Potatoes grow well in raised beds because the soil warms faster and drains better than ground beds, and you can pile soil higher as the plants grow

Potatoes need loose, well-draining soil and room to expand underground as tubers form. A raised bed gives you both. The key difference from ground planting is that you'll add soil in layers as the potato plants grow taller—a process called hilling—which keeps developing potatoes covered and prevents them from turning green and toxic when exposed to sunlight.

Start with seed potatoes (small whole potatoes or cut pieces with at least two eyes, or buds), not grocery store potatoes, which are often treated to prevent sprouting. Plant them 4 inches deep in spring, about 2 weeks before your last frost date. As the plant grows 6 to 8 inches tall, cover the lower stem with 3 to 4 inches of fresh soil. Repeat this every few weeks until the bed is full or the plant flowers. Harvest 70 to 120 days after planting, depending on the variety.

Key Takeaways

  • Use seed potatoes from a garden center or seed catalog, not potatoes from the grocery store, because store potatoes are treated to prevent sprouting.
  • Plant seed potatoes 4 inches deep in spring, about 2 weeks before your last frost date in your area.
  • Hill the soil—add 3 to 4 inches of fresh soil around the stem—every few weeks as the plant grows, which protects developing potatoes from sunlight and increases yield.
  • Harvest when the plant flowers or dies back, usually 70 to 120 days after planting depending on variety.
  • A raised bed 12 inches deep works for most potato varieties, but 18 inches deep gives more room for larger tubers.

Choosing a raised bed depth and soil mix

Potato beds need to be at least 12 inches deep to give tubers room to expand. If you want larger potatoes or plan to hill aggressively, 18 inches is better. The width and length don't matter as much—a 4-by-8-foot bed is standard and holds about 20 seed potatoes, but you can use any size.

Fill the bed with a mix of topsoil and compost. A 50-50 blend works well. Potatoes prefer slightly acidic soil (pH 6.0 to 6.8) and loose texture, so avoid heavy clay. If your soil is compacted or clay-heavy, add extra compost or aged bark to lighten it. The soil should feel crumbly and hold together when squeezed, then fall apart when you open your hand.

Planting seed potatoes at the right depth and spacing

Buy seed potatoes from a garden center or seed catalog in early spring. They're small potatoes bred to sprout reliably and are disease-free. If a seed potato is larger than a golf ball, cut it into pieces with at least two eyes each. Let cut pieces sit for 1 to 2 days before planting so the cut surface calluses over and resists rot.

Plant seed potatoes 4 inches deep and 12 inches apart in rows, or scatter them across the bed if you prefer. Space rows 18 inches apart. Water the bed after planting so the soil settles around the seed potatoes. The soil should stay moist but not waterlogged for the next 2 to 3 weeks while sprouts emerge.

Hilling: the step that increases your harvest

Hilling is what makes raised beds especially good for potatoes. When the plant is 6 to 8 inches tall, pull loose soil up around the stem, covering the lower half. This buries the stem, which then sprouts roots along its buried length. Those roots grow new potatoes. Repeat this every 3 to 4 weeks as the plant grows, adding 3 to 4 inches of soil each time, until the bed is full or the plant stops growing taller.

Hilling also keeps developing potatoes covered. Potatoes exposed to sunlight turn green and develop solanine, a toxic alkaloid. If you see green potatoes at harvest, cut away the green parts before cooking. Hilling prevents this problem entirely and typically doubles your yield compared to planting without hilling.

Watering and feeding through the growing season

Potatoes need consistent moisture, especially once flowering begins. Water deeply once or twice a week so the top 2 inches of soil stay moist. In hot weather, you may need to water more often. Mulch the top of the bed with 2 to 3 inches of straw or shredded leaves to keep soil cool and reduce evaporation.

If you filled the bed with good compost, you may not need to fertilize. If the plants look pale or growth slows, side-dress with compost or a balanced fertilizer (10-10-10 or similar) when you hill. Sprinkle it around the base of the plant, work it into the top inch of soil, and water in. Avoid high-nitrogen fertilizers, which promote leafy growth at the expense of tubers.

Recognizing when potatoes are ready to harvest

Potatoes are ready to harvest when the plant flowers or when the leaves and stems die back and turn brown. This usually happens 70 to 120 days after planting, depending on the variety. Early varieties like 'Yukon Gold' mature in 70 to 80 days. Late varieties like 'Russet' take 100 to 120 days.

You can harvest early potatoes (small, thin-skinned) as soon as flowering starts by carefully digging around the plant without disturbing it. Leave the plant in place to keep producing. For full harvest, wait until the plant dies back, then dig out all the soil and potatoes. Spread them on a tarp to dry for a few hours before storing. Store potatoes in a cool, dark place (50 to 60 degrees Fahrenheit) with good air circulation.

Common problems and how to prevent them

Potato beetles are the most visible pest. These yellow-and-black striped beetles and their orange larvae eat leaves and can defoliate a plant quickly. Hand-pick them into a bucket of soapy water, or spray with neem oil or spinosad if the infestation is heavy. Check plants twice a week during beetle season (late spring through summer).

Blight—a fungal disease that causes brown spots on leaves and stems—thrives in cool, wet weather. Space plants for good air flow, avoid wetting the leaves when you water, and remove affected leaves when ready. If blight spreads to the stem, pull the plant and dispose of it (not in compost). Powdery mildew and early blight are less serious but also benefit from good air circulation and dry foliage.

Scab (rough, corky patches on the potato skin) and soft rot (mushy potatoes) are soil-borne diseases. Prevent them by using disease-free seed potatoes, rotating beds so you don't plant potatoes in the same spot two years running, and avoiding overwatering. If you see soft rot at harvest, use those potatoes first and store the rest in cool, dry conditions.

Frequently Asked Questions

Can I plant potatoes in the same raised bed every year?

No. Potato diseases build up in soil over time, so rotate beds. Plant potatoes in a different bed each year for at least 3 years before returning to the original bed. This breaks disease cycles and keeps plants healthier.

What's the difference between seed potatoes and regular potatoes?

Seed potatoes are small potatoes grown specifically for planting and are certified disease-free. Grocery store potatoes are treated with sprout inhibitors so they don't sprout on the shelf, and they may carry diseases. Always use seed potatoes from a garden center or seed catalog.

Do I need to hill all the way to the top of the bed?

No. Hill until the bed is full or the plant stops growing taller, usually after 2 to 3 rounds of hilling. If you have extra soil left, you can hill higher, but it's not necessary. The goal is to cover developing potatoes and give roots room to grow.

How much can I harvest from one raised bed?

A 4-by-8-foot bed planted with 20 seed potatoes typically yields 40 to 80 pounds of potatoes, depending on variety, soil quality, and weather. Early varieties produce less; late varieties produce more. Good hilling and consistent watering increase yield.

What should I do if my potatoes turn green?

Green potatoes contain solanine and should not be eaten. Cut away all green parts before cooking, or discard the potato entirely if the green is extensive. Green skin means the potato was exposed to sunlight during growth. Hilling prevents this by keeping potatoes buried.