5 Stages of Potato Development (From Planting to Harvest)
Potatoes are the world’s number one vegetable—they’re one of my favorites too! While there are over 3,000 potato varieties available, they all go through the same growth cycles. By becoming familiar with these stages, you’ll be able to provide better care and grow the best potatoes!
Potato development involves 1) sprout development, 2) vegetative growth, 3) tuber initiation, 4) tuber development, and 5) maturation. Nitrogen-rich fertilizer can be used in stages 1 and 2 for healthy foliage. Consistent irrigation is required for every stage except the last, as the plant must be allowed to wilt.
Growing potatoes is no small effort, especially when you’re just starting out. Aside from learning about the growing stages, you’ll also be able to understand what impacts their growth the most. Let’s get into it!
1. Sprout Development
Once the potato pieces are planted, they will start to develop roots and stems. This is the slowest stage in their growth. It can be sped up or skipped by planting pre-sprouted potatoes.
Average Time: 7–20 days
Tuber Growth: Not yet available
After burying the potatoes in the soil, their eyes will eventually sprout and turn into stems.
With time, these stems will rise out of the soil to follow the sunlight. Additionally, the potato will start to develop roots to absorb as much moisture as possible.
This stage can take the longest. So I suggest speeding up the process with a method called chitting. Here the cut-up pieces of potatoes are pre-sprouted before they are planted.
Regardless of how you end up going about this, the plant will not be developing any tubers during this stage.
Optimal Conditions for Stage 1
Potatoes sprout easily in acidic soil with pH values between 6 and 6.5 that’s kept at temperatures above 45°F. Water them when the top 2 inches of soil feel dry.
You may grow your potatoes in soil with pH levels as slow as 5.2. For best growth, however, plant them in slightly acidic soil–soils between 6 and 6.5 pH.
It is paramount that you plant your potatoes at the right temperatures. Plant the potatoes in soil with temperatures above 45°F and you’re guaranteed to see them sprout in no time!
It is not recommended to check for sprouting by digging or exposing the potato. Any type of disturbance will slow sprout development.
Water the soil regularly and try not to let more than 2 inches (5.08 cm) of soil dry out.
2. Vegetative Growth
Potato plants will begin showing above-soil growth and form more stems and leaves in their second stage of development. Vine-like stems will grow but tubers won’t.
Average Time: 20–40 days
Tuber Growth: Not yet available
Once the sprouts are out, the plant will start to develop roots, stems, and leaves.
This stage is also sometimes called the vining stage, as the long stems look similar to tomato vines.
During this time, they can become quite unruly and grow over a foot tall. They’ll rapidly show new growth every week, so watch them closely!
Optimal Conditions for Stage 2
Feed potato plants a water-soluble fertilizer high in nitrogen weekly to encourage more foliage.
To help encourage photosynthesis, be sure to provide your potato plants with a nitrogen-heavy liquid fertilizer. Nitrogen is excellent at promoting the growth of new leaves, which is exactly what young potato plants need.
This fertilizer on Amazon is rich with nitrogen, making it perfect to feed young potato plants.
Water your potato plant with the liquid fertilizer at least once a week and watch it take off!
3. Tuber Initiation
Potato plants that are 2 feet tall will begin forming tubers to store starch. These potatoes can be harvested after the plant flowers, but they will be small and only weigh 2 ounces or 75 grams.
Average Time: 40–60 days
Tuber Growth: Beginning
All the foliage from earlier stages will now be used to capture energy for storing starch and nutrients in the plant’s underground reserves—the very potatoes we all know and love.
Then, after about 2 months have passed, the potato plant should be around 2 feet tall and start blooming with small white flowers.
If pollinated, these flowers will produce toxic green fruit. True potato seeds can be found in these fruits and are typically used to breed new potato varieties. This is important in creating potatoes with faster maturity rates, stronger disease resistance, and more.
