Why do red potatoes have sprouts?

Red potatoes, with their vibrant red skin and white flesh, are a tasty and nutritious potato variety. However, like all potatoes, red potatoes can develop sprouts – those small buds that protrude from the potato’s surface.

What are potato sprouts?

Potato sprouts are small buds that form on the potato and grow into vegetative shoots. Inside each potato is a dormant vegetative bud known as an “eye”. When the conditions are right, these eyes will begin to grow, forming sprouts. Sprouts are a sign that the potato is ready to grow a new plant.

On a healthy, whole potato that is left to sit for too long, sprouts will begin to emerge from the eyes across the surface of the tuber. This is the potato’s way of reproducing – attempting to grow new potato plants. If left under the right growing conditions, those sprouts can develop into full potato plants.

Why do the eyes on potatoes sprout?

Potato eyes sprout when the tuber is exposed to certain environmental conditions that activate hormonal pathways leading to sprouting. The key factors involved in potato sprouting are:

  • Carbohydrate content – Potatoes contain starch which is broken down into sugars that fuel the sprouting process.
  • Temperature – Warmer temperatures between 10-25°C stimulate sprout development.
  • Light exposure – Light exposure, even at very low levels, triggers hormonal pathways leading to sprouting.
  • Time – Given enough time, potatoes will begin to sprout as dormant eyes eventually activate.

When potatoes are left sitting at room temperature in the light, the eyes detect the favorable conditions and begin to grow sprouts as a way for the tuber to propagate itself into a new plant.

Why do red potatoes sprout?

Red potatoes sprout for the same reasons as all other potato varieties – the tubers react to environmental cues by activating dormant vegetative buds that develop into sprouts. The traits that make red potatoes sprout include:

  • Starch content – All potato tubers, including red potatoes, contain high levels of starch that can be broken down into sugars to fuel sprouting.
  • Eyes – Red potatoes, like other potatoes, have dormant buds called eyes scattered across their surface that give rise to sprouts.
  • Growing conditions – When left in warm, light conditions, the dormant eyes on red potatoes are triggered to begin sprouting.

So while the red skin and white flesh are defining features of a red potato, their basic biology and sprouting tendencies are similar to all potato varieties.

At what point in storage do red potatoes sprout?

Red potatoes can begin sprouting any time from 2 weeks to 3 months into their storage period:

  • Early sprouting 2-4 weeks after harvest occurs if potatoes are cured at warm temperatures above 10°C which accelerates sprout development.
  • Sprouting 2-3 months into storage is typical if potatoes are cured and stored properly below 10°C.
  • By 3-5 months most potatoes will have begun to sprout even when stored at ideal cold temperatures.

The exact sprouting time depends on storage conditions, the potato’s starch content, and natural dormancy period. Early sprouting can be avoided by proper curing and cooling of potatoes immediately after harvest.

What causes red potatoes to sprout early?

Some common causes of early sprouting in red potatoes include:

  • Improper curing – Curing at temperatures above 10°C hastens sprouting.
  • Temperature fluctuations – Shifting storage temperatures can initiate sprouting.
  • Light exposure – Any light exposure activates sprouting pathways.
  • Physical damage – Cuts and bruises remove sprout inhibitors.
  • High respiration rate – Immature, stressed, or diseased tubers respire faster and sprout earlier.

Ensuring red potatoes are cured and stored properly immediately after harvest can maximize dormancy and prevent premature sprouting.

At what temperature do red potatoes sprout?

The ideal temperature range for red potato sprouting is 10-25°C:

  • Minimum temperature – Potatoes sprout poorly below 10°C as low temperatures inhibit sprout growth.
  • Optimal temperature – The fastest sprout growth occurs between 15-20°C.
  • Maximum temperature – Temperatures above 25°C cause abnormal elongated sprouts.

Storing red potatoes below 10°C and close to 0°C suppresses sprouting while warmer temperatures between 15-20°C encourage rapid sprout development.

Can sprouting be prevented in red potatoes?

