Posted: Today at 15:01
Cheap way of creating raised beds is with scaffold planks. Any reasonable builders merchant can supply them. Two planks tall 2m x1m. Topsoil by the ton is relatively cheap, but It will take 6+ tons to fill the beds. Pure topsoil in a raised bed I wouldn't advise as you need some grit/small stone in it to allow air in the soil.
You'll need 18 inch wooden stakes and nails or screws to construct the beds. I prefer exterior screws myself. One in each corner, maybe one each side about halfway is often the case.
As for planting, well what do you want to grow, veg/flowers or shrubs or a mixture of all three.
If your'e planning to involve young people, then a mixture of annuals and easy growing veg would be best, they produce quick results, and can look very impressive.
Get seed from Wilko, it's cheap and reliable. It doesn't matter what you pick, but it's good to involve any youngsters in the choosing of the seed. They then can see whats going to come up.
Keep a length of scaffold board just over a metre long to lay across the beds. The whole idea behind raised beds is not compact the soil by walking on it.
Seed sowing outside starts in March and can go on till September.
Stagger sowings of quick growing veg for a continuous supply. Late sowings of flower seeds gives you a longer season of colour. Take care to feed the soil with a general purpose fertilizer, you won't know the fertility of the topsoil you'll be getting. Growmore is fine.