set the height of freetextbox

How should I go about setting the height of freetextbox? I want to size the textbox reasonably based on the lenght of the text in the textbox.

From stackoverflow

• simply set the height property of textbox as much you want... like..

  <FTB:FreeTextBox ID="txtDesc" runat="server" Width="590px" Height="300px" ></FTB:FreeTextBox>