JIFFY POT, SINGLE SQUARE, 3.5" X 4.0", 20 PACK, POTS, 20 CELLS, BIODEGRADABLE The Inexpensive, Reliable Way to Start from Seed. Jiffy Pots revolutionized gardening and continue to be one of the most popular ways of growing from seed for transplant into the garden Jiffy Pots are constructed of lightweight, sturdy Canadian sphagnum moss Jiffy Pots are great for annuals, perennials, and vegetables, and are especially effective for hard-to-transplant species Molded into strips for easy handling and inserting into trays.