Potato Growth Stages and Life Cycle, From Seed Potato to Harvest
Potato growth stages: a planted seed potato sprouts and breaks the surface in 2–4 weeks, leafy growth follows, tubers start forming at around 5–8 weeks, plants flower, the tubers bulk up, and they're ready to dig 70–120 days after planting.
Seed potato to shoot: sprouting
Potatoes grow from seed potatoes — small tubers, not true seeds. How one turns into a leafy shoot.
Germination timeline
- 1
Chit the seed potatoes
2–4 weeks before planting
Potatoes are grown from seed potatoes — small tubers, not true seeds. Setting them in egg boxes in a cool, bright room for a few weeks ("chitting") grows short, sturdy green sprouts from the eyes, giving an earlier start. It's optional but useful in short seasons.
→ Short green sprouts
Read the steps as text
- Chit the seed potatoes. 2–4 weeks before planting Potatoes are grown from seed potatoes — small tubers, not true seeds. Setting them in egg boxes in a cool, bright room for a few weeks ("chitting") grows short, sturdy green sprouts from the eyes, giving an earlier start. It's optional but useful in short seasons.
- Plant the seed potatoes. Day 0 Plant about 10 cm (4 in) deep, sprouts facing up, 2–4 weeks before the last frost once the soil is around 7–10°C (45–50°F). Large seed potatoes can be cut into pieces with at least two eyes each; let cut pieces dry for a day or two first.
- Roots and shoots grow underground. Week 1–2 Roots grow from the base of each sprout while the shoots push upward, fuelled entirely by the starch stored in the seed potato.
- Shoots break the surface. Week 2–4 Leafy shoots appear above ground. Cover them with soil or fleece if a frost is forecast — the foliage is easily damaged.
Seed to harvest: full life cycle
Every stage of a potato plant's life, from sowing to picking. It's drawn as a loop, the way a life cycle conventionally is — left to flower and go to seed instead of being harvested, a plant produces the seed for next year's crop.
Full life cycle timeline
- 1
Sprouting and emergence
Week 0–4
Shoots grow from the seed potato's eyes and break the surface — see the timeline above.
→ Shoots emerge
Read the steps as text
- Sprouting and emergence. Week 0–4 Shoots grow from the seed potato's eyes and break the surface — see the timeline above.
- Leafy growth and hilling. Week 3–7 Stems and leaves grow quickly. Draw soil up around the stems ("hilling" or "earthing up") when they're 15–20 cm (6–8 in) tall, and again a few weeks later — new potatoes form along the buried stems, and potatoes exposed to light turn green.
- Tubers start forming. Week 5–8 Underground stems called stolons swell at their tips into small tubers — often around the time the first flower buds appear, though some varieties rarely flower at all.
- Flowers open. Week 7–10 White, pink or purple star-shaped flowers open. Some form small green berries that look like cherry tomatoes — these hold true seed and are poisonous, so never eat them.
- Tubers bulk up. Week 9–14 The leaves pour sugars down into the tubers, which swell rapidly as starch. Steady watering now gives the biggest yield and fewer cracked or hollow potatoes.
- Ready to dig. 70–120 days from planting Early ("new") potatoes can be dug from about 70 days, often when the flowers open. For maincrops, wait until the foliage yellows and dies back, then leave the tubers in the ground about two more weeks so the skins toughen for storage.
Potato growth stages infographic
Every stage on one page — free to save, print for the garden shed or classroom, or pin.
Potato plant growth stages at a glance
Sprouting (weeks 0–4): shoots grow from the eyes of the seed potato and break the surface.
Leafy growth (weeks 3–7): stems and leaves grow fast; soil is drawn up around them (hilling).
Tuber initiation (weeks 5–8): the tips of underground stems (stolons) start to swell into small potatoes.
Flowering (weeks 7–10): white, pink or purple flowers open on many varieties.
Tuber bulking (weeks 9–14): the tubers swell rapidly as the plant stores starch.
Harvest (70–120 days): new potatoes from about 70 days; maincrops once the foliage has died back.
Seed potatoes, not seeds
Potatoes are grown from tubers rather than seeds. Each eye on a seed potato is a bud that can grow into a stem, so a whole small potato — or a piece of a big one with two eyes — becomes a new plant identical to its parent. Use certified seed potatoes rather than ones from the shop, which may carry disease or be treated to stop sprouting.
Potatoes do make true seed, inside small green berries that sometimes follow the flowers. Those berries are poisonous, and the seeds inside grow into plants unlike their parent, which is why breeders use them and gardeners don't.
Why potatoes are hilled
New tubers form along the buried part of the stem, so drawing soil up around the plants gives them more room to form and keeps them covered. Potatoes exposed to light turn green and build up solanine, a bitter, toxic compound — green patches should be cut away, and very green potatoes thrown out.
Hill when stems are about 15–20 cm (6–8 in) tall, leaving the top few leaves showing, and repeat once or twice a few weeks apart. Deep mulch or growing bags work the same way.
Frequently asked questions
- How long do potatoes take to sprout after planting?
- Usually 2–4 weeks for the shoots to break the surface — quicker with chitted (pre-sprouted) seed potatoes and warmer soil.
- How long do potatoes take to grow?
- Early or "new" potatoes can be dug from about 70 days after planting; maincrop potatoes take about 90–120 days.
- Do potatoes need to flower before harvest?
- No. Flowering is a rough sign that tubers are forming, and new potatoes are often ready around then, but some varieties barely flower at all. Check by gently digging around one plant.
- Are potato berries edible?
- No — the small green tomato-like fruits that sometimes follow potato flowers are poisonous. Remove them if children are around.
- How do I know when potatoes are ready to dig?
- For new potatoes, when the plants flower or about 10 weeks after planting. For storage potatoes, wait until the foliage yellows and dies back, then leave them in the ground about two more weeks so the skins set.