📌 Quick Summary: The Sprouting Potato Debate
- 🥔 The Problem: You go to dig up a test hill of potatoes while the vines are still green, only to find that the tubers are already sprouting new white and green shoots right in the dirt.
- 🥵 The Standard Advice: This is a stress response called “Second Growth,” usually triggered by extreme heat. The standard advice is to dig up the entire patch immediately and eat them, because they will not store well for winter.
- 🛑 Our Community’s Insight: Wait! A veteran grower from Siberia points out that rushing to harvest might be a mistake. The real trigger isn’t just heat – it is often a mix of high-nitrogen soil and sudden watering after a dry spell.
- ✂️ The Verdict: Instead of digging everything up in a panic, check out the discussion below to see why “mowing the vines” (chopping the tops off) a week before harvest might be the better trick to cure the main tubers and salvage your crop.
Good evening! Ladies, I’m going to drop a question right here in Ludmila’s diary.
Today we dug up a few potato plants. The vines are still completely green. But some of the tubers have started growing again right in the ground, they have green and white sprouts coming out of them. And it’s happening under every single plant we checked. Is this from the heat? What should I do now? Dig them all up?
NinaLug wrote:
Is this from the heat? What should I do now? Dig them all up?
This problem is called second growth (or sprouting). Yes, it’s caused by a long period of hot weather. If it’s happening everywhere in your patch, it’s better to dig them up and eat them now. Potatoes like this won’t store well for winter, and you definitely shouldn’t save them for seed potatoes either.
NinaLug wrote:
But some of the tubers have started growing again right in the ground…
This is an interesting topic. From what I understand, you’ve got “tuber chaining” (baby tubers growing off the new ones). Maybe I misunderstood? Ludmila called it second growth.
There is no perfect definition for this phenomenon, but in agronomy it’s known as chaining or secondary tuberization. People describe different causes, but the main one is the SOIL. Potatoes basically get two types of issues – infectious and NON-infectious. Personally, I’ve identified a third, sort of an “in-between” one – functional disorders during active tuber growth, which depend entirely on the “microclimate” right inside the potato hill.
We could debate this for a long time, and I don’t have time to stop and explain every detail, I’m just typing this off the top of my head in the comments, but I wanted to reply to Ninula quickly… we’ll see how it comes out…??…
NinaLug wrote:
Is this from the heat? What should I do now? Dig them all up?
In my experience, there are two main triggers here: a very “rich” soil heavily loaded with Nitrogen + moisture swings (dry periods followed by watering hot soil with cold water). This leads to a “functional disorder” in the growth of the main tuber. As a result, a sprout with a brand new baby tuber can pop right out of the eye of your main tuber, or a delayed baby tuber can form on a new stolon, looking like little peas. I won’t describe the whole biological process now, maybe I’ll return to this topic later, but I’d like to give some advice, even though giving advice is a thankless job.
Personally, I wouldn’t rush to dig them all up right now. If the vines are still looking good, there’s a small chance those baby tubers will grow just a bit more and you can use them as “new potatoes” for fancy side dishes, or feed them to the animals (birds, etc.). Out here in the country we have no problem using every little scrap for livestock, but in the city that’s probably a problem (IMHO).
If your main crop tubers have already reached a decent size, then about a week or a week and a half before you harvest, you need to mow down the vines, leaving just the bare stalks sticking up. When you do this, the main tuber will bulk up a bit more and “age” its skin, pulling nutrients back out of those little baby sprouts…
Anyway, potatoes are a fascinating crop, one of these days I’ll tell you guys more “fairy tales” about this plant… well, at least about the varieties we grow in our neck of the woods.
👨🔬 Editor’s Botanical Note: The “False Winter” Effect
Andrey hit the nail on the head regarding moisture swings. The disorder known as Second Growth (or Heat Sprouting) is essentially the potato plant getting confused by the weather.
When a potato plant goes through a period of intense heat and drought, growth stops. The tuber thinks the growing season is over and goes dormant, preparing for winter. When it suddenly rains (or you water heavily), the soil cools down and becomes flush with nitrogen again. The potato gets tricked into thinking it is “Spring,” so it breaks dormancy and starts sending out sprouts or forming a chain of new baby potatoes attached to the original one!
As Ludmila mentioned, these secondary growths rob starches from the main potato, leaving it glassy, soft, and terrible for winter storage.
