Calculation of soil and compost

Consider which size planters you need, where to put it and how to fill it.

Raised planters can be placed directly onto soil, lawn or paving and can be filled directly with topsoil and/or compost.

Calculating the quantity of soil you will require to fill your planter is relatively simple;

  • multiply the length of your bed by the width and the depth in metres, then multiply by 1000 and the figure you arrive at is the amount of compost you’ll need in litres.

example : .8m wide x .8m deep x .76 deep = .8 x .8 x .76 x 1000= 486 litres

Fill your beds with 75% topsoil and use a bulky organic matter – such as farmyard manure or home-made compost – to make up the other 25%.

One of the benefits of a raised bed is the fact you can tailor the growing medium to the plants you are wishing to grow.  For example you can use ericaceous compost for acid loving plants or you may want to grow carrots in sand.

If you want to improve the drainage of your bed you can add a layer of  gravel approximately 5cm / 2” deep at the base, but note that the level of drainage will be dictated mainly by the ground that the bed is sitting on.  If for example the bed is sitting on a free draining sandy soil you may want to lay down a semi-permeable ground sheet beneath the bed to reduce the drainage.

Our specially designed Raised Bed Liners  when positioning your bed on a patio, concrete or other hardstanding area. Not only will these thick, one piece, non-woven polypropylene fabric liners protect the timber frame of the bed even further but they will cut down on the leaching of sand and other fine soil particles – and they make emptying a bed much easier at the end of the season too!

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