I used 1.2 kilos of rhubarb because that's what I had. I layered it with the same weight of sugar in a bowl and squeezed the juice of 2 lemons over the lot. I left it for 24 hours.
I smashed a piece of ginger root (about an inch) with my meat tenderiser (mmm you don't really need to know that bit ::)) put it in a muslin bag then put it and all the rhubarb stuff in my jelly pan. Boiled it for 15 mins then removed the ginger. Chopped up about 100gm of crystallised ginger and added it to the pan. I use a cooking thermometer so I just kept going until it reached the temperature for jam setting (about 5-10 minutes). Let it stand for 20 mins than poured into warmed and sterilised jam jars.