Soil temperature.

[Worth1]

I have been reading my soil temperature in the same spot for several days now.
While doing this I have been observing the growth of the plants.
They were doing so so at around 62F until it came a cold rain the other day.
This rain cooled the soil down a wee bit and the growth slowed down.
Today I noticed over night the tomatoes started taking off and I took another reading.
The soil temp today is 68F
Now my thermometer may be reading 3 degrees on the hot side and there is no way to calibrate it.
I cant find my good ones so I am using my electronic meat thermometer.

There are also two Black Prince tomatoes that are dark green that aren't growing like the others.
But today they are just starting to show some better growth.
The tomatoes that seem to show the best ability to take up nutrients in the cooler soil are San Marzano.

Just thought I would do this so folks could get a better idea of how the plants will do in differing temps.

One last note, I have been testing the roots also and from the time I put the plants out they have been growing.
The soil I think was 55F when I put everything out.

I am guessing that in the next two days if it doesn't rain the soil will be up to 70F or more.

I also have pinto beans starting to break surface.
Worth

[ScottinAtlanta]

Worth, how deep down do you measure? I have one of those great laser thermometers, but am not sure how deep is relevant for toms. 3 inches?

[Worth1]

Originally Posted by ScottinAtlanta

Worth, how deep down do you measure? I have one of those great laser thermometers, but am not sure how deep is relevant for toms. 3 inches?

Let me go look I will be right back.---------------
Okay I'm back, I have a 6 inch probe stuck in the ground 5 inches.
And the temp has jumped up to 69F

I always measure in the same spot every day.

Worth

[AlittleSalt]

At 4 inches deep, where I'm about to plant a tomato plant, my soil temp is 67F.

Three days ago, it was 62F

[Gardeneer]

Normal ground temperature ( from the heat coming from the center of Earth) is somewhere in 55 to 65F range , depending on the geology of a given location. This temperature is normally measured at about 2 feet depth.

What this all means is that if you insulate the soil (so there is no heat loss or gain from the air and Sun) your soil temperature cannot go mush higher than 55 to 65F. What makes the soil cool in winter month iis the heat loss to the air and what make it warm in summer is the heat gain from sun and the air. So the higher soil temperatures come mostly from the above not below. So down south, if you want to keep the soil cooler, you need to insulate it. MULCH is the material for it. Also watering the plants with cool water can help.

Different vegetable can grow/thrive normally at certain soil temperature range. I have studied the effect of warm temperature on potatoes (first cousins of tomatoes). At a soil temperatures around 75F and higher they will shut down growing/setting tubers. The same way tomatoes shut down. It is not just the air temperature that causes blossom drop but also the soil temperatures might play a role too.

I knw that potatoes sprout in a fairly cold soil temperature. In GA I used to plant them about 3 weeks before LFD. So tomatoes being the next cousins of potatoes can do fine with soil temperatures of 55+. There will be a temporary transplant set back/adjustment (call it shock) until they resume normal growth in the new environment.

BTW: I measred my soil temperature yesterday. It was around 52F under black plastic. In 2 to 3 weeks (i.e. after LFD) it should get close to 58F.

[Worth1]

Originally Posted by Gardeneer

Normal ground temperature ( from the heat coming from the center of Earth) is somewhere in 55 to 65F range , depending on the geology of a given location. This temperature is normally measured at about 2 feet depth.

What this all means is that if you insulate the soil (so there is no heat loss or gain from the air and Sun) your soil temperature cannot go mush higher than 55 to 65F. What makes the soil cool in winter month iis the heat loss to the air and what make it warm in summer is the heat gain from sun and the air. So the higher soil temperatures come mostly from the above not below. So down south, if you want to keep the soil cooler, you need to insulate it. MULCH is the material for it. Also watering the plants with cool water can help.

Different vegetable can grow/thrive normally at certain soil temperature range. I have studied the effect of warm temperature on potatoes (first cousins of tomatoes). At a soil temperatures around 75F and higher they will shut down growing/setting tubers. The same way tomatoes shut down. It is not just the air temperature that causes blossom drop but also the soil temperatures might play a role too.

