Water-filled containers painted flat black absorb solar warmth during the day and release it at night, so they are worthwhile additions to your season-stretching toolbox.
Straw or hay bales can easily be combined with an old window to make a nifty cold frame.
Plastic-covered tunnels make perfect mini-greenhouses for early spring planting.
Wall O’ Waters are circular cloches, 18 inches tall and 18 inches wide, made of connected, translucent plastic tubes that you fill with water. They absorb and store daytime warmth and moderate cold while providing dependable wind protection.