PROBLEM TO BE SOLVED: To provide preparation methods of mixed planting seedlings by which the runner seedling of Ipomoea batatas becomes easy to insert when preparing mixed planting seedlings.SOLUTION: When preparing mixed planting seedlings consisting of first seedlings raised from seeds seeded in a raising seedling cell 121 of a seedling tray by a sowing machine and second seedlings transplanted in the same raising seedling cell 121 after the first seedlings have been grown up, the sowing machine sows seeds avoiding the center portion of the raising seedling cell 121, the position to transplant the second seedling is secured in the center portion or in the vicinity of the center portion of the raising seedling cell 121, the sowing machine is equipped with a sowing delivery member 69 for sowing the seeds on a ridging S supplied to the raising seedling cell 121. A perforation projection part 69a for forming in the ridging S the sowing hole into which the seeds enter avoiding the center of the raising seedling cell 121 is formed in the sowing delivery member 69, and the first seedling is grown in the position away from the center portion of the raising seedling cell 121 when sown on the planting hole formed by the perforation projection part 69a.SELECTED DRAWING: Figure 9【課題】混植苗を作る際、甘藷の蔓苗を挿し込みやすくする混植苗の作成方法を提供する。【解決手段】苗トレイの育苗セル１２１に播種機で播種した種子から育苗する第１苗と、第１苗を成長させてから同一の育苗セル１２１に第２苗を移植して混植苗を作成する際、播種機は、育苗セル１２１の中心部を避けて種子を播種し、育苗セル１２１の中心部、または中心部の近傍に第２苗の移植位置を確保すると共に、播種機は、育苗セル１２１に投入された培土Ｓに種子を播種する播種繰出部材６９を備え、播種繰出部材６９には育苗セル１２１の中心部を避けて種子が入り込む播種穴を培土Ｓに形成する穴開け突起部６９ａを形成し、穴開け突起部６９ａが形成した播種穴に播種すると、第１苗が育苗セル１２１の中心部から離間する位置で生育される。【選択図】図９