There are several strategies that can be used to prevent or delay sprouting in red potatoes:

  • Cold storage – Storing potatoes at 0-4°C can prolong dormancy and delay sprouting for months.
  • Maintain humidity – Keeping humidity around 95% prevents dehydration and associated increases in sprout growth.
  • Controlled atmospheres – Storing potatoes in low oxygen or high carbon dioxide environments inhibits sprouting.
  • Sprout inhibitors – Applying chlorpropham (CIPC) prevents cell division needed for sprout growth.
  • Packaging – Storing potatoes in complete darkness prevents light-induced sprouting signals.

While sprouting can be reduced, it cannot be prevented indefinitely in whole red potatoes. The most effective approach is cold storage close to 0°C immediately after harvest.

Are sprouted red potatoes safe to eat?

Sprouted red potatoes are still safe to eat as long as they are otherwise firm and free of mold, dark spots, or green patches:

  • Trim off any sprouts or “eyes” since they can be toxic in large quantities.
  • Cut away any green skin which indicates presence of toxin solanine.
  • Cook sprouted potatoes thoroughly which destroys solanine toxin.
  • Avoid eating potatoes with extensive sprouting or very long sprouts.

Sprouting alone does not make red potatoes dangerous to eat. Only if sprouting is accompanied by signs of decay, mold, or greening should sprouted potatoes be discarded.

Nutrition of sprouted red potatoes

The nutritional value of red potatoes is not significantly affected by sprouting:

  • Starch content – There is little reduction in total starch as only small localized amounts are utilized for sprouting.
  • Vitamins – Levels of vitamin C and B-complex vitamins remain unchanged.
  • Minerals – Mineral content is not impacted.
  • Toxins – Sprouting alone does not increase glycoalkaloids like solanine.

Trimming off sprouts and any green areas on the skin removes any toxins so the remaining potato retains its full nutritional value.

Changes during sprouting

As red potatoes sprout, there are some subtle changes underway inside the tuber:

  • Conversion of starch to sugars around the eyes to fuel sprout growth.
  • Localized tissue softening around developing sprout buds.
  • Potential production of toxins like solanine if greens develop.
  • Increased respiration and aging of the potatoes.

However, these changes are confined to small areas around each sprout. The interior flesh of the potato remains unaffected and perfectly edible.

Signs of spoiled sprouted potatoes

While sprouting alone does not spoil red potatoes, extensive sprouting combined with these signs indicate spoilage:

  • Wrinkled, shriveled skins
  • Soft, mushy consistency
  • Darkening flesh
  • Strong musty odor
  • Mold growth
  • Rotten spots

Potatoes exhibiting these traits in conjunction with sprouting have likely begun to break down and spoil through bacterial or fungal action and should be discarded.

Uses of sprouted red potatoes

Sprouted red potatoes with minor sprouting are still good to eat. Some of the best uses include:

  • Boiled / Steamed – Cooking whole helps soften the sprouted areas.
  • Mashed – Blends well to hide small sprouts.
  • Baked potatoes – Baking hides mild sprouting.
  • Home fries – Cutting into pieces removes eyes and sprouts.
  • Soups – Blending into soups utilizes the whole potato.

Heavily sprouted potatoes with long sprouts should be avoided. Trimming off eyes and sprouts before cooking improves the texture and taste of sprouted red potatoes.

Storing potatoes to prevent sprouting

To prevent or delay sprouting in red potatoes:

  • Cure freshly harvested potatoes for 1-2 weeks at 10-15°C with high humidity.
  • Move potatoes to a cold, humid storage area at 0-4°C in complete darkness.
  • Inspect potatoes periodically and remove any sprouting tubers.
  • Maintain bins free of excess moisture to avoid rots.
  • Consume within 1-3 months for best quality.

Ideal post-harvest curing followed by cold, dark, humid storage gives red potatoes the longest dormancy and high quality.


Red potatoes sprout for the same reasons as all potatoes – exposure to the right combination of hormones, light, warmth, moisture, and time triggers dormant eyes to begin growing. While unsightly and undesirable, mild sprouting alone does not make red potatoes inedible or hazardous. Trimming sprouts and preparing the potatoes well can still yield tasty dishes. Storing freshly harvested potatoes properly can maximize dormancy and quality but sprouting will eventually occur in whole tubers over months. Understanding the biology behind potato sprouting allows for informed decisions on when sprouted red potatoes can be safely consumed.

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