A multiplication technique by sprout cutting (spc) was developed at La Pocatière from 1988 to 1992. Tubers (t) or mini-tubers (mt) were warmed and, if necessary, treated to break dormancy. After 2 to 4 weeks of presprouting, they were planted 50 to 100 t per flat (28 × 53 cm) half filled with a soil mixture. The t or mt were planted partially in soil, leaving the bud end out. They produced roots in 3 to 8 days under 16 hours of light at 22 to 24C. When 50% of the sprouts have 3 to 4 cm, they were placed in the dark for 3 days and under the initial lighting condition on day 4. The sprouts were cut on day 5. The mother plants were maintained in the same conditions for another 72 hours before repeating the cycle 6 to 10 times (with the same t or mt). The multiplication rate depended on tuber size, storage period, and cultivar. The t (30 mm) and mt (15 mm) of `Novachip' with 14 and 7 months of storage, respectively, produced 55 and 4.3 spc/t or mt in four multiplications over 28 days. The mt (12 mm) of `Tolaas' with 6 months of storage and without breaking dormancy produced 10.3 spc/mt in eight multiplications over 87 days (it took 4 weeks to grow). An equation considering weeks of storage and t size has been developed with six cultivars and four seedlings to calculate the number of plants multiplied in 1 to 7 weeks.