If harvested at this stage, the baby potatoes will be less than 2 inches (5 cm) wide and should weigh around 2 ounces (56 g). These are also known as marble potatoes.
Learn more in: How Much Does A Potato Weigh? [Measured]
If you’d rather have larger and hardier potatoes, I suggest waiting till the final stage!
Optimal Conditions for Stage 3
Flowering potato plants require a balanced liquid fertilizer with equal amounts of nitrogen, phosphorus, and potassium every week. Since potatoes are heavy feeders, the fertilizer is best applied at full strength.
Instead of using the nitrogen-rich fertilizer from before, try to use something more balanced that doesn’t just focus on nitrogen.
Feeding the plant additional nitrogen at this stage will only delay the growth of the tuber, so it’s best to lower the amount at this stage.
I highly recommend using a 5-10-10 fertilizer every week. This means the fertilizer only has 5% nitrogen, 10% phosphorous, and 10% potassium and will work great for potato plants.
4. Tuber Development
Established potato plants will continue developing tubers and storing nutrients for crop growth. The potatoes could shrink if the foliage is damaged, so they must be well protected.
Average Time: 60–80 days
Tuber Growth: On-going
Given proper care, the plant will continue storing starch and sugar and develop larger potatoes. During this period, you want to try to protect the foliage as much as possible.
Any kind of leaf damage can cause the tubers to shrink, especially frost and hail. When damaged, the plant will take away from its reserves to help repair and sustain its vegetative growth.
Potato plants can lose days of tuber development and growth if they are not protected.
Consider investing in plant covers like the one below from Amazon to help shield your potato plants from snow, rain, or excessive heat.
Aside from general protection and maintenance, they do not require any other special care. Water and fertilize them as you normally do.
5. Maturation
Photosynthesis will stop and the plant will die as the potatoes finish growing. Potatoes are most commonly harvested at this stage and often weigh between 5–9 ounces each.
Average Time: 90+ days
Tuber Growth: Complete
After 3–4 months, the potato development will finally reach completion! The above-soil growth will start to die off as the potatoes reach their full size.
The potatoes at this stage are the largest and most optimally mature, so this is when they are the most commonly harvested.
Besides that, they also have the highest starch, hardest skin, and least amount of moisture. All these make them perfect for a wide variety of things like cooking, starch processing, and animal feed.
If you’re lucky, the large potatoes should weigh around 5.4–9.4 ounces (141–255 g) each. These potatoes can be eaten right away or saved to repeat the growth cycle!
Optimal Conditions for Stage 5
Mature potato plants that are near completion must be allowed to wither. Let the plant wilt by reducing its water and halting its fertilizer application entirely.
Since this is the final stage of their development, the potato plant will not need much care. If anything, they’ll need less!
The fertilizer application should be stopped completely, and the watering frequency should taper off during this period. This allows the potato plant to die off and hasten the process for you to harvest the potatoes sooner.
3 Factors That Promote Ideal Potato Growth (Grow Big Ones!)
Key factors that encourage bigger and better potato growth are 1) soil quality, 2) fertilizer application, and 3) soil moisture.
1. Soil Quality
Nutrient-rich soil is required for cultivating high-quality potatoes. Get the soil tested and amend it with compost to ensure the potatoes have adequate nutrients to grow.
Good soil health is the number one thing you need to grow large and healthy tubers.
Before planting, it’s highly recommended to do a soil analysis. Your local Extension office can help you determine if the soil is fertile enough to grow potatoes and see what nutrients are present or missing.
This can take the most work, but trust me, it’s worth it!
Aim to create loose yet rich soil. Use plenty of compost to introduce more organic matter and beneficial microbes.
2. Fertilizer Application
Weekly fertilizer application is key to producing healthy potatoes and high yields. For best results, use nitrogen-rich fertilizer for young potato plants and a balanced fertilizer after flowering.
Aside from growing in good-quality soil, potatoes need generous amounts of fertilizer to grow and develop massive tubers.
