Flaking rust

I was rumaging around a reclaimation yard this morning looking for old garden tools as I've finally got my allotment. Of course I couldn't resist taking a photo of the rusty, flaky old metal staircase which I found propped up in the corner.

I'm sure you'll be seeing plenty of my allotment in future - fortunately half of it is given over to soft fruit and there are raised beds.... however, there are plenty of weeds which I must tackle. Any tips on how to get rid of the weeds are much appreciated!