The practice of warming the rooting medium from below using electric propagation mats, hot water pipes, or decomposing organic matter. This localized warmth stimulates rapid seed germination and fast root development in cuttings while allowing the ambient air in the greenhouse to remain cooler. Propagators rely on it to establish strong root systems before the top foliage grows too large.
Make sure the propagation mats are set to 21 degrees so those pepper seeds get enough bottom heat to pop this week.
Too much bottom heat will dry out the compost rapidly, requiring closer attention to watering schedules.
Related terms
Hot bed
A glass-covered garden frame heated from below by decomposing organic matter.
Nursery
A dedicated facility or area where young plants or animals are propagated and raised.
Forcing
The horticultural practice of artificially manipulating a plant's environment to induce out-of-season blooming or fruiting.
Under glass
Plants grown in a controlled, enclosed environment like a greenhouse.