Building Door Step Garden Bags
Our project gardens started with burlap bags in California (we get ours from the local coffee roaster). In Kenya we are using both burlap and woven plastic bags (used maize sacks from the local miller in Kiandutu--cost about 25 cents each). The bags can be used either vertically or horizontally (lying flat).
Why burlap? It's free or very cheap. The burlap bag decomposes, so there is no waste. After a year, you empty the soil, freshen it with fertilizer and put it in a new bag. Burlap drains-unlike tubs, tires, solid plastic bags or just trying to grow things in the dirt. In Kenya, we are using woven plastic bags from local flour mill because they are cheap, available, and may last up to three years.
If you use the bags vertically- it's nice to have a wire support structure (see pictures in handbook). A wire structure provides a natural trellis for tomatoes, peas, and beans, and it helps prolong the time the bag can be used. We use the heavy gage wire mesh designed to underlay concrete (openings are about 4" square--available in the cement section of local home improvement centers). A piece can cost $5-10 and it will last for years. But you do not need a wire support. If you are building vertical potato sack gardens-or a low height vertical garden-no wire is needed. With potatoes, you start with a low bag and keep adding dirt as the plant leaves emerge, rolling the bag higher as you go. You "hill it" in the bag.
If building a vertical garden, you will probably need to insert a drain, especially if the bag is tall. Our first bag used a French drain extending the entire length of the bag. You could also saw off a French drain to go just halfway down the bag. We've also made drainage cores using a plastic soda or water bottle. If using a bottle, cut lots of holes in it so the water can drain out. If using either a French drain or a soda bottle, fill it with medium to small rocks. At our gardens in Kenya, we're using mostly soda and water bottles-although, we also built some with just a stone column down the center. Basically, we are re-using trash to make gardens.
The tools needed to make the bags are simple-shovels, a wire cutter and pliers if making wire cages, and a tray or wheelbarrow to haul and to mix the soil and manure. You'll also need a knife or sharp stick to cut openings and a hand shovel for planting. In Kenya, we supply the expensive stuff to the centers-like the shovels, wheelbarrow, wire cutters.
For the soil, in the U.S., I use a mix of available soil, potting soil or a bag mix or garden soil from the garden center. I mix the soil 3 to 1 with compost/manure. Manure mix is steer and chicken-in a 3-1 ratio. We use this because manure is available in the communities where we work. One bag takes around 3 cubic feet of amended soil. Or 3 bags can be made per cubic meter. You may want to consider adding perlite or vermiculite for moisture retention, and gypsum, bone meal or crushed oyster shells for calcium.
Once you have the basic materials, building the bags is simple. For vertical bags, first load a layer of gravel at the bottom (optional), then add some soil, then insert the drain. Add the rest of the soil around the drain. Water the soil, cut holes, and then plant starts or seeds. In Kenya, each bag is placed in an 8-inch deep hole to help hold it, then the bag is filled with soil and a center core of stones for drainage. When the bag is finished, the builders dig a donut of soil around the bag and amend that soil with manure to create a richer growing environment at the base. Obviously, this would work here in the U.S. as well.
For horizontal bags, load the soil mix and seal the open end with clips or wire or fold the open flap under the bag. Cut holes, water the holes well and plant. There's no need for gravel or for a drain. The horizontal bag creates a nice raised bed with good drainage and well amended soil. The downside is that it takes up twice as much space as a vertical bag, and grows fewer plants.
In our first bag, we put in a full-length French drain filled with rocks and used plant starts and pea seeds. This worked great-see picture. The watering was done on the soil, not in the drain.
Our next bags used soda bottle drains, and seeds. These worked great, too. You water both the soil and in the soda bottle. If you plant with seeds instead of starts, you must use a spray bottle on the seeded areas every day for the first couple of weeks to ensure germination. We also have started to use 10-12 inch French drain pipes loaded with gravel-these work great as well. The drains help carry the water to lower levels where the side plants are located.
I have gardened for 25 years, and I have never been able to grow so much food in a space only 18 inches in diameter. The advantages of bag gardens are many: easy set up, no conditioning of hard or polluted ground, no digging deep beds, and no need to build expensive raised beds for gratifying results. Burlap also keeps weeds to a minimum.
Plants we are growing include kale, chard, spinach, peas, mustard, squash, tomatoes, and pumpkin. We picked these plants because they are highly nutritious (see the handbook for the chart with nutritional values).
Some of you may want to try bag gardens for yourself. If so, let us know how it turns out. You can click on the link below for a handbook with more instructions. For more information on Door Step Gardens contact John Olson firstname.lastname@example.org