Q: Can I use treated lumber?
A: Yes. They have certain lumbers treated that are not as bad as old "PRESSURE TREATING". Lumber being exposed, only water and chemicals from garden soil will get into it not the opposit.

Q: How high/tall should the beds be?
A: It would depen on the type of native soil and type of vegetable one wants to plant in it. I would say 8" is minimum, to make your efforts worthwhile.
Q: What dirt? Do I have topsoil trucked in, or do I buy bagged dirt at Lowes?

A: Again, it depends. If you have good native soil, you can use that. Otherwise you have to find other source. But buying BAGGED TOP SOIL would be to costly if you want to have a sizable garden.So then buying by cubic yard (not necessarily a truck load) makes sense.

Q: Can I build plant-specific beds, i.e., long, narrow (2 feet wide?) beds for peas and beans and other climbing plants?
A: Making raised bed is COSTLY, in terms dollars and effort spent. You have to maximize your returns.
So, by making it too narrow, you are wasting your resources. By making it perfectly square, you will maximize your returns but it might not be practical.
That is why raised beds are made in rectangular shape.
The length is a matter of choice and the land that is avaialble. BUT width is a matter of human ergonomics. It should be of such a widht that the gardener can reach half way from each side, comfortably.

Q: Can I continue to plant tomatoes in the same bed year after year? I thought I had to rotate tomatoes.
A: Crop rotation is a different concept

1. Can I use treated lumber?

If you read all of the literature about the second generation treated lumber, it doesn't sound that bad. That being said, I would never put treated lumber in close proximity to my edible crops. What's close proximity? Well, some say 12 inches is sufficient while others (me included) think that 10 feet is too close. With the cheap cost of untreated lumber, why take the chance? Besides, you don't actually need to enclose your raised beds. I have over 2500 sqft of raised beds, and none of them are enclosed. If, however, you like the look and tidiness of enclosed beds, go with cedar (will last you probably 7-10 years) or untreated quality pine (will last you probably 3-5 years). YRMV

2. How high/tall should the beds be?

Again, depends on a number of factors. If the beds are not enclosed, then 4-6 inches is more than sufficient. If they are enclosed, then you want to fill the enclosure with soil. Thus, if you use a 2x6, then 5.5" should do it. If you use a 2x8, then 7.5", etc. Which should you use? Well, depends on what kind of soil you have underneath. If you are in a suburban setting, chances are your soil is crap. In that case, you are going to want better soil and more of it on top, probably 6-8 inches. I have heard of some going as high as 10-12 inches, but that's overkill IMHO.

3. What dirt? Do I have topsoil trucked in, or do I buy bagged dirt at Lowes?

First off, it is soil, not dirt. Dirt is for backfilling construction, soil is for growing. To that end, having topsoil trucked in may not help much. Garden topsoil is usually targeted for grass lawns and will contain (usually) soil very deficient in any nutrient content or organic matter. Now, triple-mix is a different story: that is usually composted manure, loam soil and sand. However, not all triple-mix is created equally, and most is highly inadequate for growing vegetables, a high demand crop. If you require numerous cubic yards of soil (1 cubic yard is 27 cubic feet, or a space roughly 9'x6' with a 6" depth) then I would try to find a good local source for triple mix and then supplement with as much good quality compost as you can. Where do you find the compost? Well, that can be tricky. Making your own is always the best, but in a pinch, go grab some bagged compost at your local box store. Try to get a variety of types of compost (i.e. sheep, mushroom, bovine, etc.). You will probably need to fertilize your soil at some point, but that is an entirely different conversation.

4. Can I build plant-specific beds, i.e., long, narrow (2 feet wide?) beds for peas and beans and other climbing plants?

Why not? You are limited only by creativity. My only suggestion is to not build your beds wider than 48". It makes it very difficult to get to the middle.

5. Can I continue to plant tomatoes in the same bed year after year? I thought I had to rotate tomatoes.

And herein lies the problem with permanent vegetable beds. Sooner rather than later you are going to completely drain the life out of the soil unless you are closely nurturing it and replacing lost nutrients and organic matter. This can happen as quickly as three seasons. Further, diseases will catch up to you. You want to rotate your crops, ideally every year, with every third or fourth year planting a green manure or cover crop to allow the soil to recoup. Choose to ignore this kind of advice at your own peril.

Hope all of that helps!

Michael

The title of your question leads me to believe that you have likely read through many of the previous discussions available here on your individual questions. If not be sure to do so for lots more info and opinions. Meanwhile the following is JMO. ;)

1) New lumber? You can but I wouldn't. Many other better options available. Old PT lumber that has been well aged/previously used, all sorts of concrete or stone blocks, no frame at all just trenched edges, Trex, plastics, even old used railroad ties,etc.

