Interbay Mulch

As an over-winter method for building humus-richsoil, it would be difficult to improve on the "Interbay Mulch" (named after the P-Patch where it was developed) for effectiveness. Interbay-Mulched soil, according to lab tests, is "uniquely active". Over a winter, an Interbay Mulch will give you a large volume of humus as well as a rich diversity of bacteria, fungi, protozoa, beneficial nematodes, arthropods, and worms.

Interbay Mulch is basically various organic matter culled from the urban waste stream piled on top of your soil and covered with damp burlap. Organic matter decomposes faster on top of the soil than it does when tilled into the soil as long as it is covered and kept moist. 

 Covering organic matter with burlap fools nocturnal, light-avoiding organisms into working for you 24 hours a day. Burlap will diffuse and soakup rain preventing it from driving into the mulch. It inhibits evaporation, keeping organic materials uniformly moist. Birds are unable to forage in the mulch so worms and other organisms flourish and multiply. Burlap covers the mulch but is also part of the habitat cultivating a rich variety of fungi and providing a home for beetles, spiders, worms and the like. Burlap is permeable allowing oxygen to reach all parts of the mulch. Every October the P-Patch program makes Burlap coffee bags available to gardeners at various distribution points.

Building the Mulch

The first materials used in an Interbay Mulch should come from your garden debris. The crops you raised took nutrients from the soil and now it time for them to be returned. Chop up your corn, bean, squash vines, tomato plants, etc. (Many experienced mulchers don't even worry about seeds because of ongoing top dressing mulches during the growing season making a weed free garden) If you are concerned about seeds or diseases hot compost those plants. Interbay Mulch uses the same "brown" and "green" mix used for hot composting, approximately 50-50.

The more variety in materials added to the mulch the better. Leaves are a brown that are easily obtained in the fall. Dried cornstalks and straw are good browns. Straw is even better if it is rotted. You can also add rotted burlap, cotton dryer lint, shredded paper, and season with a few pine needles. Woody material should be limited to rotted material that you can smoosh between your fingers.

Practically anything that doesn't burn when you put a match to it can be used as greens. Garden debris, green corn stalks, fresh grass clippings, coffee grounds (leave a bucket at your favorite espresso cart), juice bar pulp, spent grain and hops, seaweed, grape pressings, apple pressings, and so on. Any kind of organic manure is good.

Using compost as part of the mix will jumpstart the system. One wheelbarrow full of rough compost per hundred square feet is sufficient to get things going. Burlap from previous Interbay Mulch can also be used to inoculate your new mulch. The used sacks are full of dormant organisms just waiting to go to work.

Mix your greens, browns and compost starter to a depth of 6 to 18 inches deep. Make sure all materials are damp. Cover with burlap.

Maintaining the Mulch

Check the mulch for moisture during the winter. The burlap absorbs water and then quickly releases it to the cold and winds during the winter. Little moisture will find it’s way into your mulch. This feature also keeps the rains from compacting and leaching the soil. If materials dry out decomposition comes to a halt. You can alsofeed your mulch during the winter like a worm bin. Adding materials once the mulch is active makes it work even better. Checking your mulch out in the winter will give you a chance tocheck out the fascinating soil food web biology at work. The biology is fascinating. You will have given birth to billions of trillions of organisms. Some you can even see!

Spring Planting

If you start your mulch in October you should haverich humus to plant into by March. If you started with 12" of mulch you will end up with 2-3 inches of soil-energizing humus. You can till the mulch in or just plant right into it.