Buy living lettuce. Usually sold as Organically, Hydroponically grown lettuce. Clip off outer leaves and use. Leave the core leaves intact. Place in a glass of filtered water for a few days in a window sill. Trim off less lively leaves. Plant in rich soil up to base of core leaves. Plant should last through many cuttings as long as you cut from the outer leaves and leave a small inner core. Love the sweet tender butter lettuce. The plastic shell makes a good seed starter atrium as shown. Enjoy!