[BOB3554]

Hello everyone,a quick mathematics question. I am slowly getting organised to start veggies for the first time in the spring.Will be making some raised beds but have no idea of quantities required to fill them. Beds will be as follows,

   3 beds, each one,    96 inches x 27 inches x  12 inches    
 What will total be if I increase depth to 18 inches, they will sit on heavy clay. What is the opinion out there on stuff to put in, all soil, soil/compost mix or all compost. Hope somebody out there can help, my thanks in advance,
Bob Stephens.

[gregmcalister]

Hi there
Doing a quick calculation I worked out that you'll need roughly 500 litres for every bed i.e. 1500 litres pr 1.5m3 in total.  If you fill this with soil you'll be looking at between 3.75 and 4.05 tonnes of soil for the three beds although compost will be lighter.

If you increase the depth to 18 inches you'll need 729 litres/bed or 2187 litres/~2.2m3 for all three beds giving a weight of soil of between 5.5 and 6 tonnes.

These figures for weight required are just based on assumed values for soil density (2.5-2.7 g/cm3).  The volume will be the same no matter what you choose to fill the beds with though.

Hope this helps
Greg

[penance]

Firstly I would recomend rowlawn topsoil. It is expensive but very nice soil. When I built my raised beds I used Rowlawn for half and onlineturf for the rest. Rowlan stuff has been good, the other was very silty and introduced clubroot.

Both companies have a quantity calculator, stick in your total length, width and hieght and it calculates the volume in M2.
Dont do as I did and go for the calculated amount, I did and it filled all beds with no room for compost/muck. Get the quoted M2 and halve it. Then it would be cheaper and better.

I have 6 8' x 3' beds giving 15m square they are 8" heigh, it was 3 cube meters to fill all the beds.

[Kate and her Ducks]

When I made my raised beds I got some compost at the time and added some soil from digging a pond, they were still only half full but worked fine and would have cost me a fortune to fill up immediately. HAve been gradually filling them up each year with spent growbags and compost from the bins so not costing me anything. Lots of stables also offer muck for free so you can bung a load of that in without breaking the bank!