lowest tolerable temp outside for maters?

[rzr]

How low does the temperature outside need to be for about 8 nighttime hours if I have tomatoes outside in pots not planted yet for them to die or be damaged?

For example, one night this week it may get down in the upper 30's. But even if it gets in the mid 40's?

[bryanccfshr]

My plants have experienced a few nights out in the mid 40's with no negative displays of maltreatment.

40 degrees is when I bring mine in or cover them. If the seedlings are small enough a cloche(like a bucket or milk jug with the bottom cut out) should provide protection against the potential for frost tuesday night. Mine will just go under the cover of the back porch.

My major numbers for protection. If lows predicted at @40- it goes under a cover such as the back porch, 35 it comes inside the garage. You may also simply get some groweb type cloth that offers around 4° of extra protection. If they are in pots the easiest thing is to bring them to the protection. of some overhead coverage to prevent frost from settling out on them.

[grungy]

Our tunnel heaters are set to come on at 38F, and we haven't experienced any damage, at least not past the 2nd set of true leaf stage (which is when the babies move outside).
Hope this helps. My guess (and only a guess is the plants the furtherest from the heaters, might get down as low as 35F on the coolest nights.
Cheers,
Val

[nctomatoman]

I've had thousands of seedlings outside on nights where it has gotten to 34-35 degrees with no problems (if there is wind-blown rain, the plants survive but the foliage doesn't look so good!). I've also had seedlings covered with Reemay (frost cloth) to 30-31 degrees come through fine.

It is amazing what you find out when you can't possibly move 200 or so flats of plants inside (because there is no "inside" that will fit them!).

[TomatoDon]

Using a Wall of Water, MarkFeron started one plant under a snow drift a couple of years ago. He posted pictures here the first couple of months T'ville was on the air. The only problem, MarkFeron didn't last as long as the tomato.

From time to time we still debate the authencity of the MarkFeron tomato here at T'Ville and the whereabouts of both. It was an amazing event any way you consider it. In fact, legendary.

The infamous MarkFeron "Snowbank Blush" tomato thread:

http://www.tomatoville.com/showthread.php?t=295

Don

If you think it will get in the low 40's or below you should probably take precaution to safeguard your plants.

[jcmorse33]

Ditto the take precautions when temps are expected in the low 40's or below. Last year was my first one growing from seeds and I was a bit too enthusiastic on hardening off my seedlings. Lost almost half of my early batch to cold damage on a day in the 40's when we got some gusting breezes to speed up the cooling process.

[robin303]

Had all my tomato plants out in the garden for a few weeks now. I had them planted every 3’ among my broccoli and collard greens. Well it dipped to 35 one night and they were small and it was dark and really couldn’t find them. So I didn’t cover them up and I lost just two. So I think 35 is the limit without covering I guess and the rest are doing fine.

[cottonpicker]

I've had hardened-off tomato seedlings transplanted into open garden and they survived unexpected nitetime temperatures of 36-38 degrees with no loss of life.
LarryD

[JerryL]

While I realize this is not a direct answer to your question I thought it would be of some value. I have had plants in the ground be damaged by frost to the point that nothing above ground was alive. Just mushy brown stems. A week later small green shouts were coming up. Some of these plants were the heartiest I had that year.

[duajones]

We are expecting lows tonight in the upper 30's or low 40's. My plants are dealing with wind gust close to 40 mph today. I plan to cover them tonight just to be on the safe side. I just planted out on Sunday after a couple weeks of hardening off.

[CLa]

Dew point is a factor to consider. If you have a temperature of 36F and a dew point of 28, theoretically the temperature of the surface of the plant could reach 28. Like when you windshield frosts even when temperatures did not reach freezing. Covering them usually takes care of that though.
I like the 35 degree general rule, but I'm going to bring my plants in tonight just in case. Besides the forecast here calls for 33 at the moment.

[bryanccfshr]

My wife ran out at 3 am this morning in the blustery wind and drug the plants inside. I told her that tonight is the night we need to be concerned for.. after that I think we are looking pretty good.
I am lucky to have such a wife who will run out in her PJ's in the middle of the night to protect the tomato crop when I am not home.

[harleysilo]

wall-o-water thread is a disappointment to say the least....

[MichaelC]

The Temp here today in Sanford was 86, the low for tomorrow night is predicted to be 36. Now that's just crazy! I've already planted my Tomatoes, eggplant and peppers. The tomatoes have been in the ground since Jan-29. The peppers don't have cages yet and I can cover them with some sheets, but the tomatoes have 4' & 6' cages. They will be hard to cover. I have a 'few' backup plants in pots that I have moved under the cover of the front porch. The trays for cucumber, summer & winter squash, and watermellons have been moved back in the house till this blows over. (although I have already planted out some of my cucumbers)... We shall see... We shall see....

[BVGardener]

Where I live, I won't risk anything below a local weather forecast of 42 degrees. That is because the low temps in my area will consistenly drop about 8 degrees less than what the local forecast calls for.

Case in point - the forecast for last night's low was 31 degrees....it was 24 at my house. The transplants don't mind 50, 40 or mid to high 30 degree weather but the risk factor is just too high when it gets near 40 degrees and the potential for a northerly breeze or extra low dewpoint increases the chance for an unexpected freeze.

Jay