You'd be doing a lot of unnecessary work but that is your choice. Potatoes prefer cool soil, not warm. And the only way to truly know what your soil temp is is to actually measure it. You will likely find it is warmer than you think. The real threat to direct seeded spring crops isn't so much soil temps as it is air temps AFTER they sprout, things like late freezes.

Plus potatoes take a couple of weeks to sprout so the soil will be warming some naturally during that period.

Dave

It hasn’t gotten above 53 since March 1. We have an inch of wet snow cover at the moment. I can’t imagine it’s that warm.

I’ll measure it with a meat thermometer. That’s all I’ve got but it reads down to 0F.

This is what I was going off of...

Wait... is that map saying that my soil in E. Tn. (it's colored green in that rendering) is only in the 30's F? Lol... is that a historical average, or real time data? My soil is warmer than what that map is showing.

If it's historical data, then it is inaccurate. Why? Because - as the traditional USDA zones maps have shown over the years - just in our lifetimes (for us 'middle-aged') the zones have changed at least twice. I'm in an area that was traditionally rated zone 6. We are now fairly firmly, 7a. The historical data would be skewing the temperature results downward.

It’s supooses to be “now”.

Ty hairmetal4ever. I do understand that it is applicable to 'now', but what is the data source? Is it historic averages, or is it a compilation of some group of people going out to actually measure the soil temps every week? I'm guessing it's the former. And if it is, how far back in time are they going?

Here's a map that is a bit more dynamic, and is more in line with what I'm seeing in my soil...

GreenCast

Notice on the left side of the map they have a 'Today's Average', a '5 Year Average', and a '10 Year Average'.

Instead of the 30's F from the previous map, this dynamic map is giving my soil temps at 45 F. That seems pretty close, if not right on (barring any microclimate I may have.)

Agree with rgreen. That map claims my soil is currently in the 30's but as of yesterday my soil temp measured 52 F at 6" depth. Soil thermometers are a cheap and mandatory tool for spring planting.

There is very little correlation between air temps and soil temps. Given your inch of wet snow now your soil is bound to be cool near the surface from melt water but is still warm enough to melt the snow and 6" down it is much warmer.

I'm not disagreeing with Jack that if you want to trench early for fertilizer application and to dry out the soil some - no problem - his soil is probably wetter than mine. But trenching and covering for the purpose of warming it shouldn't be necessary for potatoes.

Dave

Thanks rgreen. It does actually say 36F on that site when I punch in my zip code.

Wait, now it says 42, something updated, but the 5 and 10 yr averages say 39F.

Last year I had rain after rain after planting the potatoes. They were fine in the one garden with a little higher bed, but boy, the other area was sopping wet. It sounds good to plant deep with cool soil, but I am going to give up a bit of that to keep the early plants dryer.

I run up against summer heat by mid-June, so want to get potatoes bulking before soil temps crack the critical 80F mark, where it is said potato tubers stop growing.

It seems like I read where 85° day after day is hard on bulking up the tubers.

The map is definitely off for me as well. My thermometer measure it consistently in the 40's recently at a 4-6" depth...Week or two ago it was 50's with the mild weather we've had.

If it's cold and wet, I really don't see a reason to plant potatoes yet. Also, how late does your area tend to get cold nights? Potatoes like cool weather, but with the occasional night below 20 we normally get into late March, I wait until at least after St. Patrick's Day....Preferably a week or so afterward, weather permitting. The heat kicks in here in mid to late June, but mulched to cool the soil, my family have always been able to plant potatoes even in June. They're not as picky as people make them out to be. They just want to grow! Don't lose any sleep over it, because they certainly aren't.

here in the Detroit area (my garden is in a relatively cold spot) the ground is still frozen and covered with a few inches of snow.

Chilly forecast...

Took the temp today. Sunny and 58.

1” depth 45.4F

4” depth 37.9F