My wife and I like to research interests and talk about implementing them which
lets us discuss pro's and con's to the idea. I read several articles on
the interwebs about building your own raised beds and the benefits, she
did the same. After a long time coming we decided we had the time,
reason and know how to make it happen. We decided a variation of square
foot gardening was the first inclination. The second was that choosing
to assemble with organic vegetables that were non-GMO and materials that
would not leech harmful chemicals into our soil. 
I'll start the how to first with some disclaimers because an experts we are not. This is not a definitive do this, merely a how to do it like I did. This is a trial and error, then learn and adapt process for us. We have not had much experience in gardening, just three gardens, and they have not lived up to our standards or met our munching needs. This whole undertaking is the culmination of the learning process to date. We are hoping that the adjustments that we made such as selecting our soil combination and making the beds with ease of access will help set this years adventure in the right direction for a more profitable situation in every way possible.
The first thing I did was to realize that I already owned enough plywood to encase the bottoms of my garden boxes and enough 2x4's (non treated) to build a small four foot square box.This made things pretty motivating. We had planned to build three raised bed gardens, two four foot square boxes and one ten foot long four feet wide. The articles that my wife and I came across helped us ascertain that for ease of planting, watering and weeding the boxes should be no larger than four feet wide. This is a take from square foot gardening.
I used untreated wood and nails and screws that were not treated with zinc. For ease I was able to have the hardware store cut my boards that were used for the perimeter walls to length, I had to handle the plywood base myself with my trusty, beat up, hand me down saw. While I was at the hardware store I purchased my fasteners and twine. I nailed the boards together with an end overlapping, in order to avoid crazy angle cuts on the corner and for ease of fastening, and repeated the process in the same direction until I had the perimeter completed. Once this was completed I nailed the plywood (fantastically cut by myself) onto the bottom of the perimeter. This is what will hold the shape of the garden boxes and contain the soil and also act as an informal barrier from pests such as leaf eating bugs and weeds. Once this was done I placed them in position on our small deck in a place that receives six to eight hours of sun everyday. After this I called my wife to join my side and admire my handiness...and day dream together about what we will plant and how awesome it will be to walk out the back door and grab some ingredients for dinner.
This mini victory prompted us to visit one our favorite family destinations Tuttle Orchards! We love this little orchard just outside of mainstream in the fall when the apples are ripe for picking. On our small vacations from the real world here we like to visit the farm store for bee pollen and Amish vegetables but for this visit we intended to visit the greenhouse. This business is local and our mutual assessment is that this orchard takes a natural approach to their commodities. The plants that we chose were part whimsy and part knowledge from research. The greenhouse is where we will purchase the already in the process of growing plants. This is a lesson that we learned from past gardens. We like the instant gratification of not waiting for the seeds to turn into plants, we also find it much less tasking on our busy life. My wife and I chose several varieties of vegetables tomatoes, eggplant, peppers, squash, zucchini, melon, peas, lettuce and also some herbs mint, basil, oregano, chives, cilantro and we also planned to plant seeds of carrots, beets and corn, onions should probably be mentioned here as a seed. A convenience to visiting this local business was that we were also able to purchase our soil here as well which was three equal parts of peat moss, composted manure and top soil with no chemicals added.
On our return to home we discussed things like marking off our garden boxes by square feet with the twine I had purchased at the local hardware store and some screws that I would place every foot along the perimeter of each garden box. Once again the conversation ended with daydreams of slicing up fresh food. We really enjoy food we can trace the roots of where it came from. (pun intended)
I equally mixed the three part soil and then my wife and I placed the
twine on the perimeters of our three garden boxes. This process was
relatively simple with a rake and some good conversation. I watered the
soil after mixing to ensure it stayed in place and make planting a
breeze. When planting we took special attention to place plants in a
location that would not block others from receiving the proper amount of
sunshine. Our research into SFG (square foot gardening) told us that
plants needing twelve inch spacing would require a full square such as
tomatoes, squash and melon. The smaller plants that need two to four
inch spacing could handle up to sixteen plants in one square such as
carrots and onions. Our peas and Brussels sprouts would only support two
to four plants per square. We claimed another small victory on the day.
The positive situation was shared by the whole family, mostly my wife
and I. The garden received a drink to promote plant acceptance of their
new homes, we enjoyed a frosty glass complete with refreshing liquid
and shared accomplishment for our so far 'meeting the standard' garden.
Some notes on the learn and adapt. I needed a support for plants. I found a pre-made lattice support at the store but it was more cost efficient for me to buy some loose lattice and a staple gun and customize it on my own. I was happy with this decision. (see third pic) Buying the materials for my melon and cucumber supports made it easy for me to affix to the sides of my perimeter boards and enables me to add on if needed. I also caged my tomatoes with a perimeter cage and strung twine from side to side of the perimeter to aid in supporting the limbs. In building the garden boxes I used three different sizes of perimeter boards. For one 4x4 garden box I used 2x4 which was a little too shallow for more substantial root bases, we planted lettuce and herbs in this one. This will limit planting in the future and would not be a sustain for me. The long bed was constructed with 2x8 which is very sturdy. This one is sufficient for more substantial root based plants and is an acceptable method, we are pleased with the turnout of this choice. As another option for a 4x4 garden box we used 1x10 boards. The depth of this box is acceptable for any plant which is a sustain. A not so great feature of this size board is that being thinner allowed bowing after fastening and needed screws to reinforce and ensure it would stay together. Below are a few websites to check out for tips:
Square foot Gardening
Organic gardening explanation
Food Inc. watch it!