2) 8-12"

3) a good quality mix of 1/2 and 1/2 good dirt and compost. Contact local landscapers for bulk pricing.

4) not the usual approach and I think you will regret the lack of gardening flexibility that results but you can if you wish

5) one of the flexibility issues - you don't HAVE to rotate - many can't and don't (I don't) but only IF you keep the beds well refurbished and amended with lots of fresh compost every year. But if you construct the beds normally, they will still need fresh compost every year but then rotation from bed to bed is easy.

Hope this helps.

Dave

PS: you'll find lots of discussions and details on filling the beds over on the Soil & Compost forum too.

Here is a link that might be useful: Raised bed building discussions

If in the fall you sow winter wheat or ryegrass, you will not only have a lot of material for composting in the spring, you will also help replenish the soil, have a nicer looking bed over the winter and can till the roots in in the spring.

Mike

I started my beds by simply placing the boards on top of the existing lawn in long rectangles. I'd got some 2 X 12's salvaged from a roof that had been replaced (my Dad's)and wanted to maximize the garden area with as little waste of wood as possible. So my beds are 4' wide and about 28 feet long. I find the width is ok for stuff like tomatoes, peppers etc but a little wide to easily reach ground in the center.

The area left between the beds was left in lawn grass and just wide enough to run my lawn mower down. That cuts down tracking mud and I don't waste materials mulching.

My beds are not true "raised" beds as I dug down a little to turn the soil and then applied a heavy layer of compost. I add compost as it becomes available from one of my piles. So at times it is raised and others reduces to close to ground level. But the soil inside is soft and easily worked.

Howdy Brother,
You can check out my Raised Beds, this link is for #2 of nine, watch all nine to get the full picture... they are only a minute apiece....

http://www.youtube.com/watch?v=zGqOECST5EA&feature=related

Here is a link that might be useful: Jon's Raised Beds for 2010

There is a raised bed and a framed or walled bed, and then a combination of the two.
So, it is possible to have a raised bed without any frame around it. Also you can frame a bed without raising it.

To me, the pros of raised bed, as far as the actual gardening is concerned, is to provide drainage and prevent run off water from getting into it.
Framing is a design and organizational element.

"First off, it is soil, not dirt. Dirt is for backfilling construction, soil is for growing."

Actually not. It's OK to call garden dirt soil if you must, but the stuff used in construction as an engineering material is referred to in the biz as soil. It may be clay, silt, sand, gravel, crushed stone, cobbles or any mixture of those. It is all soil. To a civil engineer, dirt is the stuff you need to wash off of yourself at the end of the day.

Jim, a plain dirt gardener.

You've gotten some good opinions here already, but I wanted to throw out the idea that you might want to check out the book "All New Square Foot Gardening" by Mel Bartholomew. If you aren't familiar with the SFG technique, see if the book (or the original from about 1981) is available at your library. It gives a wealth of interesting info about raised bed gardening, including useful thoughts about how to size your beds. For instance, if you follow the general principles of SFG (I do about 80% of his recommendations), then you could figure out exactly how to size and site your beds for the purposes of what you want to grow.
He also has a unique perspective on growing medium AKA dirt AKA soil. It can be pricy to start up with his method, because he specifies using a mix of 1/3 mixed compost, 1/3 peat moss and 1/3 vermiculite (a lot of people use perlite instead), but I have never ever seen such luxurious, lovely, perfectly draining soil in my life. The one thing to note is that in Year 1 you may need to amend your soil mix a bit because a lot of people find that it's not quite nutrient-rich enough for some veggies when it's so new.
Hope this helps!
There's also a pretty active SFG forum here on GW, and even if you end up adopting only one idea, it's great reading :)

Some other thoughts than were presented above. It appears that some kind of lumber is the most commonly used way of framing out raised beds. Likely because it's the least expensive (in the short run). But, when you put wood next to moist soil, it's going to rot, and then you have to re-do your beds down the road. I'm not even going near the pressure treated discussion since I don't consider myself well enough informed. I would just point out that there is "lumber" made of recycled plastic. It looks nice and would last indefinitely. There is also brick or stone. I used the decorative concrete blocks that don't require mortar. My beds are on a hillside, so these were easy to use, are basicially low retaining walls, look nice, and are wide enough for me to sit on as I work. It's true they cost more than wood would have. But, I was able to do the construction ALL by myself and I should never have to do it again. Land and money permitting, you can add new beds indefinitely.

