Mulch

Mulch serves many practical and ecological purposes in the garden.  For the lazy gardener or farmer, it is a means to cut back on weeding and watering chores.  Various mulch materials function in different ways.  Most mulches serve to preserve soil moisture by creating a buffer to limit evapotranspiration.  Mulches cover the soil surface, thus making a physical barrier to prevent weed growth that blocks out the sun.

Farmers often make use of black plastic mulch, a layer of black plastic secured over a row or bed.  For crops, holes are poked in the plastic and transplants or seeds are planted in.  Black plastic also absorbs the heat from the sun thus warming the soil it covers.  This mechanism can allow for earlier plantings of summer crops that require warm soil temperatures.  Black plastic can be preserved for up to a few seasons if treated super minimally, but, regardless of its life time, it is an inorganic material that ends up being pulled up and sent to the landfill.  Of course there are means for creative recycling of inorganic materials, but solarized black plastic is a nasty material that when pulled up often breaks apart into pieces.

The optimal mulch materials are those that are organic and can be broken down and used by soil organisms as food.  These materials include leaves, straw, hay, wood chips, compost, cardboard, newspaper, dried grass clippings and garden prunings, chopped up twigs, etc.  Utilizing organic mulch materials serves multiple purposes beyond those of inorganic materials as the mulch becomes a means for improving soil quality, soil structure and soil biology.  This, in turn, aids the growth and well-being of the crops grown where organic mulches are used. 

At our farm, Bottle Gourd Herbs at Historic Penn Farm, we utilize various organic mulch materials and methods.  Here we will share some images along with information about the organic mulches at work:

Pictured here is one of our hay-mulched keyhole planting beds.  The mulch layer is about 3-4 inches thick.  The bed was planted to bush beans, beets and calendula almost three weeks ago.  The only seedlings coming through are those of our crops.  At first there were stray pigweed or thistle that popped through but when picked out early that's about it for weeding in a thickly mulched bed.  

The cardboard you see (which is dry here - after rain all the ends flatten down) is one of the mulch methods we use to outcompete the grass in the pathways.  You can see to the left edge and in the yet un-mulched areas the thick grass.  Waste cardboard is a low-energy method for managing unwanted grass, particularly when compared to the continual mowing often used in row farming.  

    

When establishing transplants on cleared land, a hefty hay mulch ring around the seedling will prevent immediate competitors.  Be sure to leave a couple inches all around the stems of the transplants, like done for the pumpkin pictured here, to allow breathing room.  This pumpkin species is a Japanese kikuza (thanks, Shelby!)

Another mulching method is to thickly sow cover crops that will outcompete other weeds/grass.  Pictured here is dutch white clover sown in the path adjacent to a hay-mulched keyhole bed.  The clover was sown a little too late to outcompete most of the weeds, but you can get an idea of its function.  White clover is perennial and will come back next year after reseeding itself too.  We will see how it comes in next spring and overseed too.  Many farmers and home gardeners grow the low-growing dutch white clover right in their beds under crops like squashes, tomatoes, peppers, etc.  We will be doing the same in our large section of field planted entirely to vine crops.

Pictured here is a close up shot of our first radish bed, a trial bed for thickly sown, barely mulched growing beds.  Not only did grasses do a good job of inhabiting the bed, but some of the straw was not totally rotted and about a 1/3 of the grass you see here is wheat!  Nonetheless, the radishes grew beautifully, with robust leaves and distinct fine flavor to the root.  This can be owed in part to the ability of weeds or thickly planted vegetation to serve as a mulch.  The soil was also dug in with equal parts compost and fertilized with bio-active mineral meal.    

We sure love mulch and mulching.  If you have any questions about using organic mulches, please write to us at info@depermaculture.com  Feel free to leave a comment about your experiences with mulch materials, we'd be delighted to hear from you!