I've planted potatoes before but order usually doesn't arrive till approx. May 1st. Seemed to me that it was too late because St. Louis, Zone 6, gets very hot very quickly in May and high heat impacts potato size (or that was my excuse LOL). This year ordered a special earlier delivery and potatoes arrived yesterday (Russian Banana Fingerlings). I see some advice that says you can plant 3-4 weeks before last frost date. But...if I am able to cover in case of freak snow, which would likely melt very next day, can I get away with planting the first or 2nd week of March?
Anybody use soil temps to plant or is everybody just going with 3-4 weeks before last ave. frost date?
I do have southern facing area available that is full sun and seems almost a microclimate 1 zone warmer, according to my results there.
Here in Florida, I plant my potatoes around the end of January--about 6 weeks or so before the last expected frost--and have good luck with them. As far as ordering potatoes from a mail order seed company, I have never had good luck with that. Your best bet would be to go to a local feed and seed store. They will carry the best potatoes for your area.
My red potatoes are about a foot tall now. I do plant them early (dec or jan) and cover up the small plants with leaves from the yard. I pile them on heavy and then simply rakes them away after the cold weather. They were old sprouters from my kitchen and I also have a big problem with the seed companies which always send too late.
According to the Illinois Extension Department: "Maximal tuber formation occurs at soil temperatures between 60° and 70°F. The tubers fail to form when the soil temperature reaches 80°F. Potatoes can withstand light frosts in the spring, although there may be some not-pretty-stem damage."
According to the Kentucky Extension office: "The best time to plant potatoes is about 6 weeks before the last average frost. In zone 6 for early potatoes that is from March 1 to April 10; for the late crop, June 15. The late planting will generally give a lower yield than the spring planting."
On a personal note: I spent the majority of my life in the KC, MO and Omaha, NE area and we would always shoot for a St. Patrick's Day planting.
It's best to use uncut seed potatoes. If you have to cut them, be sure to use a clean knife and then left them air dry to scab over before planting to help cut down on possible disease.
Thanks for soil temps:) I remember reading somewhere about high temps but never a low temp. Looks like we are right in the range to plant. Now all I need to do is find more space in the garden. I never seem to have enough space!