"SLIPS" AND PLANTING
There are many sweet potato varieties, with big differences between them. It is necessary to find the variety most suitable to the intended growing region, since the variation in varieties behavior under different growing regions can be very big. A certain variety can look nice and have high yields in one region, while in another region, with different growing conditions it may grow very differently and yield poorly. Variety trials are therefore required in order to identify the most suitable variety for the place in question.
The source of the slips (sweet potato propagation sprouts are called Slips) must be free of viruses and diseases. A closed nursery is first established in a 50 mesh net-house, where the seedlings received from a tissue culture nursery are planted. Three to four weeks after planting, propagation may commence in the net-house. This is done by cutting sprouts from the plants and planting them until the net-house is full. The amount of plants in the net-house, which are the source for the slips needed to plant the commercial field, must be calculated so that it supplies the needed amount of those slips. 65,000-75,000 slips are required per hectare of a commercial field.
Slips for the commercial field are prepared by cutting sprouts from the plants in the net-house nursery. The slip should be 15-20 cm long, and should have 3 to 5 eyes. The slips must be kept in well-shaded place with high humidity until planted.
Planting is done on 55-60 cm wide ridges of moist soil. Planting distance along the ridge is 15-20 cm between plants. The slip should be planted so that 2 eyes are covered by soil and the soil around it is tightened well. Since the slips are planted without roots, it is very important to irrigate them as soon as possible after planting and to continue irrigating for several days until good rooting is achieved.