I have been an organic vegetable grower in the Campbellville area for about forty years. My garden is 2,000 sq. ft. of growing space. For the past several ears I have alternated sides [a path down the centre divides the area into two 1000 ft. spaces] with green manure in the non-growing side. I would like to cut down on my crawling around on hands and knees to plant, divide, and weed, and am interested in trying a raised bed or two as an experiment . My husband can build them, but I am at a loss as to how high to go, most specifically. Other concerns might be best wood to use, lining or screening on bottom, etc. I am very intrigued by the Hugelculture method, but wonder if straw bales in the bottom would be an acceptable alternative to logs? I am planning on 3 ft. by 10 ft. for the width and length of each bed, at the moment. Has anyone had experience with raised beds other than the very low ones? I would appreciate any helpful advice.
How exciting to be considering new gardening techniques after so many years! After 40 years I can understand why you want to stop crawling around in the garden! Both traditional raised beds and hugel beds will provide more comfortable and accessible formats for your vegetable gardening.
I have been very pleased with raised beds that I made for my vegetable garden a few years ago. The frames are made of cedar logs, piled three logs high (about 14 inches). I can sit on the log frames to garden in the beds. In addition to being more comfortable I have appreciated that the beds are ready for gardening earlier in the spring and that because I never walk on the soil, it requires much less preparation before planting.
The height of frames of your beds is very much a matter of personal choice and how you intend to garden. If you plan on gardening by sitting on the edges of the beds, I suggest frames 1 to 1 1/2 feet high; alternatively if you plan on gardening from a standing position the frames could be several feet high. On making the frames of your beds you are not limited to wood as raised beds are often framed in a wide variety of materials , including bricks, concrete pavers, logs, lumber, railroad ties (untreated), and metal livestock water troughs.
If you are going to frame the beds with wood, cedar (either logs or lumber) is a good choice as it will last for many years without any chemical treatment. Redwood is an alternative choice for the same reason. You could also use pressure treated wood which has not been treated with chromated copper arsenate (CCA, as it contains arsenic which could seep into your soil), or recycled lumber. If using recycled lumber look for lumber made from a durable species such as cedar which is untreated and unpainted (again to prevent chemicals from the lumber’s finish from entering your gardening soil).
If you are planing on siting the beds where you have been growing vegetables for the last 40 years, it is not necessary to line the beds or use screening at the bottom as I expect there is already good drainage and you are not worried about root competition.
Here is a link to previous Toronto Master Gardener question on raised beds which you may find useful: http://www.torontomastergardeners.ca/askagardener/raised-beds/
I just recently heard about hugelkultur, which sounds very interesting as an alternative to the more traditional raised bed and whose use is rapidly spreading in the North American gardening community. (While I have not yet tried it, there is a pile of brush in my yard being kept for just purpose!) Although you could use straw bales as an alternative to wood in the construction of your hugel bed, the straw will breakdown much more quickly than wood, and required you to remake or add to your hugel bed sooner. It may also not retain water as well as a hugel bed made on a wood base. If you have limited access to wood logs, consider constructing the hugel bed out of a combination of logs, straw, sod, and woody clippings from your property. Here is a link to a site with information on the constructing of hugel beds, including those which are made out of a combination of wood and straw: