Just how cool/cold is it or will get , in degrees F?

We too are having a cold spell coming in PA after a beautiful warm week, So I decided to wait another week before planting mine, I personnely would cover them at night if it falls below 50 degrees.

Tomatoes are pretty tough fellas. Hard to tell without a pic. If they went in nice and deep and strong plants to begin with, they survive all sorts of weather shifting. If a bit weak and leggy they may like some cover.
I only get concerned if it dips down in the low 30's. Happened to me only once in 15yrs. The second week in June. (2004?). I have a half dozen water cooler jugs with the bottoms cut off.
And a hoop row cover system that can go up without much effort.

Since that tragic year i do sleep a bit better with a bit of cover.
Usually a personal call if you want to cover a few or a dozen. Since then, it has not made much difference in the few covered and the ones left alone. In zone 5a i just wait till the second week in june to plant...and use my cover jugs for newly planted tenders on occasion like basil.

-my main garden/farm is 2hrs north and only gets weekend visits. I don't have daily/evening/morning tending decisions to make. I just let nature/weather have its way... probably a good thing. : ) I may row cover, light white weave fabric, sunday afternoon if the weeks weather seems iffy.

If you do feel the need to cover with jugs, just remove early a.m. so they don't bake as the temps rise....but you probably know that.

We're supposed to get to 39F tonight. I did plant two toms a few days ago but I figure I have backups if they get zapped. I have the others in one of those little shelf greenhouses and I'm planning on zipping it up for the first time in quite awhile.

I agree with steevendog.

Whe I was in the process of hardening off, lows were mostly in low 40s. After plant out (on Apr. 4,5) quite few nights lows wen down to 38F and I did nothing interms of covering or other means to ptotect them. Even after almost 4 weeks past plant out we got lows down to 43F. Forecast shows that next week our lows will go down to 47F.

So If I had to be concerned with lows under 50F, I had to wait till mid June ( 2 1/2 months). There is a small chance that I will see some red fellows by then. Now my tomatoes are almost 20:" tall and most have buds or flowers.

Your Garden, your plants. Do as you like.

Thanks for the input. Crazy weather here again--it's been mid 50's and rainy and temps are not supposed to get warmer until Sunday or Monday! Forecast for temps to be mid 30's tonight. I think I'll play it safe and cover.

I think I'll play it safe and cover.

Wise move. :) It always pays to play it safe. Spring planting can be risky under even the best circumstances for many of us so always being prepared to protect the plants if needed has proven worthwhile for me many years.

This year we set record highs a week ago at 95+ degrees and now have record lows of 35 forecast for the next 2 nights. Even if it doesn't get down that low my plants will be covered.

Dave

I covered everything last night. I live in a valley and it gets cooler here than the forecast.

We are going through cold patch of nights again and it is cloudy and drizzling, which is rather good since it means there will not be frost. Still it is cold and my WOW plants are doing great, cept they are reaching tops of the WOW so might not offer as much protection if we get this crazy weather later on. I covered with plastic over tomato cages my other plants which are doing fine as well.
Hoping summer this year will start at some point LOL

Plants all looking ok and even have blooms. One more night to cover tonight and then it sounds like a warmup in sight. Sure hoping we have some dry days because soil is soggy from all the rain this past week!

I hear you! We had over 1" just on Friday - very squishy out there. Been hardening my plants off, but they haven't been outside all night yet - brought them in 10pm last night b/c it was supposed to get to 42, put them back out on north side of house (and moved when they were getting some afternoon sun at 4:30), then moved into garage bc tonight's low supposed to be 39. Maybe 1 more night in garage and then I'm going to start leaving them out once it's over 45. Start getting some sun too (just didn't want this afternoon b/c I had sprayed insecticidal soap in AM for fungicide).

I plant out very early in the spring in this very forgiving early season climate. Mid-February for tomatoes this year. Since that's a risky thing there are backup plants still in the warm and a stack of empty five gallon buckets outside for the iffy nights.

After two months of nursery work, three minutes flipping buckets on half a dozen nights to cover the plants get is very calming to the worry monster. In the morning they come off quickly once the sun hits them.

It's dead easy.

I haven't been able to leave mine out all night. Friday rained and was cold so I hauled them in. Last night went to 32 degrees, and it's going to be around 40 tonight. I don't think mine will be staying out all night for a few more days. ajsmama when are you planting out? I don't think it's happening here for at least another 7-10 days.

Well, mine went out a week ago so I was hoping for the 26th but considering they didn't see the sun all week (and were in the garage most of Thurs and all of Friday) I think it's going to be a few days later for the first batch. Still have some in the house, will move those out into garage as soon as the others are outside full time so it's going to be done in 2 phases - the tomatoes started March 29 will go in the ground about May 29, the tomatoes started April 6 and the peppers will go out about a week later.

