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Posted by nated 7 (My Page) on
Sat, Jun 22, 13 at 8:25

Howdy, this is my first grow attempt at potatoes. i planted the Kennebec variety. I can say potatoes are no where near the high maintenance, daily pest inspection, of squash and zucchini. i'm in OKC. What am i looking for or what is the signal to harvest potatoes?? with what little effort these took, provided i get a return, i could see putting these in again. the black tubing is the end of my drip irrigation. i ran it over there, planted a squash beside the drain end. the squash bugs haven't caught on yet. I'm looking for them and eggs with soap in hand. thanks much.

Follow-Up Postings:

RE: potatoes

Hi Nate,

There are several ways to know when potatoes are harvest-ready.

First, consider the DTM for the variety in question. For Kennebec it is 80-100 days and in our climate I consider it a late potato. Of all the varieties I grow, it normally is the last one I harvest. I've already dug up the other 8 varieties I planted, finishing them yesterday, but the bed with the Kennebecs doesn't look ready to dig yet.

Secondly, most of the time, the plants begin to yellow and die back when the tubers are as mature as they're going to get. This can happen anytime from May to July, depending on when you planted your potatoes (normally in February or March) and depending on the variety. Often, a first-time potato grower will think their plants are sick when, really, they're just dying back because they've done their job and produced the tubers.

Potatoes can be harvested at any size at which they are usable, even if the foliage isn't yellowing and dying back. It is just that leaving them growing for a longer period of time gives you more potatoes and larger potatoes. Lots of people 'rob' a few early potatoes from the plants by gently digging in the soil and finding and removing small potatoes to eat as tender new potatoes while not damaging the plant. Then they harvest the rest of the potatoes after the plant begins to die back.

Any time that you want to figure out if there are potatoes down there underneath the plant that have reached a usable size, just dig gently in the soil around the plant to check the size of the potatoes.

Those of us in southern Oklahoma have been digging potatoes for 2 or 3 weeks now. I don't know if anyone in other parts of the state is harvesting any yet. For most varieties, potatoes are a nice usable size 90-120 days after the seed potatoes were planted, although rainfall and temperatures can affect how quickly or how slowly the tubers are ready.

There are different ways to harvest. If you only grew enough for short-term eating over the next couple of months, you can cut the foliage off and dig the potatoes any time you choose. If you grew a lot and want to use some for more long-term storage, cut off the foliage and let the potatoes sit in the ground for another 3-6 days before you dig them. This allows their skin to thicken up and get tougher. The tougher skin will protect the flesh of the potatoes and allow them to last longer in storage.

Once the weather gets really hot, leaving the potatoes in the ground too long can be risky if you've had lots of rain and the soil is moist. Often. the combination of lots of moist soil and extreme heat cause the potatoes to rot. Some years I see quite a bit of rot, sometimes I see none at all, even in a wet year. Most of my rain here has fallen since mid-May and I am seeing more rot than I've ever seen before, but it is not a lot overall as a percentage of the crop.

In the fall, you often can leave potatoes in the ground and harvest them as needed as long as the soil isn't too wet. Try that in the summer, especially a wet summer, and you may find grubs and wireworms, among other pests, eating the potatoes underground.

To dig them, stick your shovel or a spading fork into the ground about a foot away from each plant, lift up and, if the foliage remains attached to the plant, pull the foliage up with one hand while lifting the soil/potatoes with the shovel or fork. It is pretty easy once you get the hang of it. After you've removed all the potatoes you have found, dig a little deeper to make sure you haven't missed any. In a normal year with average weather conditions, you'll often find 4-6 large potatoes underneath each plant and several smaller ones as well. This has been a really good year and I have found 8 large potatoes underneath some plants, with oodles of little ones. With one variety I'd only find 1-2 large potatoes, but they were gigantic. For some reason, those plants made fewer potatoes but the potatoes were really big.

Be sure to clean up all the leftover plant debris, including any partially rotted potatoes culled out of the pile of usable ones. Throw them away or compost them. Cull piles of potatoes sitting around on the ground can become a breeding ground for serious disease.

Kennebec produces heavily and often produces potatoes that are quite large.

Because it is getting so hot now, your potato plants will be happiest when mulched very well. I have mulch 12" deep on my Kennebec bed, and because the Kennebecs are in a bed raised 16" above grade level, even the exterior of the bed has grass clippings piled as thick and deep as I could get them---all in an effort to keep the soil cooler.

Potatoes start forming tubers about 3 weeks after you see plant foliage emerging from the ground. The plants set and size up the tubers best while daytime highs are in the 60s and 70s and nighttime lows are in the 40s-50s. Once your soil temperature is consistently hitting 85 degrees, the plants stop setting new tubers and the ones that you have do not enlarge a great deal more. So, once soil temperatures are really hot, there is not a lot to be gained by leaving the plants in the ground longer.

I have dug around 300 lbs. of potatoes in the last week or so, and still have the Kennebecs left to do. I suppose if I had any sense I'd be out there digging them today, but just couldn't get motivated to dig this afternoon in the heat. Don't wait too long before you check your potatoes to see if they are large enough to harvest and use. If your soil is moist, then with the kinds of temperatures we're seeing now, rot could set in pretty quickly. They're a cool-season crop, although technically, we harvest them after the cool season essentially has ended.


RE: potatoes

We start harvesting a few new poataoes when the plants bloom and dig the entire crop when the plants have died about 3/4 of the way back, so we can still find the base of the plants. For us, planting in midMarch, potato harvest is usually close to the 4th of July. They'll have to hurry this year to be died back by then. Yours don't look like they are ready yet.

RE: potatoes

If the Mesonet three day average 2 inches vegetative covered soil temperature gets to 85 degrees i'm gonna harvest. i'd like to see a little die back. 4th of July though will be about as long as i can leave them alone. many thanks to all for all the advice.

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