This section is from the book "The Gardener's Monthly And Horticulturist V18", by Thomas Meehan. See also: Four-Season Harvest: Organic Vegetables from Your Home Garden All Year Long.
Get some stout brown paper and cut it into squares of a suitable size, and then roll them up into funnels similar in form to the pointed bags in which grocers put moist sugar. They should be from six to nine inches long, and as soon as rolled into shape pasted up the edge to keep them firm; if for plants in pots, the base of the funnel should be large enough to go over the bulb and a portion of the soil; if for glasses, it should fit the outside of the upper rim of the glass. The pointed end should be cut off, so that when placed over the plants, the light will come in at the top only; the flower-stem will rise up rapidly to reach it, and as soon as it is as long as you desire, take off the funnel and allow it to bloom. After a little practice with this method, you will be able to grow them all of a height, which very much enhances their beauty where a number of them are arranged in a window.- Gardener's Magazine.