Yes, it can be that easy. Just get an aged straw bale (say 4 – 6 months old), then using a knife cut a rectangular cavity into the centre of it, say a good handful deep into the bale, pulling out the tuffs of straw as you go. Give it a good watering – cavity and the rest of the bale. Fil the cavity with good quality planting mix, add seedlings, water in and mulch around it. For the mulch you can use the tuffs you took out of the centre of the bale. As you pull the tuffs out, put them in a barrow with water and liquid fertiliser and leave for as long as possible, maybe a day, (before the smell gets to you), then put it back around the plants in the bale, as mulch – delicious!
Done! Now just treat it as a normal raised bed.
In this manner you can use the straw bale as a growing medium for the plants, as well as a conditioner for soil that is too sandy of clayey, as overtime the bale will break down and slowly release its organic matter into the soil, which is great for its health and structure.
Over the seasons as the bale breaks down, you can start to spread it around the garden bed and place a new bale on top. Do this over a few seasons and turn a dead bed into an activated one. It's not instant, but what in good gardening is?
So, if you have places in the garden where the soil is dead, and you want to put life back into it, get an aged straw bale and go to work.
Enjoy!
Peter