Leaving Tomato Plants Out?

AlittleSalt · March 7, 2015

The ideal time to plant out tomato plants for my area is supposed to be as early as Mid-March. Which got me to thinking about eventually leaving the plants outside at night while hardening them off.

This week, the snow and ice is finally over. Forecasted are highs in the 60s and lows from 40F tomorrow morning, and then warmer each morning after that. (45-50F)

At what overnight low temperature would it be safe for me to leave the tomato plants outside?

So far, they have never experienced temperature lower than 55F.

Worth1 · March 7, 2015

Anything above freezing, mine are planted right now in the garden.
If they dont freeze and die then it wont hurt them, I dont care what the experts say.
I also dont buy into the hardening off for cold weather either, you harden off for sunlight.

Worth

Blueaussi · March 7, 2015

I don't like to leave mine out until the nights are no lower than 50F. One or two nights in the upper 40's is ok, but if it's getting that cool at night, the soil will still be too cool anyway. I always take the soil temperature at the depth I plan to plant, and I want it to be at least 50F, too.

This is more important for peppers than tomatoes, but I would still rather hold off a week or so and let the soil warm up. Cold soil, especially if it's wet, is an invitation to disease. Containers warm up faster then the ground, but I would still check the soil temperatures and plan hardening off accordingly.

BriAnDaren · March 7, 2015

Last year, tomatoes did fine in our hoop house when temperature dropped to +2.4 C overnight.

Worth1 · March 7, 2015

Quote:

Originally Posted by Blueaussi

I don't like to leave mine out until the nights are no lower than 50F. One or two nights in the upper 40's is ok, but if it's getting that cool at night, the soil will still be too cool anyway. I always take the soil temperature at the depth I plan to plant, and I want it to be at least 50F, too.

This is more important for peppers than tomatoes, but I would still rather hold off a week or so and let the soil warm up. Cold soil, especially if it's wet, is an invitation to disease. Containers warm up faster then the ground, but I would still check the soil temperatures and plan hardening off accordingly.

I just checked my soil temp at about 4 inches depth next to a tomato plant and it is 55.5 F.
This is after several days of cold weather and rain.
Today the sun came out around 12 noon.
The temperature in the shade is 62 F and the radiant heat from the sun on the soil is 105.6 F.

Warm enough for me.

Worth

AlittleSalt · March 7, 2015

Our ground temp at 6" is 50F. I'm planting potatoes finally. They needed to be in the ground a week ago, but I wasn't interested in standing on ice to do it.

Worth1 · March 7, 2015

Quote:

Originally Posted by AlittleSalt

Our ground temp at 6" is 50F. I'm planting potatoes finally. They needed to be in the ground a week ago, but I wasn't interested in standing on ice to do it.

drew51 · March 7, 2015

I like to wait till it's above 50F at night. yes they can survive, but in my experience the cold seems to stunt them. I have had plants I kept in outgrow the ones outside in the cold. Sure they will not die, just be stunted, and set back. Now in places with long seasons, that may not mean anything, but here the season has limts, and shocking your plants is not helpful, and delays harvest, thus reducing yields.

March 7, 2015	#1
AlittleSalt BANNED FOR LIFE Join Date: May 2014 Posts: 13,333	Leaving Tomato Plants Out? The ideal time to plant out tomato plants for my area is supposed to be as early as Mid-March. Which got me to thinking about eventually leaving the plants outside at night while hardening them off. This week, the snow and ice is finally over. Forecasted are highs in the 60s and lows from 40F tomorrow morning, and then warmer each morning after that. (45-50F) At what overnight low temperature would it be safe for me to leave the tomato plants outside? So far, they have never experienced temperature lower than 55F.

March 7, 2015	#2
Worth1 Tomatovillian™ Join Date: Feb 2006 Location: Den of Drunken Fools Posts: 38,539	Anything above freezing, mine are planted right now in the garden. If they dont freeze and die then it wont hurt them, I dont care what the experts say. I also dont buy into the hardening off for cold weather either, you harden off for sunlight. Worth

March 7, 2015	#3
Blueaussi Tomatovillian™ Join Date: Apr 2009 Location: South Carolina Zone 8a Posts: 1,205	I don't like to leave mine out until the nights are no lower than 50F. One or two nights in the upper 40's is ok, but if it's getting that cool at night, the soil will still be too cool anyway. I always take the soil temperature at the depth I plan to plant, and I want it to be at least 50F, too. This is more important for peppers than tomatoes, but I would still rather hold off a week or so and let the soil warm up. Cold soil, especially if it's wet, is an invitation to disease. Containers warm up faster then the ground, but I would still check the soil temperatures and plan hardening off accordingly.

March 7, 2015	#4
BriAnDaren Tomatovillian™ Join Date: Jun 2012 Location: Ottawa, Canada Posts: 14	Last year, tomatoes did fine in our hoop house when temperature dropped to +2.4 C overnight.

March 7, 2015	#8
drew51 Tomatovillian™ Join Date: Dec 2013 Location: Sterling Heights, MI Zone 6a/5b Posts: 1,302	I like to wait till it's above 50F at night. yes they can survive, but in my experience the cold seems to stunt them. I have had plants I kept in outgrow the ones outside in the cold. Sure they will not die, just be stunted, and set back. Now in places with long seasons, that may not mean anything, but here the season has limts, and shocking your plants is not helpful, and delays harvest, thus reducing yields.