I knw that potatoes sprout in a fairly cold soil temperature. In GA I used to plant them about 3 weeks before LFD. So tomatoes being the next cousins of potatoes can do fine with soil temperatures of 55+. There will be a temporary transplant set back/adjustment (call it shock) until they resume normal growth in the new environment.

BTW: I measred my soil temperature yesterday. It was around 52F under black plastic. In 2 to 3 weeks (i.e. after LFD) it should get close to 58F.

I thought potatoes liked hot soil to set tubers.
That's why Texas is the potato capital of the USA.

Worth

[Gardeneer]

Originally Posted by Worth1

I thought potatoes liked hot soil to set tubers.
That's why Texas is the potato capital of the USA.

Worth

I though Idaho is the Potato capital.

I have heard of Texas yellow roses but not potatoes.
In Georgia tomatoes are finished by late June. Then you can plant fall crop in August. It is more like planting tomatoes in some part of Texas.

[aclum]

Hi,

This is a timely topic for me as I've just started planting out in raised beds and have been planning on laying down some heavier (underlayment?) weed block fabric in the 3' wide dirt pathways between the beds. I'm in a wheelchair and also have respiratory issues so I'm hoping to get a relatively even surface for the wheelchair plus keep down the dust. And the weedblock is a relatively cheap and easy to install option for me.

It just dawned on me today that maybe the black fabric would heat things up too much for the tomatoes here in the Central California Valley where it can get pretty hot in the summer. The beds are 3' or 5' wide with drip irrigation under perforated reflective silver mulch over the soil and aluminet shade cloth overhead. So the ground temp in the beds themselves should tend to stay relatively cool in hot weather - especially as the plants grow and begin to provide more foliage cover.

For those of you who know about such things..... would the black fabric on the paths have a negative impact on plants in the raised beds (the plants are about a foot back from the edge of the beds away from the paths). How far down into the soil directly beneath the black weed block would the added heat extend (the soil is pretty well packed clayish in the pathways)?

BTW, I'm assuming the weed block material I plan to use will hold up to traffic.....

Anne

[Stvrob]

Originally Posted by Worth1

I thought potatoes liked hot soil to set tubers.
That's why Texas is the potato capital of the USA.

Worth

I wonder....if you took an old window A/C unit and unrolled the evaporator coil and buried it below your potato bed, could growers in the South extend their season enough to grow large mature potatoes? You could swap the thermostat to an inground sensor to keep an even 60℉ under the mulch.

[Worth1]

Originally Posted by Gardeneer

I though Idaho is the Potato capital.

I have heard of Texas yellow roses but not potatoes.
In Georgia tomatoes are finished by late June. Then you can plant fall crop in August. It is more like planting tomatoes in some part of Texas.

http://www.google.com/url?sa=t&rct=j...88528373,d.eXY

[drew51]

I must say I have never seen a potato from Texas! Are they yellow?
I tried taking a ground temp, but it was rather difficult. I need to wait a few days.

[Worth1]

Originally Posted by drew51

I must say I have never seen a potato from Texas! Are they yellow?
I tried taking a ground temp, but it was rather difficult. I need to wait a few days.

They have huge farms around Dalhart Texas.
Grow all kinds of potatoes.
The elevation is 3,983 feet. almost 4,000 feet.
It is only about 100 miles from Colorado which that part of used to be part of Texas.

Worth
Dalhart.JPG

[AlittleSalt]

Originally Posted by Worth1

http://www.google.com/url?sa=t&rct=j...88528373,d.eXY

We buy these only. I won't buy potatoes from anywhere but HEB.

[Worth1]

Originally Posted by AlittleSalt

We buy these only. I won't buy potatoes from anywhere but HEB.

Salt thats what I buy too.
The big russets are huge.
They are fantastic.
I try to buy made or produced in Texas first and then The US.

Worth

[drew51]

We are kind of far away with Idaho inbetween. I don't consume that many myself, my doctor won't let me! I have to limit carbs. I bet some are sold here though. Although Idaho are so good, all I buy.
Yeah I'm waiting for ground temps to warm up for plant out. Currently waiting for it to get above freezing on the first day of spring so I can put my peppers in the cold frame! I get about 20 degrees warmer in the cold frame so watching the current temps, when they hit 40F I can put the plants out. High today is 55F currently it is 34F yeah above freezing! I can put my germinated onions out!