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OK...cold is bad...but how cold is too cold?

Posted by bcfromfl z8a NW FL (My Page) on
Sun, Apr 5, 09 at 15:52

Lots of us folks in the South are getting "caught with our pants down" this week. I've had my plants out for three weeks, and am not sure what Monday and Tuesday are going to bring this week. (One can only hope that it won't be TOO bad.)

Since my plants are in tubs, that complicates protecting them, and if the wind is blowing as predicted, covering probably is only going to provide little to no benefit anyway. As long as temps don't go below 32F, is that OK? Or, are mid-30 temps enough to stall growth and cause plants to sulk for a while?

I've never dealt with exceptionally cold temps with tomatoes before, as I've always set them out much later, in May. I'm looking forward to hearing from you more experienced growers who know what cooler nighttime temps can do to tomatoes, and at what point those temps become a problem.

Thanks so much!

-Bruce


Follow-Up Postings:

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RE: OK...cold is bad...but how cold is too cold?

32 and they are dead. 40's are ok but even mid to upper 30's with wind chill can kill or at least severely damage them if not protected.

Plants in tubs can still be protected - just drape a blanket over the cage or stake. Just no plastic in direct contact with the plant itself.

Dave


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RE: OK...cold is bad...but how cold is too cold?

I cover my tomatoes with cotton sheets, several light layers and have kept them down to 26. Whatever you do, don't cover them with plastic touching the leaves. Also, don't touch the plant or covering the next morning until the temps have risen to at least 40. Good luck, I'm in Indiana and we have cold til May. My suggestion is to stock up at garage sales on old sheets, they work as row covers. I would bungee the covers near the bottom of your pots to hold the covers on, in case of wind.


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RE: OK...cold is bad...but how cold is too cold?

  • Posted by jean001 z8aPortland, OR (My Page) on
    Sun, Apr 5, 09 at 17:31

Wind chill doesn't affect plants. But temps below 50F will damage, stunt, or slow tomatoes.

Protect what you can and hope for the best.


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RE: OK...cold is bad...but how cold is too cold?

I am sweating too. Low of 31 Tuesday night. I have been saving 5 gallon buckets, old kitty litter buckets, and dumped out a big pot into a box to use for covers. My tomatoes have also been out since around March 7th. Would a cardboard box hold up to the cold. I still need a couple more items before Tuesday.


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RE: OK...cold is bad...but how cold is too cold?

Anything below 45 and my seedlings stay inside. Only the Garlic Chives (which seem to love the cold) and my flowers stay out in cold temps. We have 2 frosts Tonight & Monday night coming here in Middle TN. Cover yours well or bring inside. Peace - Steve


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RE: OK...cold is bad...but how cold is too cold?

>32 and they are dead.
not 100% true, but 99% effectively true.
My green house like thing got down to 32 for an hour, maybe two.
40 out of 120 odd are now well back on the rebound, 40!!! days later. 10 died out right, 20 died later on, up to 40 days later on. another 50 are still barely scratching to be alive.

In another 10-20 days they be back to where they were when they froze.

It seems the bigger the plant, the better it will survive the cold.

Warning: it can frost in temperatures above 32, especially in low areas.
If frosted on, leaves are going to all die.
Hidden suckers will replace the lost leaves.

build a quick and dirty hoop house, and run a 100 watt light out to it.

ound 2' rebar into ground at 3' spacing, in a rown on each side
take 12'(or waht ever is approriate 1/2" pvc pipe and place over ends of rebar
throw plastic over the top
throw another layer of loose blue tarp over that.

Double layers works pretty dang well for my green house like thing. 10 degrees or so.


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RE: OK...cold is bad...but how cold is too cold?

I was wondering if anyone has ever tried using handwarmers beneath coverings? You can get them at Walmart for like a dollar and they last for 10-12 hours and put out some serious heat. Maybe cover the toms and throw a hand warmer in with it and make sure the edges are weighted down somehow? A few degrees would make all the difference, right?


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RE: OK...cold is bad...but how cold is too cold?

The key is to trap the heat in the ground, under the box/blanket whatever. The ground is warm and radiates heat upwards. If you can trap that, you are OK for a night or so.


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RE: OK...cold is bad...but how cold is too cold?

I lost 70 hairloom toms, peppers and flowers last night in a portable greenhouse to an unexpected 28 deg.

Ed


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RE: OK...cold is bad...but how cold is too cold?

I think I may have some good news for everybody. I'm currently testing a product that cold-proofs plants to 27 degrees F. Others have tested it with good results and now it's my turn. I won't say what it is until I can pass along the information based on my own findings, but if it works, it'll be a boon for commercial as well as backyard growers.

Even if it protects from freezing, the fact that the weather is cold means growth of almost any plant will slow, tomatoes for sure.

Some plants, like strawberries, need a certain number of "chill hours" a year to produce fruit. Tomatoes, unfortunately, are not on that list and actually need both lots of heat as well as a minimum of 10 degrees temperature difference between photo periods to produce fruit.

As soon as my research is completed, I'll post the findings here as well as on my Web site.


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RE: OK...cold is bad...but how cold is too cold?

I am glad to see I am not the only person who is fighting this blasted cold. I have 130 tomato plants out in my hoop buildings. They are under double layers of row cover. They made it through the last cold snap. It was suppose to be down to 28, that morning it was 23 degrees. They were all fine.

