Preparing the ground
If your new bed is going on an part of a lawn mark out the area and remove the turf. If you are making sveral beds you can stack the turf grass side down. When it has broken down it makes a good ingredient for potting compost. Unlike the advice in the SqFt book, do not replace the soil with a ‘mix’ – use what is there and improve it if required.
If the ground has been walked on, or is part of a garden that has not been disturbed for many years, it will need to be dug over. This will improve drainage, get some air in and breakdown the soil so that seeds can be planted. The way to do this is to use the standard method common to all gardening – double digging. This does not mean cultivating the area twice! It is hard work but with such a small plot it should be within the capabilities of most gardeners. If you have a health problem consult your doctor before starting or get a friend/neighbour to help.
How to double dig
Digging is best done in the autumn as it gives time for the soil to be broken down by frost. If you dig at other times and your soil is not fine enough for seed sowing you can add a layer of home made compost, or commercial peat free compost, over the surface to make a good seed bed. Heavy rain compacts soil so if you do dig in the autumn cover the bed to keep the rain off.
Pleas note: the following pictures show the double digging technique in a much bigger bed. The same rules apply for a 4ft (1.2m) square bed.
Improving the soil
Add around 30 litres of garden compost when you dig the new bed. If you do not have home made or garden compost then use some bagged soil improver from a garden centre or local DIY store. Fork in the compost/soil improver into the top 4-6 inches (10-15cms), do not bury it.
Edging the bed
When you have finished digging you can edge the bed with timber or other suitable material. Avoid using pressure treated timber as the preservative used may contain chemicals which could leach into the soil. The board should be 4”- 6” deep but you can use a higher surround if required. Some people have used upturned bricks, roofing tiles and concrete blocks. It does not have to be timber!