| 摘要 |
PROBLEM TO BE SOLVED: To provide an apparatus for growing sweet potato seedlings, which can grow the seedlings of uniform and high quality, good in workability, capable of using late-night power to standardize power consumption and reduce cost, and allowing implementation of planned business for growing sweet potato seedlings. SOLUTION: This apparatus for growing sweet potato seedlings includes earth 4 for growing sweet potato seedlings 6, an insulating electric heater 7 embedded in the earth 4, power supply means 9 for supplying power to the heater 7, and a time switch 8 as a power controlling means which automatically switches on or off the power supply means 9. It keeps the time switch on for a certain period during the night and continuously supplies power to the heater 7 during this period, to maintain temperature of the earth 4 around the roots 6a of the seedlings 6 in an optimum range by heating the earth 4 while it is cooled otherwise, and thereby to grow the seedlings 6.
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