In this instructable I will cover the design elements, construction, installation and maintenence of two raised planter boxes I built for my vegetable garden. The two boxes are identical, with the small exception of the vertical trelises on each one for growing vining species such as peas, watermelon, pumpkin and cucumber.
The dimensions of each planter are 4 feet by 8 feet by 11 3/4 inches deep. The specific width and length is important, as these planters were built in order to employ the "Square Foot Gardening" method, which is supposed to conserve space, water, seeds and effort. the 4 by 8 foot dimensions also allow the planters to be built with minimal material wastage using nominal sized lumber.
The planters are built out of redwood cedar lumber. Cedar is very expensive (materials cost about $130 per planter) but it is naturally resistant to rot, termites and damage from sunlight. It's also very beautiful wood and a pleasure to work with because it's so soft. As an added bonus, sawing and drilling cedar fills your workspace with a pleasing aroma.
I tried to provide enough detail on methods and techniques that anybody should be able to build these and do a professional looking job; even if you're a beginner.
Please read on to find out how you too can build these planters.
Step 1: Some Notes About Choosing Materials
In order to build planter boxes identical to these you have three main options about which type of wood to use. Each of these types of materials have their advantages and disadvantages.
Standard Spruce/Pine/Fir Lumber:
This is just your standard everyday lumber that is untreated. This material is by far the cheapest way to build the planters (about 1/4 the price of cedar) but it will be vulnerable to rot, termites and damage from sunlight. Within a few months, the planters will turn an ugly grey color and may even warp and twist from exposure to sunlight. Even though they may be ugly, they will still remain strong and sturdy for many years, and you could always paint them to protect them from the elements.
Pressure Treated Lumber:
This is standard lumber that has been treated with special chemicals that prevent it from rotting. It's moderately expensive (about twice the price of SPF and half the price of cedar) but it's supposed to last for up to 25 years without rotting. The main downside to this material is that there is the widespread belief that the chemicals from the treated wood will leech into the soil and end up in your vegetables. I'm not sure if this is true but I will say that plant roots are supposed to have structures that prevent toxins from entering the plant, and I've been told about university studies that conclude that vegetables grown in pressure treated planters don't contain chemicals from the wood. You'll have to do the research and decide for yourself. However, pressure treated planters should definately be good for flowers and other things you're not going to eat.
This is by far the most expensive at about four times the price of SPF and twice the price of pressure treated. However you get the best of both worlds because you know that the wood isn't going to rot and you know that there's no nasty chemicals in your food. It's also the most visually pleasing option, and since my backyard is visible to most of the neighborhood, I decided on this option.