This weekend we had 73 on Saturday and 37 for Sunday. The wind blew 30-45 mph the whole weekend and is still blowing. Sunday night it was 27 degrees and winds in the mid 20 mph. I quickly looked this morning and they weren't blackened or limp. However, tonight will probably do them in.

Wind still blowing and the forecasted temperature is suppose to be between 18-22 degrees. I may loose this battle, but I will win the war. I have more plants to replace them. They are just the ones I was going to sell. They are a little later, but that is better than nothing.


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RE: OK...cold is bad...but how cold is too cold?

Thanks everyone for your thoughts and recommendations! I've been thinking about what I can do, and I'll at least try to cover the tubs as best I can. I'll have to rig up a bunch of PVC stakes to hold the cloths over the plants -- I'll have to take out the wire supports because they're too tall and will make too much airspace. Hopefully there'll be enough warmth in the tubs to radiate upwards and keep a small airspace warm.

Bricks, clamps, clothespins...are all in my arsenal for this afternoon! Hopefully it won't get cold enough to endanger my budding fruit trees!

-Bruce


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RE: OK...cold is bad...but how cold is too cold?

One thing about cold weather and plants freezing - 32 and below does not always kill plants. Growing up we raised tobacco. Seeds are group sown in beds that are covered with a cotton canvas. We always sowed the beds in early March and plants were up by April.

I counted 17 days of record low temps in April in the years I was around (1960-90), with some of the lows in the mid to low 20s.

We never lost tobacco or tomato seedlings. Whether it was because the plants are extremely dense, the canvas helped protect them, something else or a combination, I'm not sure. But it worked.

Mike


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RE: OK...cold is bad...but how cold is too cold?

I'm having the same problem. What about spraying the tomatoes with a fine mist. I can't cover mine, but I've read that the fruit growers in Florida spray to save their crops from frost. Will this work for tomato?


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RE: OK...cold is bad...but how cold is too cold?

No one mentioned wall-o-water yet. Do they not work or something ?

If anything they provide physical barrier against the wind and they are definitely a few degrees warmer in there. However, I believe the water deflect the Sun's Ray.

I am thinking about getting some big delivered alhambra water bottle, but the bottle out and put it over the plants.

Let us know how your children turn out.


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RE: OK...cold is bad...but how cold is too cold?

I'm going to try some rubbermaid totes with dirt piled around the sides. Hopefully I can keep the clothes hidden that I dumped out before the wife sees it and commits me.


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RE: OK...cold is bad...but how cold is too cold?

You can use sprinklers to protect from frost, but you can't shut them down until there are temperatures above freezing. We use them during the cranberry growing season to protect the tender flower buds and fruit once it develops. I get frost in my home garden until late May. I use the sprinklers late in the year to protect my tomatoes when there is frost. As I said, the only problem is you can't shut them down.
JMO,
Tom


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RE: OK...cold is bad...but how cold is too cold?

Johnny, the wall-o-waters work very well for frost protection, even hard freezes down to around 20 degrees. You can fold them into the tee-pee shape at night, or if your plants are too big, leave them opened up and drape a wet towel over the top.

I've had my toms in the ground since early Feb, unfortunately the plants were growing out the top so I had already removed the WOWs. Looks like I only got minor damage to a couple of the plants under a pcv frame w/tarps though.


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RE: OK...cold is bad...but how cold is too cold?

Lol every year I see how long tomatoes can survive on their own at the end of the season. Last year Champion Hybrids lasted through 13 freezes, and over 40 frosts and still did not die. I wouldnt produce any more tomatoes but it made it to thanksgiving in Annapolis!!

Good luck i dont think you have any problems getting the job done -


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RE: OK...cold is bad...but how cold is too cold?

Well, we dodged the bullet and the temps didn't get as low as predicted. Monday night the high winds kept the surface air warmer, and we only had a low of 40F. Last night, the weatherman explained that a high pressure feature moved into the Gulf, and helped moderate things...so we only hit 35F.

I took the frost cloth normally reserved for my grafted gardenia (and said a prayer under my breath, "You're on your own, buddy!"), rigged up a frame out of PVC, took the string of Christmas lights off my Satsuma tangerine, and found a long outdoor extension cord. I also had to rig up a wind break with plastic dropcloths, to keep the winds from lifting and carrying away the blanket.

Just pulled the cover off (since it's white, I can leave on during the day...yesterday just left it in place), and the plants look none the worse -- even a couple new blooms!

Thanks again all for your help and suggestions. Hope the rest of you fared as well!

-Bruce


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RE: OK...cold is bad...but how cold is too cold?

I planted 6 toms in early March and got them through one cold snap however this last cold snap was a doozie. I covered them up with heavy black plastic the night it got into the upper 20's and removed the covers when the temps got into the 40's. These plants were very healthy plants at about 18 in. tall. Some of them were very damaged in the cold and I snipped off the damaged parts. Question is- will they come back? I have a Champion (some damage), Better Boy (some damage), Brandywine (almost no damage), Cherokee Purple (heavy damage), Beefsteak (heavy damage) and a Roma (heavy damage). I am trying to figure out if I should replace the more heavily damaged plants. The Others had some new shoots that are still healthy so I am tempted to let those try and make it. How will this affect the overall health and productivity of the plant? And lastly - where on earth do I find a Cherokee Purple in North Tx? I bought it in Houston and brought it home with me.


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