During the winter in Nepals middle mountains, the soil temperature generally remains at 5-10oC above the ambient air temperature. This principle was used to design a simple, inexpensive, and effective nursery technology for raising vegetable and horticulture seedlings in colder regions. The polypit technology allows seedlings to be raised by protecting them from the freezing temperatures that occur mostly at night.
Polypits are about 1m deep pits dug into the ground and covered with semitransparent polythene sheets, preferably UV stabilised and supported on bamboo frames. A 30 cm high mud wall is built across the slope on the upper side of the pit. The polythene sheet is sealed on the upper side of the pit, leaving three sides unsealed but held down with stones that can be lifted to access the pit. The base and sides of the polypit are left as they are with no form of plastering.
WOCAT database reference: QT NEP19
Location: Panchkhal VDC of the Jhikhu Khola watershed, Kabhrepalanchok district, Nepal
Technology area: <1 km2
SWC measure: Structural
Land use: Annual cropping
Climate: Humid subtropical
Related approach: Not described
Compiled by: Madhav Dhakal, ICIMOD
Date: November 2006
light green: districts in 2007