Questions on raised beds

[Ballydoolagh]

Not sure if this is in the right section or not but I have a couple of questions on raised beds.
I wanted to make beds to better divide a field I have. The beds are more to show the boundaries of where I am planting rather than to raise the soil.
I had thought of using something like 6x2 pressure treated timber, having them 1 board high and putting them into the ground about an inch. Then I was going to get polythene and staple it to the inside.
My field is on a slope (gentle but sloped non the less). I was going to have the beds sloped rather than level them up.
Can anyone advise if I am on the correct lines? I'm looking to make about 10 at 4x10 foot sizes so don't want to start off wrong.
Thanks

[MikA]

Don't know much about raised beds in large plots but I would be a bit worried by the thought of the polythene liner. If you had a really heavy spell of rain you may end up with muddy ponds instead of good soil.
If you want to prevent weeds coming through use a weed suppressant membrane instead.

MikA

[Johnboy]

Hi Ballydoolagh,
My beds are what are termed as 'designated beds' that are simply beds with the edges defined with 4 x 1 inch treated timber. My beds vary in width some 4ft some 6ft but all are 33ft long. My Paths are all 30 inches wide. I do not quite understand the polythene bit. Perhaps if you could explain that a little I might understand.
JB.

[Ballydoolagh]

The polythene was to staple to the wood to help prevent it from rotting quicker. It would only be around the perimiter and not on the bottom of the bed. Is this much benefit or will the wood last just as long without? How often do you have to replace yours?
If I was able to make them and add fresh(ish) manure, would it be ok to plant in the spring. Lots of farmers around me but no well rotted stuff.

[FelixLeiter]

Since you're using pressure-treated timber, you don't need to give it any protection. If anything, the polythene could only serve to retain moisture around the wood, which isn't really what you want.
If the only manure you can get is long, dig it in now and it should be about right by the time spring comes.

[glallotments]

The polythene was to staple to the wood to help prevent it from rotting quicker. It would only be around the perimiter and not on the bottom of the bed. Is this much benefit or will the wood last just as long without? How often do you have to replace yours?
If I was able to make them and add fresh(ish) manure, would it be ok to plant in the spring. Lots of farmers around me but no well rotted stuff.

Make sure you check your manure source carefully http://www.kitchengarden.co.uk/forum/viewtopic.php?f=9&t=7863