Planting seed potatoes correctly means burying certified disease-free tubers 4–6 inches deep in loose, slightly acidic soil after frost risk passes, then hilling soil around the stems as they grow.
The difference between a basket of potatoes and a handful of rotting ones starts with what goes into the ground. Certified disease-free seed tubers avoid the growth inhibitors and soil-borne diseases that ruin grocery-store potatoes. Getting the depth, spacing, and hilling rhythm right converts a simple planting into a reliable crop. Here is the exact sequence from soil prep to final harvest.
Choosing and Preparing Seed Potatoes
Certified seed potatoes are tested for diseases that persist in soil and rot tubers. Grocery potatoes may carry blight or be treated with sprout inhibitors, so seed stock is the only safe start. If a seed potato is larger than a chicken egg, cut it into pieces roughly 1.5–2 ounces each — about the size of a golf ball — with at least one to three eyes per piece. Let cut surfaces dry for two to three days before planting; the callused skin reduces rot in cool, damp soil.
Optional but beneficial: pre-sprout (chit) seed potatoes by placing them in a cool, bright spot — not direct sun — for one to two weeks before planting. Short, sturdy sprouts emerge faster in cold soil than unsprouted tubers. Discard any piece that feels soft or smells musty.
Soil, Timing, and Planting Depth
Potatoes demand loose, well-drained soil rich in organic matter with a pH between 5.5 and 6.5 — slightly acidic conditions that discourage scab. Full sun (six to eight hours daily) is necessary for good yields. Plant when soil temperature reaches at least 45–50°F and all frost risk has passed; cold, wet soil rots seed pieces before they sprout.
Dig a trench or individual holes 4–6 inches deep. Place each seed piece with the sprouts or eyes facing upward, spaced 10–12 inches apart. Rows should run 30–36 inches apart so there is room to hill soil later. Cover the seed pieces with 2–4 inches of soil — not the full depth — so the soil warms around the sprouting tuber.
Hilling: The Critical Repeat Step
When the shoots reach 6–8 inches tall, pull soil from between the rows up around the stems, burying the lower half of each plant. Repeat this hilling every 10–14 days until the plants flower, adding a few inches each time. Hilling prevents light from reaching developing tubers — sunlight turns them green and toxic — and keeps the soil loose for swelling potatoes. Stop hilling when the rows are fully mounded and the plants are blooming.
For container planting, the same hilling logic applies: start with 4–6 inches of potting soil in a container with drainage holes, add the seed potatoes, and cover with 2–4 inches. As plants grow, add more soil up to the rim, always leaving the top leaves exposed.
Common Mistakes That Reduce Yields
Four errors cause most home-garden disappointments. Planting decayed or moldy seed pieces guarantees gaps. Planting too early in soil below 45°F invites rot before sprouting. Crowding (spacing closer than 10 inches) produces small, stunted tubers. Poor drainage or overwatering suffocates roots and softens potatoes. Damaging sprouts when covering also sets growth back a week or more, so handle seed pieces gently.
If you are looking for the best varieties to start with — tested for disease resistance, yield, and flavor in home gardens — our recommended seed potatoes for planting rounds up the top performers by season and use.
FAQs
Can you plant potatoes straight from the grocery store?
It is risky. Most grocery potatoes are treated with sprout inhibitors to extend shelf life, and they can carry blight or other soil diseases that persist in garden beds for years. Certified seed potatoes are the only reliable choice.
How deep should you bury seed potatoes?
Place them 4–6 inches deep, but only cover with 2–4 inches of soil at planting. The rest of the depth comes from hilling soil around the stems later. This keeps soil temperature warm enough for sprouting while protecting the early growth.
What happens if you do not hill potato plants?
Developing tubers push upward and can break through the soil surface. Sunlight turns exposed potatoes green and produces solanine, a toxic compound. Hilling prevents greening, keeps tubers cool, and loosens the soil for larger yields.
References & Sources
- University of Maryland Extension. “Growing Potatoes in a Home Garden.” Covers seed potato selection, cutting, planting depth, and hilling procedure.
- University of Minnesota Extension. “Growing Potatoes in Home Gardens.” Details soil pH requirements, spacing, and common planting mistakes.
- Royal Horticultural Society. “How to Grow Potatoes.” Explains chitting, hilling timing, and container growing methods.