Got the baseboards all together, reasonably square and level (some were warped) for the HT, will start making the beds as soon as it dries out a little (didn't walk inside the baseboards) so will be ready to plant. I've got to get the other beds prepped too (I don't know if DH amended them yesterday, still had 100ft to weed) and check the soil temp for the beans. The only things I've got in the garden so far are lettuce and kale transplants, seeded dill and more cilantro (though some cilantro came back), and that really hardy oregano. Oh, and I have some strawberries forming so I have to get hoops and netting up in the next couple of weeks too.

Wow, good luck! I've ordered pine bark fines which I'm going to mix with promix bx or hp. Not sure if I'll be having a raised bed or strictly container planting with smart pots. I really want to start leaving them out all night but for me, I still find the weather iffy. I have a few pots left in the house that I started late on a whim (April 22) that are almost 5-6" tall. I'm going to start hardening them off tomorrow. I guess putting them on a heated floor helped them to germinate quickly and they really took off, kelloggs breakfast. I'm actually shocked because last year nothing germinated from KB and this year I only got one that was worth transplanting. Then I decided to take a risk with plant out being later this year and so far so good!

Well, I've totally hijacked this thread now, sorry.

I don't know how cold it got last night, it was 48 at 1:30AM, but I didn't check when I got up at 6:30. Forecast says 44 tonight. Very blustery out now - been weeding, decided to come back to house to check plants (put out on north side 8AM when it was 52) to make sure they weren't getting broken stems/knocked off table. Seem fine. I think 1 more night in the garage and tomorrow set out for a little AM sun (will let them get some 4pm sun today).

April 22 seems late, my last ones were seeded April 6 (except for 1 Sophie's Choice and 3 Orange Minsk on the 17th, and they're only about 3" tall), I think I am on track for those to go out 1st week of June but I haven't started hardening them off yet. But maybe yours will be OK to put out mid-June?

Oh, also DD's science fair tomatoes started April 17 and 4 more last Monday - I thought they might take 7-10 days to germinate since the first ones did but 2 days on top of the fridge and they germinated in 5 days. Oops. Could try to start some today, leave on fridge until Thurs AM when she has to bring them to school, see if the little loops are poking up by then. They wanted to show some different stages in the lifecycle but of course I don't have any flowering/fruiting right now. Might find some at big box store?

OK, lunch break over, time to get back to work.

OK. Talking about tomatoes cold tolerance.

I personally have put them to test down to as low as 38F and they have not budged. But one thing to understand is that the nightly lows last for just couple of hours Maye 3 hours withing low to low +2 degrees.

I think most critical than air temperature is SOIL temperature. MOST plants do not mind cold air temps( few degrees above freezing). Florist keep their flowers in cooler happily for days. So I think tomatoes can thrive as long as soil temperatures are warm ( I would say 50F ++. The higher the better up to 75F).

The best way to verify this is to experiment and willing to loose a plant or two to gain knowledge.

When one understands that first, the damage done is not always visible and second, it is not always immediate but long-term, why risk plants unnecessarily when extensive research on the question has already been done.

Just few of the many sources of info that are available:

Influence of sub-optimal temperature on tomato growth and yield: a
review

Response of Tomato Plants to Stressful Temperatures

Cold Damage on Tomato Plants

Cold Weather Effects on Tomato Plants

From link below: Tomato (Lycopersicon esculentum Mill.) plants, which normally do not accumulate glycinebetaine (GB), are susceptible to chilling stress. Exposure to temperatures below 10 degrees C (50 degrees F) causes various injuries and greatly decreases fruit set in most cultivars.

Genetic engineering of glycinebetaine synthesis in tomato protects seeds, plants, and flowers from chilling damage.

Cold tolerance in Osmotin transgenic tomato

Dave

Edited to add my anecdotal info from my notes for whatever value it may have, if any. I have many times over the years misjudged my planting time and ended up with plants that were accidentally exposed to temps colder than 45. That temp is my personal low limit for forecast temps with unprotected plants because I have a good warm micro-climate pocket in some of the fields planted early. But it doesn't always go my way.

While some plants showed no obvious effects, in the majority of cases the plants performed below norms in overall health, growth patterns, and production as the season progressed. This when compared to the same variety plants that had not been exposed to the cold temps as they were covered. They had higher instances of BER and blossom drop which I credit to their compromised circulatory system and/or compromised hormonal levels. They also displayed more symptoms of nutrient deficiency and were slower to respond to nutrient supplements.

So based on my experience it isn't worth the risk to me.

