never identified.
There are some questions regarding deep mulching I've found few answers for.
Q. How do add compost and/or manure to the garden? Is it necessary? (I continually make compost and we have plenty of horse manure to use up.)
A. Some sources suggest compost and/or manure are not needed with deep mulching. Some suggest mixing it in, others suggest sprinkling it on top and let the nutrients trickle down. Apparently adding manure will help the wood mulch decompose more quickly and add more nitrogen to the soil, which is being used up by the wood mulch.
Q. What do I do in the fall, to clean up and prepare for the next spring season?
A. Some say pull out the dead plants and do nothing but add more mulch if needed. For the most part, I have not found answers to this question.
Q. Does wood mulch make the soil too acidic?
A. Some sources would say yes, other suggest it isn't a problem. My best guess is that because our Colorado soil is generally quite alkaline, it won't be a problem. I'm not sure about the highly amended soil in our raised beds, and my pH tester doesn't seem to work all that well, but I'm not going to worry about it.
PREPARATION FOR 2014
Here's what I did, based on my best guess after research. After removing all garden debris and weeds from the beds, I raked back the wood mulch, then loosened the soil a bit with a hula hoe, which removed as many remaining weeds as possible. I added about an inch of aged horse manure and blended it in with the hula hoe. (Some of the 2013 wood mulch was also blended in during this process.) I sprinkled on some diatomaceous earth (DE) to kill off any remaining sowbugs before they overwinter in the soil. I raked back the wood mulch, then sprinkled more aged manure on top. Then we topped the beds with a couple of inches of fresh wood mulch. I'm hoping that the addition of manure will offset the problem of nitrogen being taken from the soil due to the wood mulch. I am hopeful that the deep freeze we have experienced in the past week (down to -18 one morning, and other sub-zero temps for several days) will have killed off some of the overwintering bugs.
To proactively control the sowbugs, I plan to rake back the wood mulch when there will be a week or so of dry weather* and sprinkle on some DE and Sluggo Plus, then replace the wood mulch, all before planting. I want to kill off as many sowbugs as possible before planting. I may also add some organic fertilizer (HOF) during this process.
*Both of these products become ineffective when wet. That is a big problem with them!
All in all, I think that the deep mulching system has been a positive change, and will create better soil for future years. I am currently reading Ruth Stout's "No-Work Garden Book" to learn more about mulching in the garden. We will continue deep mulching!