Part 5: materials
You want raised garden beds no matter what. The most proficient and abundant market gardeners (the small farms at your farmer’s market) almost certainly use raised beds that are a “standard” 100 feet long by 30 inches wide (they just don’t use wood to frame them in). This method allows for intensive production of vegetables. It also will get you past almost all of the soil problems you are going to have in northern Virginia.
You can use some of the soil that is already in your yard by working in lots and lots of organic material (compost), but it’s a lot harder to do this and for simplicity I would recommend you just haul in all your growing dirt (maybe later I’ll write an article describing how to use native soil).
You are going to have to make some type of wooden rectangle or square to hold the sides of the raised beds. I really mean this… you are going to have to make them yourself. The cedar garden bed kits are expensive and the ones I’ve seen are made with ¾ inch thick wood; even though it's cedar it definitely will not last as long at the 1.5 inch or 3.5 inch thick pine/douglas fir I recommend below. Just don’t buy the kit. And if you are worried that you’re not good enough at building also remember that you are building a square or rectangle that will hold dirt. You can fret over getting the measurements down to the centimeter but all of the sun, moisture, and temperature changes are going to make your efforts ridiculous. This is rough carpentry and I promise that you can do it. Just take a bit of time to learn the new skill. There are plenty of videos online on how to do this.
If you want to make some of this easier go ahead and order corner brackets that allow you to slip the wood in and out. These will make nice clean corners, you can easily replace the rotting boards, and the setup will be easier. Just search online.
I have always used regular untreated/unpainted/uncoated pine boards to hold my dirt. This seems like the safest option by far; rotting wood in the soil is not going to hurt me. I have seen many photos of people using cinder blocks (I don’t know what’s in them and if it's safe); rubber tires (I know there are heavy metals in there that I don’t like); pressure treated wood (I know folks claim the chemicals only leak out a “small distance” but that’s too close for me); railroad ties (which contain dangerous chemicals); plywood (chemicals in it to make the boards stick together); and galvanized steel (never sure about the coating and what it leeches). So I highly recommend that you just buy regular wood.
Don’t paint it (even the outside) or stain it or try to put “natural” water repellent on it. So just use the wood and realize that you are going to have to replace the boards eventually. But that feels much better than worrying whether the water repellent is leaching into my carrots.
What about cedar or redwood? They are great options as they are more resistant to rot. But if you are just starting off, I suggest you stick with pine/douglas fir. It’s much much much less expensive and will give you half a decade of life before you have to make repairs. If after five years you’re loving gardening, then you can consider replacing the pine with cedar and redwood. I’ve replaced many boards and even rebuilt entire beds and it’s not too hard. But I have yet to use anything other than pine/douglas fir.