Filling a raised bed

Hi, I built an 8x4 raised bed last weekend and have worked out it will take 700 litres to fill it, and was initially going to buy 1m3 of Rolawn vegetable topsoil, but on second thoughts decided against shelling out £100 on soil. So I'm looking at filling it with bags of compost and topsoil plus anything else I can get my hands on.

So what I'm wondering is, will I be okay to add about 450 litres of multi-purpose compost, 200 or so litres of bagged topsoil, and 50 or so litres of homemade compost?? Plus maybe a few bucketfuls of leaf mould from the woods and maybe some grit or sand. Will this allow me to grow things like onions, carrots, cabbage, beetroot and courgette??

 

A cheaper option than using compost Rod would be to use dark or sedge peat. Mix this with the topsoil and garden compost and you will have a good planting mix. when you have done that you can add leafmould to adjust the acidity.:thumb:

 

Ahhhhh :gnthb: Forgive my ignorance Dai, but can you buy dark or sedge peat in bags at places like B&Q and garden centres?? Is it the same as moss peat?? I'm just starting out at this gardening malarkey. :flag: Would 450 or so litres of peat plus 200 litres of topsoil and 50 or so litres of garden compost give an alright mix? Or would it need more topsoil? Also, what is the ideal pH of the soil?

 

I think any of those combinations would do a better job than my bog-standard clay I have started with :thumb: however I would tend towards more soil - 50% soil at least. But for sure the things will grow in 100% general purpose compost, I just think for future years a higher ratio of soil, initially, is preferable.

 

You should be able to get the peat in any half decent garden centre, using multi purpose compost is just throwing money away. A mix of 50% peat/garden compost and 50% topsoil would be fine. The best soil, nutrient wise, is clay, so don`t just dump it.:thumb:

 

"The best soil, nutrient wise, is clay, so don`t just dump it"

Indeed, sorry didn't mean to imply that I would throw mine away! I'm working to improve it, over time. I was just being jealous of someone starting a vegetable patch by going to their garden centre any buying the ideal mix of soil but in fact ... why not! Its just that my vegetable patch is about an acre, and I don't think my DW would like 1 acre's worth of 75 litres bags of Compost showing up on the credit card bill!

 

Is Irish Moss Peat the same stuff?? :cnfs: The bed has been built on a lawn, which has extreme clay beneath it. Am I right in thinking I should just dig the lawn over and break it up and then fill the bed?? It's 10" deep the bed, so don't want the grass coming up through it.

 

No Rod, moss peat is NOT the same as sedge peat. BUT if you can get that cheaper, then do so, but make sure you rehydrate it before you use it. Yes you should turn over the ground in the base of the bed.:thumb:

 

Whats wrong with using the soil you ar just about to bury under a load of compost?

 

rodofgod76, just how deep is this raised bed you've built ? It seems like a lot of filling ! Cheers...freddy.

 

What about spent mushroom compost mixed with the clay soil?
£100 for soil seems pricey, a definite case of where there`s muck there`s money :wink:

 

Not sure TBH. It's a lawn at present, which was prone to flooding. Made a soakaway there a couple of months ago which seems to have cured the problem. *fingers crossed* Just not sure how I'm meant to fill a raised bed with the soil from beneath it?! :cnfs:

It's 240mm deep freddy.

Where would I lay my hands on that?? From what I've read, the organic matter blended into many vegetable soils sold by companies like Rolawn and Dandy's is in fact spent mushroom compost.

 

Ok rodofgod76. One more question, have you turned over the soil yet ? The reason I ask is because you may well be surprised how much the soil fills the bed once it's tuned. My beds are pretty much the same size and they didn't really take a lot of filling, around 4 or 5 bags of 'stuff'. With mine, I removed the turf then took out a spades depth (putting it to one side) then tuned over the bottom. I then put back the turf (upside down) and then the soil. Like I said, it doesn't really take a lot. Sure, it sinks after a while, but in the meantime you can be adding garden compost to make up the level. Hope this helps. Cheers...freddy.

 

"Just not sure how I'm meant to fill a raised bed with the soil from beneath it?! "

Freddy has answered your question

 

"What about spent mushroom compost mixed with the clay soil?"

Excellent idea! Might be slightly alkaline, but worth doing just-the-once for sure.

"Just not sure how I'm meant to fill a raised bed with the soil from beneath it?!"

Nothing wrong with that at all. If your existing soil is solid concrete or whatever, then obviously it would be a problem. But if you have soil, including "not very good soil", its will be very beneficial.

The approach I am most familiar with, when making raised beds, is:

Dig the soil thoroughly once. Build raised bed on top of it. Never dig the soil EVER again. Usually the initial digging of the bed would double-deep (so two spade depths, but make sure you do NOT mix the soil from top spade's depth with the bottom "sub soil"). Digging will loosen the soil, allowing the plant roots to get down into it easily, and will help with drainage.

"It's 240mm deep"

So that's about a "spit" (depth of a spade) of extra soil

I reckon if you dug the area, then put 120CM of good-stuff on top that would do you, ASSUMING that you will put more good stuff on the beds each year. If you get successful at making your own compost you should not need to buy anything extra, just add your home-made compost on top in the Autumn, particularly if you have access to some fresh manure that you can incorporate into your compost heap (i.e. which will increase the amount of material you have available for your compost heap AND will boost the temperature of the compost heap which will accelerate the composting process)