Questions about building and gardening in raised beds

[ddiogyn]

I'm thinking about putting up raised beds in my weed garden (that is, part of the garden currently neglected and overrun with weeds!).

I would like to build 6 beds, each 3 x 6 ft and 1.5 ft deep (or maybe 3 long beds, 3 x 16 ft, what do you think?). Are there any great advantages to digging the area on which the beds will be sitting, versus laying the area with newspaper/cardboard/weedblocking membrane? The ground itself both clay-y and chalky, with lots of small rocks/pebbles, and is very compacted.

What should the beds be filled with? Could i reuse my compost (B&Q multipurpose and Homebase Enriched) from this year's container garden (mixing it in with new stuff to make up the difference)? How often do raised beds require watering (a large birch overhangs much of the area, blocking both rain and sun)?

I know it generally isn't recommended to reuse spent compost from container gardening - what about compost from raised beds, does it have to be replaced with each season?

Thanks!

[taff]

usually you'd use a mixture of soil and compost for raised beds, and either fill them all at once [expensive] or fill them from year to year with either your own compost/extra soil/manure etc, so you build a level gradually.
If you do it the second way, you'll probably have to dig the soil underneath, so you have at least something to grow in while you wait to fill the bed.
watering - the first way, not as much as the second way, as tree roots will suck all the moisture out of the soil underneath.
you can re-use your compost, but dont use straight sompost to fill a raised bed as it'll dry out quicker than a mix of soil and compost.
make shorter rather than longer beds as you might get sick of walking all the way round a long one.
if the tree blocks the sun, you'll have to think about what veg isn't particularly fond of the sun, or cut some branches off to let some light through.
it all depends how much work you want to do really.
there's more, and someone will be along shortly.

[digthatchick]

I have been growing in raised beds for about five years now. I have five, mine are 13' x 4' x 8" deep and are placed over a reasonable loam soil.

They are filled with soil and two year old compost (I keep a dozen hens so compost is very rich and easy to achieve) Personally I would break up the underlying soil, whether clay or not, to help introduce worms etc.

Advantages - easier to keep weeded, better control of ph per bed, easier crop rotation and no you don't change compost every year, you just add fresh compost on top! Much tidier if in your own garden (as mine are)

Disadvantages - will dry out much quicker than a conventional veg patch, so plenty of watering ( I have an irrigation system in mine as I got fed up with two hours watering every day) Much more costly if you are on a tight budget, and as a fellow grower said to me the other day .. "much more of a faff then real gardening"! ?

Personally ... I love 'em

[oldie]

I have gone down the raised (and edged) beds and no-dig as rheumatoid arthritis makes digging difficult. I used cardboard/newspaper in the bottom and added soil, compost and manure as available. Once the tomatoes have finished the grow bags or buckets of used compost are mixed into the beds or the compost box. I use straw as a mulch on the beds and paths. Do you have a reason for 1.5ft deep beds? That will take a lot of filling, mine are 9" on top of clay which was forked over first.

[ddiogyn]

@Taff
Yes, i'm not sure how well things will grow under the shade. The area gets about 3 hours direct morning sun and 2 hours direct sun in the late afternoon. The entire midday and early noon sun is blocked by the tree, however. The area is currently covered with weed barrier and used for my courgette vines to sprawl on, they don't seem to be suffering too much (but then again i moved them there when the vines were already very big).

@Digchick
Part of the reason i'm wanting raised beds is the time-consuming watering regime that gardening in containers imposes - it takes me about an hour or so for each watering, up to three times a day if it's hot! How frequently would raised beds need to be watered on a warm day?

@Oldie
1.5ft because i didn't want to dig the underlying soil, but rather treat the raised bed as a giant container. With a lower bed i would imagine the underlying soil would need digging to allow enough room for root growth?

[kingkano]

I built my raised beds this year from Linkaboard, about 16" high. I bought in a load of 'fruit and veg' topsoil to fill them, and added alot of bought compost/homemade compost to top them off. Only things I didnt dare grow is parsnips. I have sweetcorn, tomatoes, everything else growing in there great.

They will need more watering than open ground but less than containers (bigger volume holds water better). This is all variable on how dense you plant (you can push this alot in raised beds I think) and if you mulch etc.

I put down weed membrane as I decided 16" is enough depth and I had very bad perennial weeds in clay underneath. I am going to make some more raised sections to grow parsnips now too

Oh as for sun, you'll have to be willing to gamble. My area is bordered by trees on one side so gets sun from 12 till about 5ish. This has been enough to grow everything surprisingly. My sweetcorn is almost ready to harvest for example. So you might be surprised too.

[Jimmy]

I did a web page that may be of use.

Introduction

The wood fences used don't last as long as pressure treated timber.
But they are free and you can easily replace them when they fail.

Jimmy