Potatoes , in average need about 100 days. Some early varieties might take 85 to 90 days. But you can keep them going a little longer as long as the tops and stems have not died or become woody.

Thanks seysonn -- so it doesn't sound like there is any daylength sensitivity or other similar factor that would impact that ~100-day maturation time?

YES. About 100 day(give or take 10 days or so) total time. like tomatoes, it takes a while to start setting tubers. Then it takes some time to grow the tubers to full size. Then some time to mature, i.e. to the skin to harden.
If the skin comes of easily then it is not done, Of course you can harvest some young ones(by carefully removing the soil and then packing it back).
Tubers grow on Stolons which are in ground branches. There are usually more than one tuber on each stolon, like a cluster.

There is indeed daylength sensitivity. Most potatoes grown these days are long day varieties. The original potatoes imported to Europe were short day varieties, and it wasn't until long day varieties were developed that they could be grown in northern climes where they are so important now.

Here in north central Florida I plant newly-purchased seed potatoes in mid January for a May harvest. By Labor Day, some of the unused potatoes harvested in the spring are beginning to sprout, so I plant them at that time for a December harvest (seed potatoes are unavailable in my area in late summer). Our first frost usually occurs between Thanksgiving and the first week of December, with Indian Summer persisting until just before Christmas. If I cover the potato plants for those first couple of frosts, they will be ready to harvest by mid December. That way I have (stored) home grown potatoes available every month of the year except November and April, although I can usually steal a few new potatoes during those months. I then start the new planting year in January with a freshly-purchased batch of seed potatoes to prevent the build up of diseases that will occur if I continue to replant my home-grown potatoes. Since your climate is more frost free than mine, you may want to try succession planting smaller batches of potatoes monthly through January to generate a semi-continuous harvest, especially if you like new potatoes. Also, if you have the space and inclination you should experiment with early, mid and late season varieties of potatoes planted at different times between September and January to determine what works best for you.

I don't know about day length sensitivity, but I know that potato plant does not like warm soil. That is why in places like N.FL(as coutney explained) You have to either plant them real early(spring planting) or late summer for fall planting.

SanDiego area is favorable because has cool nights that will cool off the soil even in the summer. But it is better to do it as they do it in FL.

Kira: where are you at in inland S.D.?

I'm in Santee and although it rarely freezes here, there are times when it freezes in Nov/Dec for a couple hours at night. I don't grow potatoes, but I've tried(takes up too much space for what one gets along with the less than desirable pH of our soil and water ), but all it takes is a touch of frost to kill the foliage. Mulch and makeshift covers(sheets, plastic, row covers) might just get you by in those instances. Sometimes, it doesn't freeze until Jan/feb here... so that would also help.

If you're west of the inland valleys(around Interstate 15 westward), frost isn't nearly as worrisome. Once you're east of say, Cowles Mtn, the overnight temps change just enough to cause one to keep an eye on the forecast. Also, I don't know how long you've lived here, but don't ever trust the local weather folks when it comes to temps. Wunderground.com is a much more reliable source.

Here's a pretty good planting calendar for S.D. County.

Kevin

Here is a link that might be useful: vegetable planting guide San Diego

This post was edited by woohooman on Sun, Nov 3, 13 at 11:51

Hi Kevin,

I'm north of you, on the border between Escondido and San Marcos. West of 15, south of 78. Been in the SD area for about 12 years, but only really paying attention to weather for growing purposes for the past year. Never heard of wunderground, thanks! I've noticed a ~10 degree difference for our area even between weather.gov and weather.com...

Kira: ahh.. ok. Yeah, you'll definitely need to pay attention to the frost warnings. Even though you're west of 1-15, you're right in that spot where I would think it's a lot like Escondido(which I have, over the decades, considered to have a climate VERY much like here in Santee). A few more clicks west towards Vista and you'd be in that sweet spot.

A little protection(mulch, etc) and you should be fine.

Yep. All the popular sites like you mentioned are ALWAYS too inaccurate for my liking.

Happy gardening neighbor!

Kevin

This post was edited by woohooman on Sun, Nov 3, 13 at 16:48

I'm in San Marcos, born in Escondido, hoping to retire in cool Encinitas. I lived there for awhile and loved it.
It's a bit cooler in my micro- climate as I'm right by Lake San Marcos.

This post was edited by Deeby on Thu, Nov 7, 13 at 22:13

Courtney, my place in florida is also near the 8b/9a border, and as it happens exactly on the marion/lake county border. It is a good climate for "winter" potatoes.

I'm experimenting with a number of perennial alliums this year too, including a deep-south top setting onion.

Deeby: That's a great spot for a garden. And yes, we'd all love a couple acres in Encinitas, no? ;)

Kevin

Wouldn't that be something ! The botanical garden's there too ! I never took the tour but I plan to this spring.

Well, WE'VE GOT POTATOES! Totally cheated and started poking around a bit and sure enough, baby potatoes. Hard to say if the harvest will be significant without actually dumping them all out, but at least I know we'll get SOMETHING. :-)

Second shipment of seed potatoes arrives at the end of this month... will be interesting to see what those do.

What fun ! Congrats !

.. I planted several batches throughout the month of September....
.........................
Hard to say if the harvest will be significant ..
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

As I mentioned in my first comments, potatoes need AVERAGE 100 days(from sprout to harvest) I would say anywhere from 85 days to 110 days , depending on the variety, So say if you planted in mid September, It would be 60 days at mid November: NOT ENOUGH.

I think SD area weather is good for two crops : spring and fall. For the fall you could plant them early August. For Spring , plant them in February.

Baby new potaoes are worth growing if that's all you ever get.

seysonn: I don't know if we'll get any freezes so I can leave the potatoes for another month before really harvesting. Just couldn't resist peeking :-)

ltilton: too true!!!

Sunny, ... as long as the vines are green and healthy, there is no reason to dig them. Just continue watering regularly. Keep the roots moist. Mature vines will become woody and brown, leaves yellowing.
Sure, you can reach in and pick a few young potatoes now and then. They are the tastiest delicacy . The reasons for letting grow bigger are production and longer shelf life. There is no such a thing as RIPE potato.

Can you post a picture ?

Good for you! They look lovely. Thanks to you, I've just made up my mind to add another row to my potato patch.

I'm just 1 mile east of the 15 on the border of san Marcos and Escondido at approx 1300 feet above sea level so temps are a little lower than Escondido because we get a slight ocean breeze. can I plant sprouted potatoes in early october and expect a harvest end of december?