This is just my second year with raised beds, but I love them. I have nine beds that are 8 feet by 3.5 feet wide. If I'd had room, I would have built them longer, but not wider. They are just the right width for me to reach into from any side and never step into the soil (dirt) of the bed. Being on a slope, they are about 6 inches high on the slope side and a foot high on the front. When I built them, I dug down a foot into the native soil, loosening it well. Then I filled the framed beds with manure and compost, as well as the dirt I dug out of the paths, levelling them up. Just for your info, I used about 3 large pick up truck loads of manure that I got from a local stable, plus a year's worth of compost from my yard.
I'm guessing it was probably close to a pick up load too. One caution: the manure had alot of sawdust in it from the stalls and I do believe it tied up the nitrogen for the first couple of months. I used fertilizer as a supplement. The situation seemed to right itself by mid summer.

I started out by mixing herbs, flowers and vegetables into my beds. It's such a lovely idea...but it didn't work very well in my long growing season. I have time for two summer crops of vegetables and just as the flowers were hitting their stride, it was time to pull out the old and plant the new. This year, I am going to plant one crop per bed for simplicity's sake.

Rotation: I plan to plant three beds each year with one type of crop: 1. tomatoes, peppers, eggplants (all in the Solanacaea family. 2. squash, cucumbers, melons, and 3. beans, cowpeas and limas. I will rotate each family of plants each year so that no family will be planted in the same ground more often than every three years. My winter garden fills three beds, so I will rotate those crops to a different set of beds each year too. The remaining beds will have green manures planted in them through the winter.

Last year, I used Mel Bartholomew's spacings for most of my crops. For the most part, they worked well. The tomatoes took more space than he called for (I plan to put three plants per bed this year with an edging of marigolds. Tomatoes being a long season crop, you know.)
Like nyc, I recommend his Square Foot Gardening book, especially the first edition. You may not want to use every single idea he gives, but there's an awful lot of great value in it. One note. Definitely make your paths at least 3 feet wide so you can get a wheelbarrow into your beds.

Here's my recipe for success with vegetable gardening:
Read all you can, especially books that are written for your geographical region.
Try stuff.
Expect to succeed: do that again.
Expect to fail: do something different next year.
Tend your soil.
Have fun!

Fabulous post, donnabaskets! I ran out of time earlier and forgot to mention composite lumber in my post, but I actually built my raised beds with it. At my Home Depot in the suburbs of NYC, an 8' length of 7.25"x3/4" costs about $20. To compare that to any of the new lumber they sell in roughly similar sizes, it's more than twice the cost. In our case, we decided we were OK with the higher up front cost though because as donna mentioned, we should never have to replace my beds. This composite lumber is completely non-toxic, therefore food-safe, and it's also a green alternative since it's made from recycled plastics and sawdust.
Height of beds: mine are going to be 14.5" tall, mainly because although Mr. SFG thinks 6" of good soil is enough, I don't fully agree; and secondarily for aesthetics and usefulness (easier to tend taller beds). The third reason is that I want to grow some longer crops (leeks, long carrots, etc.) and rotate them from year to year.
Segue to my thoughts on rotation: in my layout I can't easily rotate my tomatoes because of where my trellising is located, though I can rotate the brassicas and legumes. My strategy for dealing with the tomato beds is simply to enrich the soil heavily with compost during and after the growing season. Here's a great thread specifically about rotation of tomatoes; I found this really useful a couple of years ago--http://forums2.gardenweb.com/forums/load/organic/msg0820593832657.html

And now I'm out of time again!

There is indeed some great info here. I'll just add that I do raise tomatoes in the same bed, and it is not something I would reccomend. I add compost, mulch, worm compost, everything I can get my hands on to try to maximize the health of the soil. But, You Will Have Disease Problems! If I had more room in the sunniest part of my garden I would rotate my tomatoes all the time. That being said, I raise a lot of tomatoes from a few plants, I'm talking buckets full. but as I said, I wouldn't do it this way if I had a choice. The main thing is to have fun while your at it...steve

You've gotten lots of great advice. I just thought I'd chime in on the question about beds designed for specific veggies. I would HIGHLY recommend designing the beds in a modular fashion, as it will give you so much more flexibility. What I mean by this is to use a common denominator for the bed dimensions. For instance, I use 4' lengths. This is convenient for the lengths lumber is sold in, and I can build trellises built in 4' sections and move them to any bed in the garden as needed. Another example of this application is that I am building a chicken tractor this spring, and will design it to fit perfectly on all of my 4' wide beds, so that I can have the chickens debug, weed and fertilize the fallow beds. Also, narrow beds may not work well if you're in an arid area, like I am. I find it difficult to grow anything very well in the 4-6" closest to the side of the raised bed because that area dries out quickly after watering.