I've never grown a vegetable before, the closest I've got was sprouting a bean on kitchen towel at primary school. Since then I have had an amazing knack of killing every plant I've owned since and it has been joked that I shouldn't even be allowed to look at them.
This year though, my luck seems to be changing. My sugarsnap peas are blooming now and the tuber potatoes I planted about a month ago are needing more soil!
I chose to put 5 tubers in a sack 1/3 full of compost rather than straight in the ground to maximise my crop. I had "chitted" these for a few weeks in a dark cool place a couple of weeks before, but it is not an essential step.
After lots of water, and a bit of waiting, this weekend I added more soil. The stems had reached 15cm so covered 2/3rds of the plants with more compost. By the next time they reach 15cm I will be able to fill the bag completely. Adding soil encourages the plant to keep growing, and your roots will be much longer underground than if the bag was filled completely straight away. Longer roots means more potatoes, so I am looking forward to a bumper crop come harvest time!