Grober Green

by Larry McCuaig

When I retired last year, I acquired a small property near Kemptville with about half an acre of grass. When I took soil samples I found that about two thirds of the proposed growing area consisted of a thin layer of topsoil (two inches) over stony fill. The previous owner had done this to level off the yard. The other one third contained a thick layer of sandy loam over deep sand.

Since I was already limited in growing space, I decided to find a way of growing crops without soil. My problem turned out to be fortuitous, since my goal is to improve poor soils of all types with natural, practical means.

I decided in favour of the strawbale system after reading an article in Organic Gardening which showed how, by using bales to grow plants in, problems of soil-borne diseases and insects can be avoided (as well as avoiding weeding and cultivating).

From my work with Seeds of Hope and the Y2K Regional Preparedness Group, I realized the value of the strawbale system to anyone who wants to grow vegetables, but has little or no soil, or very little space. The bale system is ideal for them because it can even be used on a balcony.

The System

The use of strawbales for greenhouse growing apparently has a long history and has been practiced in many countries. I found a lot of technical information in an Agriculture Canada Publication on greenhouse growing. I adapted the greenhouse chemical-based system to an outdoor all-organic one.

The main advantage of the bale system, aside from not requiring soil or much space, is that it provides copious amounts of air, water, heat and slow release nutrition to the plant roots. Therefore it should be most useful with heavy feeding crops, especially those that love lots of organic matter and warmth, such as cucumbers, pumpkins, melons, and tomatoes. These are the main crops I am growing, though I am testing it out on peppers and potatoes.

Disadvantages include an extended preparation period for the bales—wetting them and activating the breakdown process. It is also necessary to incorporate a slow release fertilizer, or use a liquid feed throughout the growing season—or both. I decided on liquid feeding, with compost/manure extract, which is less expensive and more readily available than solid fertilizers such as bone and blood meal. Backyard or balcony gardeners may not want to use manure extract, so they might prefer a commercial organic fertilizer.

I am using 30 bales, ten of wheat straw and 20 of barley straw, so I can compare them. Wheat straw is much denser than barley, holds a greater amount of water and breaks down a lot slower. Barley, on the other hand, has greater air space and turns to compost much sooner.

The Procedure (for all bale and crop types)

After daytime temperatures are above 10 degrees C, place bales in growing location and begin watering them at least twice a day for three days or until they stay wet inside (this starts the fermentation process).

When bales are thoroughly wet, add a little fertilizer (soak with dilute manure or compost juice or bury solid fertilizer in holes in the bale). If possible, calculate the amount of fertilizer equivalent to 50 grams of Nitrogen per bale.

Check the temperature of each bale over the next week or so. It should rise to 50-60 degrees C (uncomfortably hot when you stick your hand in the bale). Keep the bales from drying out by adding a little water each day—not enough to leach out the fertilizer.

Let the bales cool down below 35 degrees and soak thoroughly with a hose to leach out any excess salts. If the bales are not off the ground, you may want to have a plastic sheet under them so you can catch the run-off and recycle it through the bales.

Plant seeds or transplants (better) in 1 to 4 holes in each bale (depending on the rooting space needed by your plants), along with a goodly amount of growing mix, compost or sterilized topsoil. If the bale has not softened up sufficiently to pull material out with your hands, use a keyhole saw or serrated knife to make the holes.

Water the plants as needed (pumpkins and cucumbers will need daily watering at the peak of their growing cycle) and fertilize periodically by top-dressing with solid, or watering-in the liquid, materials.

Note: I produced a variety of liquid feeds for my system, using well-rotted cow, horse or chicken manure, or composts made from fish waste and peat moss. I added these to 50 gallon plastic barrels, which I then filled with water at a rate of five gallons of compost to 45 gallons of water. The chicken manure has the highest Nitrogen content, so care must be used in its application to prevent development of “legginess” in young plants.

As of early June, all my bale plants are growing nicely and I do not have to do any weeding or cultivating. I just mow the grass around and between the bales.

And unlike my backyard garden here in Ottawa, where the cutworms have decimated my Brassicas and earwigs come out of the ground at night to gobble up my young cantaloupe plants, there is no sign of any insect damage in the straw bale garden.