Purple Majesty Potato
Purple Majesty potato has deep purple skin and flesh with high anthocyanin content. It matures in 70–80 days and performs well across Zones 3–8 in the US.
Key takeaways
- Purple Majesty potato has deep purple skin and flesh throughout — not just under the skin — with 184 mg anthocyanins per 100g
- Plant seed potatoes 3–4 inches deep, 12 inches apart, in rows 30–36 inches apart, 2–4 weeks before last spring frost
- Purple Majesty matures in 70–80 days from planting — a mid-season variety that works in most US growing seasons
- Harvest when vines die back fully; cured purple potatoes store up to 4 months in a cool, dark, humid location
- The purple color fades significantly when boiled — roasting, baking, or air-frying preserves 60–70% of the anthocyanin content
What is Purple Majesty potato?
Purple Majesty is a mid-season potato variety with deep purple skin and uniformly purple flesh. Colorado State University released it in 2003. It contains 4 times more anthocyanins than standard russet potatoes and matures in 70–80 days.
The University of Idaho measured Purple Majesty’s anthocyanin content at 184 mg per 100g fresh weight, compared to 2–5 mg per 100g for Russet Burbank. Anthocyanins are the same antioxidant compounds found in blueberries and red cabbage.
Unlike some purple potato varieties that are purple-skinned with white or yellow flesh inside, Purple Majesty is purple throughout — from skin to core. The deep color holds through slicing, cooking (when roasted or baked), and even chips.
Purple Majesty is not a novelty. It performs as a legitimate production potato in Colorado and other Mountain West states, with yields competitive with standard mid-season varieties when managed correctly.
Growing conditions and zones
Purple Majesty grows as an annual in USDA Zones 3–8. It needs 70–80 frost-free days after planting to reach maturity. Plant 2–4 weeks before your last spring frost, when soil temperature reaches 45°F.
| USDA Zone | Planting window | Harvest window |
|---|---|---|
| Zone 3–4 | Late May–early June | August–September |
| Zone 5–6 | Late April–May | July–August |
| Zone 7 | March–April | June–July |
| Zone 8 | February–March | May–June |
| Zone 9–10 | October–January (fall crop) | February–April |
In Zone 9–10, the summer is too hot for potato culture. Grow as a fall or winter crop instead. Soil temperature above 85°F stops tuber development; potato plants survive but produce nothing useful.
For general potato planting guidance, including trench and raised bed methods, see how to plant potatoes.
Selecting and preparing seed potatoes
Buy certified disease-free seed potatoes from a reputable supplier. Grocery store potatoes are often treated with sprout inhibitors and may carry disease. Cut seed pieces to 1.5–2 oz each, ensuring each piece has 2–3 eyes.
Let cut pieces dry and callous for 24–48 hours before planting. This reduces rot in cold, wet soils. In very cold, wet soils (below 45°F), plant whole small potatoes to further reduce rot risk.
Purple Majesty seed potatoes are less widely available than Russet or Yukon Gold. Order from mail-order seed suppliers by February for spring planting. Locally, check specialty garden centers, farmers markets, and food co-ops that carry seed potatoes.
Planting method
Plant seed pieces 3–4 inches deep, 12 inches apart, in rows 30–36 inches apart. Cover with soil and leave the surface level — do not hill yet. Hilling begins when plants reach 6–8 inches tall.
Soil preparation:
- Loosen soil to 8–10 inches with a fork or broadfork
- Add 2–3 inches of compost worked into the top 8 inches
- Avoid fresh manure — too much nitrogen produces lush vines and small tubers
- pH should be 4.8–6.5; slightly acid soil reduces scab disease
Purple Majesty specific note: these tubers tend to form close to the soil surface. The dark skin requires light exclusion — any purple potato exposed to light turns green and becomes mildly toxic. Aggressive hilling is more important with purple varieties than with standard types.
Hilling schedule
First hill when plants are 6–8 inches tall: mound 4–6 inches of soil around the base, covering all but the top 3–4 inches of foliage. Second hill when plants reach 12–14 inches. Stop hilling when plants flower.
After hilling, tubers form in the mounded soil above the original planting level. The more soil you mound, the more room tubers have to develop without greening. In dry climates, mulching over the hill with straw or dry leaves reduces soil moisture loss and keeps soil temperature cooler — critical when summer temperatures push above 80°F.
Watering and fertilizing
Provide 1–2 inches of water per week. Consistent moisture during tuber set (when flowers appear) is most critical — irregular watering at this stage causes hollow heart, a condition where the center of the potato develops a brown cavity.
Water deeply and infrequently. Shallow, frequent irrigation encourages shallow root development and poor tuber formation. Check soil moisture 4 inches below the surface — it should feel moist but not saturated.
Fertilize at planting with a balanced granular fertilizer (10-10-10 or similar) worked into the soil at 2–3 lbs per 100 sq ft. Side-dress with a nitrogen source (blood meal or 21-0-0) when plants are 6 inches tall if foliage is pale yellow rather than dark green. Do not fertilize after vines begin to die back.
For companion planting strategies that improve potato yield and reduce pest pressure, see companion plants for potatoes.
Recognizing maturity and harvesting
Harvest when foliage dies back naturally, typically 2–3 weeks after flowering. Do not rush harvest. New skin on immature potatoes scuffs and bruises easily, reducing storage life.
Signs of maturity:
- Vines die back and yellow without disease pressure
- Skin doesn’t rub off when you press your thumb against a dug potato
- Flesh color is full and saturated throughout — no white ring inside when cut
Dig carefully with a garden fork, working from the outer edge of the hill toward the plant center. Purple Majesty tubers bruise and discolor when struck with a fork — dig conservatively and expect to find several tubers per plant.
A single 4 × 8 ft raised bed planted with 6–8 seed pieces of Purple Majesty yields approximately 20–30 lbs at maturity.
For timing guidance in your region, see when to harvest potatoes.
Curing and storage
Cure freshly dug Purple Majesty potatoes for 7–10 days at 50–65°F with 90–95% humidity and good airflow. Curing thickens the skin and heals minor cuts, dramatically improving storage life.
Curing setup: Spread potatoes in a single layer on newspapers or screens in a cool basement, garage, or root cellar. Keep them out of direct light. After curing, move to long-term storage at 38–42°F.
Storage life: 3–4 months in a cool, dark, humid location. Check monthly and remove any that show softening or mold — one rotting potato spreads quickly.
Cooking with Purple Majesty
Roast or bake Purple Majesty to preserve the purple color. Boiling in water leaches anthocyanins out of the flesh, turning the cooking water purple and leaving the potato significantly lighter in color.
Purple Majesty has a dry, dense texture — similar to a russet. It performs best for:
- Baking whole (400°F, 45–60 minutes)
- Roasting cubed (425°F, 25–30 minutes)
- Air-frying as fries or cubes
- Purple potato chips (slice thin, bake or fry)
It is not ideal for mashed potatoes. The dry, starchy flesh produces a gluey texture when overmixed. If mashing, use minimally — fold in butter and cream gently rather than whipping.
The purple color makes Purple Majesty striking in potato salads when cubed and tossed warm with a vinaigrette — the heat opens the cell structure and allows the dressing to penetrate. Served at room temperature, it holds color well.
Outbound resource: Colorado State University Extension’s potato production guide (extension.colostate.edu) covers Purple Majesty and other specialty varieties with variety trial data and storage recommendations for Mountain West and High Plains producers.
Sarah Mitchell is a Master Gardener and garden writer based in the Pacific Northwest. She has been growing food and flowers for over 15 years across USDA zones 7 and 8.