Raised Bed : Filling and Growing
First time poster, so hi, wave, etc. I've just finished building a raised bed for my lovely wife. I'm more a woodworker than a gardener so my idea of a raised bed is from my mind's eye, not from experience, and having built it I then realised I need to fill it. As it turns out it's quite large, 2.4mx1.2mx0.5m, c. 1m³ internal volume.
I'm not one to ask without doing some research, so I've pulled together my thoughts and am looking for some advice.
The raised bed is built on an area that has been disused for sometime, it's sited next to a holly tree (in the background) and next to where a Eucalyptus tree was (chopped down as was getting very tall and is too close to house). I dug the ground over, down to about 10cm and sieved out all the roots, then levelled and tamped down. The area has been covered in weed control fabric as I'm going to put large pebbles around the bed, and I've lined the bed in the same fabric to stop any soil getting between the sleepers (new untreated oak, so not worried about contamination of the soil).
Question 1: Should I cut out the weed control fabric in the base of the bed? The benefit of the fabric is that it may help prevent the tree roots growing up into the bed, the downside seems to be that it may prevent crops grow deeper than the bed depth (50cm) and also prevent worms getting into the bed.
2. Filling it:
Initially I was going to just buy a bulk bag of topsoil, until I found out that i'll need potentially a couple of bulk bags which could set me back over £100 and that topsoil on it's own is not great for growing veggies in. I understand that I need a mix of soil and compost with some other bits added, ie fertiliser etc. I have also read about the lasagna method, ie throwing a load of stuff in the bottom to rot and putting a layer of soil/MPC on top. Through all my ongoing projects I have lying around:
- a huge bag of larch wood shavings (all untreated wood)
- lots of rubble sacks full of tree roots, leaves, top scrapings. From building a shed foundation where i had to dig the area over and sieve out all the dross.
Question 2: I was planning on throwing the shavings in the bottom, then the old roots/leaves/scrapings on top of them, then filling the remainder (at least the top half) with soil/MPC mix. Does this sound sensible?
3. Growing stuff:
Question 3: With a bed of these dimensions what/how much should I (well the wife and kids; I do woodwork) be able to grow. Could we realistically grow a significant amount of veggies, or should we understand that this is just playing at the edges.
Many thanks in advance for any advice.
PS: Apologies for the essay!