You will get the most answers here.

Knowing where you are and how large of a raised garden it will be will help.

tj

Douglas Fir appears to last longest in raised beds and liners do little to slow the wee critters that munch on the wood. How thick the boards should be depends on how high the beds will be. One garden around here has 1 x 6 boards, one high, and is more to define the bed than to raise if. Another garden, 10 blocks away, used 2 x 8 boards with 6 x 6's upright for the corners. Those beds are about 4 feet tall to accommodate seniors.

Soil is composed of the mineral (the sand, silt, and clay), organic matter, air, and water. A good all around soil for a garden is loam, a mix of about 45 percent sand, 25 percent silt, 25 percent clay and 5 percent organic matter. Perhaps this link will be of some help. https://hort.purdue.edu/ext/loam.html Some may suggest buying something called "topsoil". "topsoil" is just the soil on top and it might be something worthwhile (see the loam) or something disastrous and not worth the cost. Perhaps this link will be of some help. http://msue.anr.msu.edu/news/the_shocking_truth_about_topsoil

If the soil put into the raised bed is close to that outlined above drainage will not be a problem, unless the beds are built on top of non draining soil.

Perhaps this link may be of some help. http://www.popularmechanics.com/home/lawn-garden/how-to/g92/build-raised-garden-beds/

kimmq is kimmsr

It is not "wee critters that munch on the wood" that causes the problem - it is how well the wood will hold up to soil moisture. Wood exposed to water rots, some woods faster than others. Douglas fir is not all that long lived when in contact with moisture....only 3-6 years. Pine ditto. But cedars (western red cedar, Alaska cedar, incense cedar and eastern red cedar) are very rot resistant, as is redwood, black walnut, white oak and eucalyptus - anywhere from 10-25 years. Treated doug fir is also good (up to 30 years) but untreated, not at all. And a liner can extend the life of raised bed wood just by virtue of keeping wet soil from direct contact.

As to soil appropriate to a raised bed, garden soil enriched with some compost works perfectly fine - you don't need to get overly creative in the mix. A raised bed is just an elevated garden bed, nothing more. If you do not have sufficient soil available to fill your beds, bagged garden soil or bulk 'garden mix' will work perfectly well although I'd want to add some OM if none included in the mix.

Raised beds sometimes have solid bottoms and are sometimes located on solid surfaces like driveways or patios but open to the ground on the bottom is most desirable, especially for good drainage. So no rock or stone base. This also allows deeper rooted plants to penetrate down into the indigenous soil as well. Decent drainage is usually a given, just based on the bed's elevation.

The "standard" configuration for a raised bed is one that is 8' long by 4' wide. This allows the gardener to access all the plants easily by reach alone without actually entering the bed itself. Height is your choice - if you are growing deeper rooting plants, you might want a deeper bed - but anywhere from 8-16" is about ideal. Obviously the deep the bed, the more soil required.

Watering can be done with a soaker hose, drip, by hand or with a sprinkler - it really doesn't matter as long as the plants receive adequate moisture as needed.

this is a disease and bug forum ... and as you can see.. we still like to help .. but i suggest you google your title ... to find a plethora of ideas ...

all those questions ... and the facts i miss.. that i think are very relevant.. is how high will the structure be ... ergo ... how deep will the soil be ... and why you are doing this ... e.g. wheelchair access .. etc ... also .. what is the native soil ... the number one issue.. in any pot... is drainage ... and we need to know.. if your native soil will allow such from the structure ...

you said: you should have 3 different types of soil in a raised garden bed

==>> to me.. that sounds like you are mixing potting media theory.. with soil issues ... if you plan on filling some large structure with potting media ... it is going to be VERY expensive ... and for the most part.. i dont know why you would go to that expense ... [by the time you buy lots of wood.. and potting media... you might have a couple hundred dollars wrapped up in this.. and if e.g. you were growing veg... it might take you 200 years.. to pay off the investment]

please clearly define the GOAL ... why are you doing this ... we need to start at the beginning of the process.. not at the beginning of the build ..

ken

What I mean by soil I am talking Organic, Manure and soil of some type.

Why a raised bed because we live in a Senior Living, and we can have a garden but it has to be a raised bed.

great answer on where you live ... next ... height.. width and length ...

ken

That is a very good question: I was thinking of 3 to 4 foot wide and 8 foot long not sure how high to make it, I was thinking 16 inches high just what would be the ideal height to make it?

height would depend on how you want to work in it ...

i already mentioned wheelchair.. as an example ... but do you want to be on your knees.. sitting on a bucket ... etc .. or sit on the edge ...

3 foot wide.. is going to make it hard to work .. past 2 feet in ... as i dont recommend walking in such ... unless you can get behind it.. to work the back of it ...

what is the soil below???

when i moved here.. there were some old RR ties ... i used those ... ??? .. i could sit on the edge .. whole the kids played in the sand box ...

not even sure those are sold.. or are safe ... just throwing out ideas ..

does anyone else in the community have such ... if so .. snap some pix.. and we can analyze such for you ..

in the alternative.. talk with them.. and ask them the up and down sides of what they built ...local info is much better than random strangers on the WWW

there is no better info.. than talking to someone who failed.. lol ...

a little math.. with your dimensions.. will tell you how many truckloads of soil you might need ...big is great.. until you start having to hauling soil around.. lol ...

ken

you might want to go small ... maybe half you space .... you can always add more later ... but i would hate to seed you overwhelmed ... and lose faith ...

ken