I find grow-bags a pain to use and the big thick ones take up so much room.  I use cheap builders buckets with holes drilled into the base and fill them with compost.

Most of my growing that is not in raised beds is in buckets and bags. Just thought that I would experiment but maybe not. I have a small (very) greenhouse where I start my seeds off and a grow bag would fit neatly in the bottom. Why do you find them a pain to use?

I've just watched a youtube vid where someone put potatoes on the ground then covered them with grass clippings. Has anyone tried this? Do the grass clippings get too hot/turn into a mat? On the vid the woman only showed her starting the process then harvesting a different crop

I don't see how this would work if they were just under a layer of grass clippings, tbh.

In this video https://www.youtube.com/watch?v=Y5gOrUMEuw8  she says she uses a 6in layer of grass plus 6-8ins of old chicken bedding... and then says she earthed them up( with more clippings/manure I suppose) so that's clearly enough for the potatoes to grow as normal..
It is however, an awful lot of material to collect... great if you do actually have access to large quantities of old chicken bedding and lawn clippings, though 

Grey but only 7 degrees a bit windy too.

The same, with added rain showers.

I find grow-bags a pain to use and the big thick ones take up so much room.  I use cheap builders buckets with holes drilled into the base and fill them with compost.

If you would really rather use a bagged product than a pot of some sort, a small bag of compost sat on its end with some drainage holes poked in the base and slit open at the top, is much easier to keep watered.  If you go as large as a 50L bag you could put 2 plants in, 1 per bag if you go for 20L. 

A cane inside each corner stops it spinning.  Rope and gazebo pegs would do similar but less secure.

If you throw fleece or plastic over it you have a mobile cold frame.
Wrap string around the outside of the canes would enough support for shortish peas.
Netting over it to protect all sorts

Here's what's left of one enjoying a new life holding the coldframe open.