Nontraditional gardening: Square foot

Part one in a three-part series 

Chisago County Master Gardener Mark Stuart tends to his square foot garden. Photo by Derrick Knutson

Chisago County Master Gardener Mark Stuart tends to his square foot garden.
Photo by Derrick Knutson

Those who have stopped by Sunrise River School or Fairview Clinic in North Branch recently have likely noticed the tidy-looking gardens on the properties outside the buildings.

If looked at from far away, one might mistake them for average raised bed gardens, but upon closer inspection it’s evident they are different: The healthy-looking produce grown in these gardens is sectioned off in neat, 1-by-1-foot squares.

Chisago County Master Gardener Mark Stuart offered his expertise to help build these gardens in the spring.

He has numerous square foot gardens outside his home near Stark.

Stuart said he got the “square foot gardening bug” about three years ago after reading about the technique, and now it’s his favorite way to garden.

How to make a square foot garden

He explained how the gardens are constructed, noting it takes about three hours to do one garden box.

“Basically, what we do is we make these boxes, which are made out of 2x6s, and then we put (landscaping fabric) on the bottom, and then we fill it with our own mix,” he said. “The mix is made of three things: peat moss, vermiculite and compost. The idea is that it’s the optimal growing medium for plants.”

To fill the beds, the mix should be one-third of each component.

Stuart takes the compost aspect of the mix further than some gardeners might. He said the way to get the most nutrient-rich mix is to get different kinds of compost from various suppliers.

He said buying commercial compost, a bag of composted forest products and another type, such as manure, is a good way to establish a broad nutrient profile.

Stuart said a good way to get the product thoroughly mixed is to spread it out on a tarp and have a few people pick up the tarp, fold in the corners so the mix doesn’t spill, and then roll it back and forth a few times.

After the beds are constructed and filled, all one has to do is measure off and mark 1-foot intervals on the sides of the 4×4-foot box to make a grid. The grid can then be divided with numerous materials, including twine or nylon attached to screws. Some gardeners prefer having thin strips of wood screwed to the edges of the box to make the grid.

Stuart recently built three more square foot gardens on his property, and the total cost to construct and fill them was $120.

He said non-treated wood should be used, noting he uses the slightly more expensive cedar, which lasts longer.

Stuart said the boxes should last about 10 years, as does the soil, which he occasionally tops off with a little compost when he plants new crops.

Benefits of square foot gardening

Stuart said the advantages to square-foot gardening are many faceted.

“The idea behind square foot gardening is that there is no rototilling; you don’t have to do any digging,” he said.

He also noted the gardens have substantially less weeds than the traditional form of gardening where plants are grown in rows in the soil of a yard.

“Our soil has no weeds in it to begin with,” he said.

Stuart noted the gardens need to be weeded from time to time — wind can blow weed seeds into the garden or birds can drop them there — but that process is easy compared to weeding a traditional garden because the soil mix in the square foot gardens is so loose.

“It’s not like pulling weeds out of hard-packed clay,” he said.

Overwatering a square foot garden also isn’t an issue, Stuart explained, because the mixture can only soak up a certain amount of moisture before it won’t let in anymore; excess water just runs out of the bottom of the box.

Watering is a cinch, too. Stuart said there isn’t measuring required.

“If they look dry, I water them,” he said, adding that he waters one square at a time with a watering can.

Stuart said one square foot garden would grow enough produce for one person to have salads all summer long, and they’re space efficient with high yields, which is great for people who don’t have a lot of yard in which to garden.

Stuart hangs frost guard fabric from this tubing to get a couple extra weeks of growing in the fall.  Photo by Derrick Knutson

Stuart hangs frost guard fabric from this tubing to get a couple extra weeks of growing in the fall.
Photo by Derrick Knutson

He added that he extends the growing season with some of his square foot gardens by running piping along the edges and overtop, from which he hangs frost guard fabric. That usually gives him another couple of weeks in the fall for growing.

For more information about square foot gardening, look for books by Mel Bartholomew, the founder of square foot gardening, or call the University of Minnesota Extension Office in North Branch at 651-277-0151.

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