1. Irish Potatoes grow from the main stem they do not spread out. They are tubers not roots. and they do grow shallow, that is why you hill or mulch to keep them from reaching sunlight.
2. Size is somewhat dependent on conditions at the yime they start setting potatoes. Any stress during early set will reduce the number and subsequent improvement in growing conditions will result in them growing large. Ideal conditions followed by drought or other stress results in many small potatoes.
3.Irish Cobbler is an early potato compared to Kennebec but is not as early as Red Norland or Yukon Gold. also heavy nitrogen results in heavy plant growth and slow formation of tubers.

Thanks farmerdill. I will tell my uncle that RN and YG are earlier than IC. I'm pretty sure I don't have too much N in the soil, was trying to be careful about that but had no idea about timing of watering (other than I was supposed to water when I saw flower buds since that was when tubers were forming) and/or temps affecting size of potatoes.

I thought conditions were good during June, we got just over 4" of rain but it mostly came 3/4" - 1" at a time and we did have a couple of 90+ degree days in a row end of May, then 60-70's again, then a couple more 90+ days in mid June, plus insect damage/stress. What I thought was LB in early June was probably drought stress.

I really thought potatoes spread out, that's why I didn't find any a week ago, b/c I was trying not to get too close to the stems. I did mulch heavily enough to protect against greening, but would hilling with more dirt help produce more potatoes next year? As I understand, it's an old wives' tale that they produce UP the stem, they really only tend to be at the same depth (just above the seed piece?).

I left a few marble-sized ones, and am going to water now since it will be 88 tomorrow. Maybe I'll get a few more. But I planted 4.3 lbs of RN, got about 12 lbs (on bathroom scale), 2.88 lbs of YG got about 8 lbs, 2.3 lbs of RP and so far only about 4.5 lbs but they are still blooming. Is that a decent yield for new potatoes, esp. under dry conditions and a first-year farmer?

Unfortunately I couldn't produce enough for the wholesale customer who wanted them today, so I have 24 lbs to sell at market tomorrow.

Thanks

Assuming that you cut the seed potatoes, average yield is 10lbs for each lb of seed potatoes. They get much better that that in Maine and other potato growing areas, Best I have done in the south is 15-1. Of course that is mature harvest, vines completely dead. New potatoes will of course be less.

I did cut the larger seed potatoes with multiple eyes, and had read the 10-15 lbs yield figure. But had no idea for new potatoes. Just wondering what I can do better in the future. More consistent watering might be tough, though I'm sure it would help.

Pontiacs are a much later potato than the other, while individual varieties have greatly varying styles in how far the potatoes grow from the plants.
Some stay very close and some varieties they seem to go on a walkabout.
Potatoes do prefer consistent moisture, although hollow-heart is a greater problem with too much/too little watering than size.

How shallow was shallow?

I planted a couple inches deep since they already were sprouting (the ones with leaves already I let the tips of the leaves stick out of the dirt). When they all leafed out I put a couple inches more soil on so 4" basically as soon as any green leaves were showing but before plant got any height. When they were about 8" tall I had DH hill them up, I think about 4". After that I just covered with hay - ended up about a foot of hay. But nothing growing in the hay and some potatoes were 1/4" under the soil, deepest were probably 4". Not the 8" we had covered the seed pieces with - so growing much above the seed pieces (I think I might have hit 1 digging - it was cold and mushy! But that was it).

Do any of the 3 varieties I'm growing grow farther from the plant, or deeper? I only dug down about 4-6", maybe I should try deeper? Nothing close to surface a foot away from stems.

No hollow heart, no scab, no scurf - these really look good.

Noticed my uncle's plants look lots smaller than mine - at least the Irish Cobblers. Though maybe he's hilled them deep (trenched 1st so I can't tell?), he doesn't have lots of stems coming from 1 location (I average about 4?).

Depending on what you use to dig, get below the original seee at approx. three inches, and go as far out as you think the potatoes might be to avoid spiking/slicing them.

Well, that's the thing - I was feeling around last week at about a foot away from the stem(s) trying not to disturb too much, found nothing. This weekend when I starting feeling closer to the plant I found some, and yesterday I was right under the stems and found big clusters.

The Norlands look about done, if I sell all I have at market tomorrow (and neighbors this weekend) I will take my grandpa's old potato fork and try lifting the plants out. Or maybe a shovel would work better.

The YG and Pontiacs are still looking strong so will wait another week for those.

As far as stems, I was sure each piece I planted had only 2-3 eyes (unless it was a really small potato, those I planted whole), it seems like I've got a lot more stems than I remember eyes? And since I just used hay, the stems sprawl - not enough support to keep them upright, though there are a lot of almost upright ones, the plants certainly give the impression of being bushy, not low-growing and sprawling like say a cuke or other vine. In fact, they look a lot like my unpruned unstaked tomato plants - just with bigger leaves and all the flowers at the top.

I think the weather here in central Illinois has definitely affected the potato crop this year. I found very few potatoes on each vine and most growing pretty close to the surface. Some Norlands were huge with very few small ones. YG's about average size. My vines matured and dried up early, no doubt with the heat, and all are dug already. Good yield despite the growing conditions.

Do the Norlands usually grow fewer/smaller? Sounds like just what farmerdill said - if you started watering when blooming like I did, and so conditions "improved". Do they usually grow deeper and farther away from the plant for you too? Mine are getting very dry looking (leaves not stems yet), I did just water about 1/2 gal per plant yesterday, will dig them up later this week. As I said, YG and Pontiac look better and Pontiac is still blooming so I was hoping to leave them for storage potatoes but if we don't get some rain soon I'll have to dig them too. I know you need rain even more than we do.

Had *new* YG potatoes last night - OMG, I want to keep all these for myself! Better than the RN and I usually like red potatoes better. But I don' think we're going to eat 8 lbs in a week (only 3 potato eaters in the family), sold 2 lbs already, planning on taking the rest to market today so I hope we get more. Definitely planting those again!

I have not paid too much attention to my potatoes this year, other than snuffing potato bugs, but just today I was ripping a squash out of the potato patch that was too big for any good and I decided to dig some new potatoes as I will have so many it would make zero difference if some are gone.

Well, I also planted shallow, most, at most, an inch or two over the seed, covering it then with twelve, plus or minus, inches of leaves, straw or hay.

I thought it would be moist despite the near drought I have right here but found out that was a stupid thought.
There was moisture, some, below the seed but from there on up it was barely moist to just plain crunch dry.
The potatoes were producing but they came out of the ground clean as it was so dry nothing stuck to them.
I am watering now but next year I will plant them at least two inches deeper.
The odd thing is I checked moisture just two weeks ago and it was more than adequate so it does not take long to get very very dry.

At the same time the mulch over the potatoes is reduced by at least seventy five percent.

I am glan your post made me decide to have a look see.