More Information on Using Plastic Organic Mulch in the Garden

Organic gardener Tom Doyle disagrees with F.P. Hughes use of 1 1/2 mil sheets of black polyethylene plastic mulch suggesting heavy 6 mil sheets instead when gardening.
September/October 1971
http://www.motherearthnews.com/homesteading-and-livestock/more-organic-mulch-information-zmaz71sozgoe.aspx




Tom Doyle, over in Indiana, also uses plastic mulch ... but he doesn't recommend the 1 1/2 mil poly that F.P Hughes uses.  

Without once touching a hoe or plow, you can harvest up to twice as much produce earlier in the season than you'll ever take from a cultivated garden. This may sound unreal if you're used to plowing and weeding but once you've tried gardening without cultivation you'll probably bid the hoe and garden tractor farewell forever.

Although you will have to prepare the soil for your vegetable patch the first year you try this method, all you'll do for the next ten to twenty years is plant seeds or seedlings in already-made holes using organic mulch and reap the abundant crop that gets better and better each year.

How can you accomplish so much with so little work? By using sheets of 6-mil or heavier black plastic to create your own tropical growing conditions under a lasting, fool-proof mulch. Your plants will grow through holes cut in the plastic and the weeds that usually flourish between rows will be smothered by the film. There's virtually no weeding with this method.

Plants grown this way are bigger and mature earlier because the plastic lengthens their growing season. Usually, in the chilly spring of northern climates, the earth is warmed by the sun's heat in the daytime only to cool again at night. The six mil polyethylene mulch holds that heat in the ground overnight, making it possible for the plants to grow 24 hours a day and 30 extra days each year.

The plastic also draws moisture from deep in the ground to the earth's surface during the day, where it condenses at night. This gives your plants moisture at all times and creates a near-tropical condition under the film, making the soil increasingly rich and moist.

When you prepare your garden the first year (actually, for the next ten or twenty) this way, select a well-drained spot where no water runs over the ground except for what falls on it. If the area is low or flat, dig a drainage ditch to take care of the overflow. Rich, loose soil is preferred but not necessary.

Plow the garden as you would any other, then spread fertilizer. Since there's only one plant to every two and a half square feet, you won't need much and — for the next ten to twenty years — you won't need any at all. Finally, harrow or otherwise prepare the seedbed.

Now lay a sheet of 6-mil plastic over the garden. Dig a trench about six inches deep and six inches wide around the poly, roll the edges into the trench and cover them with dirt to hold the sheet in place.

It's better to spread the plastic when it's hot. If you put it down cold, it'll wrinkle when it gets warm (although the wrinkles don't hurt anything). If the poly doesn't lie flat, put a wooden boardwalk down crossways every 20 feet or use some sand here and there.

The rows of holes that you cut into the plastic should be 30 inches apart so that one row of plants reaches another to make a solid garden of vegetation. This shades the polyethylene during the hot hours of summer and helps hold heat during the nights. You'll find that the plastic lasts longer, too, if it's partially protected from the sun this way.

Within the rows, the holes for plants and seeds should be made one foot apart, beginning two feet in from the edge of each sheet. Skip the holes that you don't need for plants that require more room and cut out strips four inches wide between every other hole for radishes, beets, carrots and other plants that grow close together.

Once it's laid and the holes are cut, this heavy plastic mulch can stay put for ten to twenty years . . . cutting your work to almost nothing. You will have to take a few precautions with the poly, though, and modify some of your planting techniques slightly: 

  • Don't use cheap or clear plastic that lasts only one or two years. Use heavy 6-mil black poly with a ten-to-twenty year life.
  • Wear flat heels when you walk on the plastic.
  • Don't let animals walk on the polyethylene.
  • Record your planting schedule this year. It will help you plan your garden in years to come.
  • Plant corn one grain to the hill.
  • Plant potatoes and sweet potatoes on the end of the garden where you can cut off their tops and roll back the plastic when it's time to dig them.
  • Plant peas early with five or six seeds to the hill.
  • Plant two beans to a hill.
  • Plant tomatoes three to four feet apart.
  • Plant melons two seeds to a hill and thin to one plant per hill, three to four feet apart.
  • Plant lettuce several seeds to a hill and harvest the largest plants first to give the smaller ones a chance.
  • If you plant strawberries, use everbearing varieties and cover them with straw-in the fall.
  • When a plant has fulfilled its usefulness, pull it up and plant something else in its place.
  • Be sure to plant a row or two of flowers.
  • Clear off the plastic in the fall in preparation for next year's garden.