I planted three varieties of potatoes on April 1. German Butterball, Kennebec, and Desiree. A few weeks ago, the plants started yellowing a bit and getting crispy edges. I feared late blight, but discovered it was actually potato leafhopper, which I sprayed for, and they got new, darker green growth. At this point, although the vines are long and lying flat, they’re as green as ever and show no signs of dying back.

I dug some delicious new potatoes around July 10, but at that point only the Desirees had sized up well, many were as large as “grocery store size”. The Kennebec and German Butterballs were all golf-ball sized at best at the time.

I wonder if I should just let them go a bit, or cut the vines down, give them a couple weeks to cure their skins, and dig them. Our soil temps are 75 – 80F even at tuber depth, so I don’t know if I’ll get much more tuber growth due to the hot soil, unless the four days of rain we had cooled it off a bit.

Any thoughts?


I would only dig enough to eat now. They can be left in the ground until just before the soil freezes here in the North. They look like they are still growing fine.

they grow kennebecs here commercially. i would let them grow too much longer or you could wind up with big hollow ones. they plant in mid may and harvest in mid sept. here but we are a lot colder than you are…

Those aren’t nearly ready to go

I’m in your zone and have grown all of the potatoes you have in the ground. My potatoes have just stopped blooming. I leave mine in the ground till the stems are brown, then dig. I will get bigger and better potatoes that way.


I’ve read it from multiple sources that the tubers stop bulking when the soil temperature gets above about 75 or 80°, and it’s up there.

How far down?

Good question, never heard about soil heat before either, interesting.

This is one reason I use straw to cover my potatoes, it keeps the soil cool and moist

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So in the ten hours since I took the photo, a large chunk of the plants (on the middle of the patch) are wilting, but not entirely.

Parts of the plants past a soft, blackened, hollow point. I’m guessing rot from all the rain we got or possibly European Corn borer.

I dug one plant of German butterball, one that was heavily affected. Nice yield. Not the biggest tatters but 1.5 lbs - not bad from one plant.

However, I now wonder if I should just go ahead and cut the plants down, let the tubers cure a couple weeks, and dig.


18# of Russets

I pulled much of the bed today. Some vines were still green, so I left those, and there are certainly more tubers still in the ground - there always are - which I’ll dig later. But the soil was unusually soft and friable, and these pulled out easily w/o the stolons breaking off.

Some nice bakers this time, and almost no mutants.

Fingerlings aren’t ready yet, which vexes me - I like them best for summer potato salad.


Oh boy, Lous you lucky girl! I only planted Russian Butter this year and only one row. Those are fabulous!

Odd thing is - I don’t know what variety they are. I get them from a local garden store, and they say they don’t know. I have to get them to ask when they order for next year.

Kennebecs. A little scab, but got 15.8 lbs from a 10’ row (one pound of seed potato) after losses (some rotted at Center of row-too much rain) and some idiot (me) sliced several while digging. Adjusting for losses, my true yield was closer to 20 lbs per pound.


Ironically, the Kennebec plants started noticeably dying back within a couple days after my last post.

They were pretty dry today so I dug them. Just a few wisps of green left here and there. Probably should’ve let them go longer, but the skins seem fairly mature.

The German Butterball plants are still deep green.

My butternalls are green too!

Here are some (I’ve been eating them…) of the potatoes I’ve dug during the last week. There are at least 8 different kinds in the pic. So far, I think I like Purple Peruvian and Natasha.


Information on Peruvian Purple from OSU:


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FIngerlings are finally getting ready - I pulled enough for a potato salad yesterday