How Long Does It Take Potatoes to Germinate
There are several factors I’ve noticed that contribute to the amount of time it takes a seed potato to germinate and for a sprout to emerge from the soil.
Those factors are the temperature, green sprouting, soil pH, soil drainage, and the depth of planting.
While I’ve grown potatoes from true seeds before, it’s much less common. In this article I want to share my germination results using seed potatoes.
Potato Germination Time Short Answer
Potatoes usually germinate and emerge from the soil 3 to 6 weeks after planting; however, factors such as soil temperature, planting depth, soil pH, and green sprouting can all affect this timeline. I’ve also had potatoes take over 45 days to emerge from the soil depending on conditions.
Some potato varieties will also emerge sooner than others. I’ve found that waxy, yellow potatoes emerge before red or russet varieties.
For a more in-depth answer, keep reading on.
How pH Affects Germination
When I’ve grown potatoes in the past, they’ve germinated fairly well in slightly acidic soils and neutral ones, but alkaline soil seems to slow down not only germination but also the plant’s growth as well.
I’ve found that potatoes germinate and sprout best in soils between 5.8 and 6.5, although they will tolerate soils outside of that range.
How Green Sprouting Affects Germination
Green sprouting or chitting is a common practice among home gardeners, but seldom done on scale at farms from what I’ve heard.
Green sprouting produces short stubby sprouts on the eyes of the potato which help it germinate and grow into a plant faster once planted in the earth.
When I’ve chitted potatoes prior to planting in 70° to 80°F air temperatures it usually takes 14 to 25 days for the potato to green sprout at least 1/2 inch.
I ran an experiment this year with store-bought potatoes to see how they would fare too. Here were my results.
Trader Joe’s Organic Yellow Potatoes took 14 days to sprout multiple green sprouts.
Trader Joe’s Organic Red Potatoes took 22 days to green sprout.
Trader Joe’s Organic Russet Potatoes took 25 days to green sprout.
How Soil Temperature Affects Germination
Perhaps one of the biggest factors in how fast potatoes germinate is the soil temperature. When planting a seed potato, you’re waiting for two things to happen - for the sprout to emerge and grow leaves and vines which will provide energy to the plants, and for root growth to occur.
Once those two things have happened, tubers can also start to initiate later.
Root growth can occur at soil temperatures between 50°F and 95°F; however, it will be most active between 60°F and 70°F.
Leaf and vine growth can occur at soil temperatures between 45°F and 85°F, but they do best at temperatures between 70°F and 80°F.
This is why I love planting potatoes in the fall because the soil is warmer and I don’t have to wait as long for growth to begin.
How Planting Depth Affects Germination
Planting depth matters mostly because soil temperature matters. For example, when I plant potatoes at the end of August, I usually plant them deeper because the weather is still pretty warm. The deeper I plant them, the cooler the soil is.
This August I planted several potatoes at different depths to test this. Here were the results.
The seed potatoes planted at 3” deep took over 30 days to emerge.
The seed potatoes planted at 6” deep emerged around 26 days.
The seed potatoes I planted at 12” deep only took 23 days for all of them to emerge.
They were all planted in the same raised bed with the same soil and climate conditions. None of them were green sprouted ahead of time and each had an equal number of eyes for sprouts to begin. The only difference was the depth.
How Long Does It Take For Potatoes to Germinate
This year I tested this with my fall potatoes. I planted a group of potatoes and tested the soil temperatures three times per day while carefully monitoring soil moisture as well.
In soil temperatures that ranged from 69°F to 96°F with an average temperature of 84°F (we had a 3-day heat wave a week and a half after I planted, go figure), it took my seed potatoes anywhere from 18 days to 26 days to germinate and emerge from the soil.
The yellow potatoes germinated and emerged the fastest, followed by the red potatoes. The russet potatoes took the longest to germinate.
I found this to be in line with most other advice I’ve read that says potatoes take anywhere from 3 to 4 weeks to germinate and emerge from the soil.
Do Potatoes Germinate Faster in Soil or Air
Green sprouting potatoes in an egg carton with partial light exposure, temperatures around 70°F, and high humidity has always been faster than planting potatoes in the soil and waiting for them to sprout underground.
Germinating a potato in the air has always been faster than in the soil for me.
When I germinated some Yukon Gold seed potatoes, it took 13 days for them to grow sprouts when I kept them in an egg carton with partial light at around 80°F.
On the other hand, I placed some non-sprouted potatoes in the ground and it took 18 days for them to sprout underground.
So while sprouting potatoes before planting does take less time, I don’t know if it’s always worth it for the sake of speed. There was less than a week difference between the two when I tested it.
Potato Germination Recommended Reading
How to Plant Potatoes