Just remember, fertilizers act more as a booster and cannot be used to replace good soil.
In the first 2 stages of growth, nitrogen is great for encouraging more foliage. When the tubers start to develop, switch to a fertilizer with a more equal balance of NPK for tuber growth.
Pro Tip: Avoid fertilizers that include weed killers, as this can damage your plant.
3. Soil Moisture
The soil moisture for potatoes will vary from 60% to 90% depending on the development stage it is in. Higher soil moisture during tuber development is essential for producing big high-quality potatoes.
It can be tricky trying to keep up with the watering needs of potatoes, especially since each stage has specific moisture requirements.
Because of this, many growers, especially commercial ones, choose to install irrigation systems for their potatoes. Drip irrigation systems and sprinklers are the most common ones for potatoes.
Regardless of what system you use, they will all deliver a controlled amount of water to your crops and help prevent them from being under or overwatered.
Although they can take time and money to set up, they’re completely worth it.
To further make it easier for you, here’s a quick chart of how much water each stage usually requires. Naturally, this will vary depending on your soil and climate.
Potato Growing Stages | Soil Moisture Requirements |
|---|---|
Initial Planting | 70–80% Pre-planting irrigation is recommended |
Sprout Development | 65–80% Keep irrigation levels low to prevent pathogen development |
Vegetative Growth | 70–80% Increase irrigation by 0.5 inches every week until it reaches 1.5 inches |
Tuber Initiation | 70–80% Maintain consistent irrigation |
Tuber Development | 80–90% Maintain consistent irrigation |
Maturation | 60% Reduce irrigation to increase maturation |
Moisture meters are excellent at helping you identify how moist the soil is. Single-pronged meters are common, however, I highly recommend using moisture meters with two prongs for better accuracy.
What is the Nutritional Value of Potatoes?
Mature potatoes are relatively high in potassium, vitamin C, and low in sugars. Marble potatoes, or young potatoes harvested early, have similar but fewer nutrients.
Freshly harvested potatoes taste better than store-bought ones—especially frozen potatoes. But their nutritional value varies depending on which stage they were harvested.
The average potato harvested at the final stage of maturity will contain:
- 110 calories
- 620 milligrams of potassium
- 26 grams of carbohydrates
- 2 grams of dietary fiber
- 3 grams of protein
- 45% of the daily value of vitamin C
Marble potatoes tend to be lower in nutritional value since they are all much smaller.
Additionally, it may be possible for experts to develop a new potato variety that is higher in nutritional value. Currently, though, each variety generally contains the same amount of nutrients and can all be enjoyed!
FAQs
Will potatoes grow in winter?
Potatoes cannot tolerate heavy frosts so they can’t be grown outdoors in winter. However, it is possible to grow them indoors during the winter months to protect them from very cold temperatures. Provide them with plenty of sunlight to ensure tuber growth.
Are potatoes genetically modified?
The White Russet potato is the only known genetically modified commercially available potato. Despite the commonly held belief, these potatoes are safe to consume. Because of genetic engineering, these potatoes also have a longer shelf life and are less likely to bruise.
Summary of Stages of Potato Development
Regardless of what type of potato is being grown, they all have similar growth cycles. These stages include sprout development, vegetative growth, tuber initiation, tuber development, and maturation.
Potato growth can also be positively or negatively affected by their soil, fertilizer, and irrigation. Each stage has different growing needs, so it is important to provide special care for each to ensure success.
Mature potatoes are low in sugar and high in vitamin C and potassium. Smaller potatoes, or marble potatoes, harvested during the flowering stage, have fewer nutrients due to their size.
Sources
- “The Potato: Botany, Production and Uses” by Roy Navarre & Mark J. Pavek in Washington State University
- “Fertility Considerations for Potatoes” by William Lamont, Jr in Pennsylvania State University
- “Potato Growth and Irrigation Scheduling” by n/a in University of Nebraska–Lincoln
