mrssue wrote:
Hi, I am fairly new to gardening and wonder if it is ok to use
railway sleepers to construct raised beds - are there any concerns
using these as they have been chemically treated. Any help will be
much appreciated. Also is there an optimum size for the bed?

Often sleepers have been treated with toxic chemicals and so they would not
be suitable for vegetables, find out from the source what they have been
treated with and then research the risks of that treatment. Some are timber
that is durable in contact with the soil without treatment (and may have
never actually been used on a railway) so they would OK.

The bed should be a width that you can readily work from the side without
standing or kneeling on the bed, so it depends on your height and
flexibility. As a guide 3' to 4' (90-120cm) or half that if you can only
access one side. The length is a compromise between reducing land lost to
paths (longer is better) and the convenience getting between paths without
having to jump over (shorter is better). As a guide 8' to 15' (2 -5m) ,
mine are 32' (10m) but I am nimble :-) The size and shape of the area
available is a factor of course. It is good to make the paths wide enough
for a barrow if you can spare the space. Full sun is important for most
vegetables. It is usual to orient the longest side north-south to get even
sunlight on both sides.

David