Potatoes (Solanum tuberosum, in the nightshade family) and sweet potatoes (Ipomoea batatas, in the morning glory family) are unrelated plants, despite the similar names and both producing edible underground storage organs. This leads to major differences in how they germinate (or sprout), start growing, and are cultivated.
Potatoes (regular/Irish potatoes):
They sprout directly from "eyes" on the tuber itself. Gardeners often pre-sprout them through a process called chitting — place seed potatoes in a cool (around 50-60°F/10-15°C), bright, frost-free spot for a few weeks to develop short, sturdy sprouts before planting. This gives them a head start and can increase yields.
You plant the whole tuber (or pieces with eyes) directly into the soil once sprouted and soil is workable.
Sweet potatoes:
They do not sprout the same way. The edible part is a true root, and you don't plant the whole root directly in cold conditions (it often rots). Instead, you produce slips (rooted vine cuttings/sprouts).
To get slips: Suspend a mature sweet potato in water (toothpick method) or partially bury it in moist soil/sand in warm conditions (ideally 75-85°F/24-29°C with high humidity). In 3-8 weeks, shoots (slips) grow from the tuber. Break or twist them off (they root easily), and sometimes root them further in water before transplanting.
This is a separate propagation step — slips are essentially baby plants, not just sprouts on the tuber.
Potatoes: Planted as tubers (or cut pieces) in cooler spring soil (as soon as soil can be worked, often 40-50°F/4-10°C soil temp). They grow into bushy plants and form new tubers underground from stems (stolons).
Planting depth: 3-4 inches, often hilled up as they grow to encourage more tubers.
Sweet potatoes: Planted as slips after the last frost when soil is warm (at least 65°F/18°C, ideally 75°F+/24°C+). They are heat-loving and won't tolerate cold.
Planting: Bury slips so leaves are above ground and roots/lower stem in soil (often horizontally or at an angle). They quickly vine out and spread.
In summary:
| Aspect | Potatoes (regular) | Sweet Potatoes |
|---|---|---|
| Botanical family | Nightshade (Solanaceae) | Morning glory (Convolvulaceae) |
| Starting material | Whole/cut tubers with eyes | Slips (rooted vine sprouts) |
| Pre-planting process | Chitting (cool, light) | Producing slips (warm, often in water/soil) |
| Temperature preference | Cool to moderate | Very warm/hot |
| Planting time | Early spring (cool soil) | After last frost (warm soil) |
| Growth habit | Bushy plants, underground stolons | Long vining plants |
| Time to produce slips/sprouts | Days to weeks (chitting) | 3-8+ weeks for slips |
These differences mean you can't grow them the exact same way — sweet potatoes require more warmth and an extra propagation step, while potatoes are more straightforward from sprouted tubers.