A most important part of greenhouse construction. Poor putty, if the glass is lapped and poorly laid, is a source of constant annoyance, waste of coal and injury to the plants. When the glass is butted, unless the house is well and truly built, it will be a botch and failure and will bring censure on this excellent method, which under most circumstances is the way to glaze a commercial house. Some critics may say if good for the commercial man why not or all glass structures? The lapped method is more expensive, but if well and properly laid is undoubtedly a good job, but the butted plan is quicker to lay, easier to repair, much less expensive, and if you ever want to altar or move your houses or wish to remove the glass you can do so with perfect ease. As to tightness for making a warm house both methods when thoroughly done will do that, with a preference toward the butted system.