6 to 8 weeks, when the foliage turns yellow cut it down to about 3 inches. Realize that I am no expert seeing as last year was the first bulbs I had grown, they bloomed in January, then I let them grow in a sunny window until September, I then withheld water, takes a long time for those leaves to yellow, then I was told you should remove them from the pots which I did, cleaned the bulbs up and put them in a cool dark cupboard for about 8 weeks, great success as one is blooming, the other I took out later has a nice scape with a large bud. Anyway that is my experience, good luck with yours..
