During the winter I became interested in a planting technique used to stimulate plants to grow extensive root systems. The benefits of this technique translate into stronger plants that are better able to utilize the nutrients in the soil they live in. The technique is known as root air pruning.
Root air pruning occurs in containers made out of materials that allow the roots to enter in contact with air once they reach the container walls. At such point of contact the tip of the root dehydrates and dies. However, the plant compensates by growing secondary roots in other directions inside the container. As these secondary roots further develop, and in turn come in contact with the container wall at a different spot, the process is repeated. The end result is a very well developed, very dense root system inside the container, as opposed to the single root that circles around and around and becomes pot bound inside a traditional container . There are many commercially available root air pruning containers, and perhaps just as many DIY suggestions available on line, (I particularly enjoy watching Larry Hall’s videos ).
Since this year I was using raised beds which limited the space we have available to grow vegetables, I decided to experiment growing zucchini in root air pruning containers, to gain the precious gardening real estate in the raised beds that would otherwise be occupied by the giant summer squash plants. I initially made four large containers (17 gal each) to house my zucchini seedlings. I made the containers by sewing heavy duty landscape fabric into a 16″X16″X16″ square-bottomed bags, which I then filled about 1/2 of the way up with the same soil (Mel’s Mix) I used in my raised beds.
Early enough it could be noted that the bags were doing a good job, the seedlings were growing strong and healthy with the extra heat they were getting in the dark containers. At that point I decided to try growing potatoes, so I made three more bags for that purpose, and I also made a long sausage like container which I planted with watercress seed, lettuce and celery.
I made a dozen 4gal bags, where I planted our squash, melon and water melon seed. The bags were great for starting seed because they could be closed at the top and provide a dark, warm and humid environment for germination while at the same time preventing squirrels and other critters from getting too curious and messing everything up.
To date, the 4 zucchini plants have produced almost 8lbs of food so far. We had some degree of success growing potatoes, and after emptying the bags we have already re purposed them to grow pumpkin, sweet potatoes and carrot.
These containers are so versatile, that I have also made 1/2 gal bags to root perennial herbs to share with friends, I am sure this size will also work great to start seedlings next spring. The bags are great for gardeners with limited land, for apartment dwellers with just a balcony, or even to use in areas that cannot be easily converted into gardens (patios, decks, lawns,etc). Next year I plan on expanding our bag farm to grow plants in a sunnier location of our yard, and to re-locate lettuce to a shadier area once the mercury starts climbing… the possibilities are endless.
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