No-till garden beds save water and labor

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Last Updated: 
February 3, 2006

CORVALLIS, Ore. – One of the many advantages of living in the Pacific Northwest, at least west of the Cascades, has always been a plentiful supply of water. Full streams and reservoirs have usually allowed home gardeners to choose and cultivate plants without worrying too much about water requirements.

But even during the rainy season, we can't take the water supply for granted.

Once summer comes, the rain and snow diminishes and there is much less moisture during the warm half of the year. And some winters are dry. The winter of 2000-01 was the second driest on record. In the high desert, east of the Cascades, water is always scarcer.

Winter is a good time to consider and plan to reduce the amount of water you need for summer vegetable gardens. Consider trying the "no-dig" or "no-till" method of raised-bed gardening.

Barb Fick, community horticulturist with the Benton County office of the Oregon State University Extension Service, says she's kept her large vegetable garden by the no-dig method for years. Not only does it use less water, she says, it discourages weeds, improves the soil, and reduces labor for tilling and weeding.

The crux of no-till gardening is to pile on enough mulch to keep weeds from germinating and growing up through it. If you use leaves, grass clippings or straw, you might need as much as eight to 10 inches of mulch.

If you start out on the bare ground with something more solid, like cardboard or 10 sheets of newspaper, you'll need fewer inches of leaves or grass clippings on top, explained Fick.

Around bigger plants like melons, tomatoes, eggplants, and peppers you can even spread heavy black plastic for mulch, although you'll need to check it regularly. Depending on its weight, plastic sheeting eventually breaks up into tiny pieces as it deteriorates from exposure to the sun.

Fick says she piles on aged mint straw (compost) in the fall and leaves it on as mulch the following spring and summer.

"Whatever you use, don't skimp on mulch," said Fick.

A heavy layer of mulch not only keeps weeds from growing, it also keeps the underlying soil moist, greatly reducing the amount of watering you need in the summer.

Another advantage to "no-till" is that you don't turn over most of the soil in your garden. This prevents you from bringing old weed seeds up to the surface where the conditions are good for them to germinate – so you reduce the weed population even more.

To establish a new garden this way, start in the fall or winter by outlining your beds with landscaper's spray, the kind that is non-toxic and washes away with a little rain. Or use a garden hose or rope if the borders of the beds are curved. Give this step plenty of thought – if you keep this configuration permanently, or at least for a long time, the paths between your beds will be compacted by foot traffic, making them inhospitable for weeds.

Since you won't be tilling, you won't need to confine your garden design to straight lines and rectangles: curving lines are often more pleasing than straight ones. You might even want to incorporate some vegetable beds into your existing non-vegetable garden.

In any case, be sure to lay the vegetable beds out so that you can easily reach any part of the bed from a nearby path while kneeling. You'll want to avoid stepping into the bed and compacting the soil.

If you put your new no-till garden into an existing lawn area and want the paths to remain lawn, don't forget to make them wide enough for your lawn mower.

When you're ready to plant in the spring, push the mulch layer aside just where you want to put your seeds or starts. For the first year or so, you may need to dig out old roots and add a little topsoil or compost in the hole where you want to plant.

Over time, the mulch layers you keep adding will form enough soil to support your garden. And the soil formed by the addition of so much organic matter will likely be loose, full of earthworms, and teeming with the healthy microbes that make nutrients available to your plants.

When one of your crops is finished, incorporate the dead vegetation into the mulch.

The best way to water a no-till garden is with soaker hoses and/or drip irrigation, further cutting water waste.

If the prospect of a vegetable garden blanketed under huge mounds of mulch doesn't fit your vision of a perfectly tended garden, Fick recommends remembering what the reality usually is out in your garden – soil baking in the sun and plants pathetically turning gray as they head toward dehydration.

Author: Davi Richards
Source: Barb Fick