This post was edited by digdirt on Sat, May 24, 14 at 13:02

Let me quott a paragraph from one of the above links:

"""""
Overview
Eager gardeners often start vegetable gardens as soon as the threat of frost is gone. Planting vegetables, especially tomatoes, in cooler weather doesn't mean that you will be harvesting before your neighbors. Instead, you may be exposing your plants to disease and growth problems that could be minimized by waiting. Daytime temperatures below 70 degrees F or evening temperatures consistently below 50 degrees F can damage or destroy tomato plants.
"""

If that were the case I should have stopped growing tomatoes all together.
After starting my hardening off on March 24 and subsequently planting out on April 4/5 (that is 50 days ago) this coming Wednesday our high will be 62F and low around 48F. And that is not the first time.

That is why I never trust article like that with bunch of subjective talking, without any back up controlled study data, side by side, systematically.

Some the articles are legitimate scientific study about OVERALL GREENHOUSE type growing conditions for optimum production and reducing energy costs (economics of growing) which has nothing to do with backyard gardening.

I am VERY SURE and aware MYSELF that tomatoes grow slowly in cooler weathers, EVEN ALL SUMMER LONG that is the case in our PNW weather, but to suggest that planting at the stated temperature condition ( less than 50F for lows and less than 70F for highs) "CAN DAMAGE AND DESTROY TOMATO PLANTS " is just plain none sense to me.

Lets just say that the guy who wrote those words in an expert to you, and you believe in him, but I am not buying his advice because I have experience and results that proves him wrong. My plants already are close to 30" tall and are setting fruits. And the temperature had been MOSTLY lower than what he is talking about all along.

If that were the case I should have stopped growing tomatoes all together.

Why do you assume it is an either/or situation? You keep insisting that for you the choice is either plant them out so early exposed to much colder than recommended weather or don't plant at all. That simply isn't true.

And then you go even further by repeatedly pontificating about it and recommending this approach to others when they ask. All because you are trying it with a few tomato plants in your location it is ok for them to do it too?

If it works for you fine - good luck. But why are you so insistent that others do it too?

Why do you insist on restating your claims about this over and over in so many threads? It is only marginally interesting, it applies only to you, and it is misleading to others. So why? Is it just to prove that all the research and all the experiences of so many others are wrong and only you truly understand how tomato plants tolerate cold weather? Now that would be arrogance.

Nothing in any research done or in any common practice says you cannot grow tomatoes when the outside ambient air temps are below 50 You simply (a) delay your planting when possible or (b) when it isn't you adjust the environment by providing cover so that the air around the plants is at least that warm.

There is a whole range of ways to accomplish it without any risk to the plants by simply growing them under some sort of cover. Lots of people do it. So could you. If you choose not to, that is your choice. But that choice in no way makes your methods correct or something to be advocated when it directly contradicts so much evidence.

You insisted on links. You got them. Many many more are available. So now you dispute their validity simply because they disagree with your claims. Then I and others can dispute your claims simply because there is so much scientific and anecdotal evidence against it.

The OP got their answer many emails/posts ago and so has anyone else who read this thread. There is no way you will be able to prove your claims about tomato cold tolerance are right and everyone else is wrong so it is way past time for you to let this issue go and move on.

Dave

This post was edited by digdirt on Sat, May 24, 14 at 18:49

I just made a direct quote from that article. And I disputed what it said.
"""
Overview
Eager gardeners often start vegetable gardens as soon as the threat of frost is gone. Planting vegetables, especially tomatoes, in cooler weather doesn't mean that you will be harvesting before your neighbors. Instead, you may be exposing your plants to disease and growth problems that could be minimized by waiting. Daytime temperatures below 70 degrees F or evening temperatures consistently below 50 degrees F can damage or destroy tomato plants.
"""""
And just pay attention to this statement:

""" F or evening temperatures consistently below 50 degrees F can damage or destroy tomato plants. """

Can damage and destroy tomato plan ???

The person who made such claim must be arrogant , talking without basis and proof, not me proving him dead wrong.

Dave wrote:

"The OP got their answer many emails/posts ago and so has anyone else who read this thread. There is no way you will be able to prove your claims about tomato cold tolerance are right and everyone else is wrong so it is way past time for you to let this issue go and move on. "

1- If op got his answers, then why did you make that long post with all those links ?

2- I did not make any claims without basis, trying to prove it. I just showed that the writer made an erroneous claim. My plant have been out there for almost 50 days and better than 80% of this time night temperature have been under 46F and day temps under 65F. And yet they are thriving and have started fruiting.

That is the end of story.

This post was edited by seysonn on Sat, May 24, 14 at 22:46

Living in South Jersey, I usually have my tomatoes in the ground by the end of April. If there is a frost, I mulch them with last year's leaves and I have never had a problem. However, this year I started several varieties with pellets and transfered them to clay pots after they had grown their second leaves. After a few days. I put them outside and noticed that a few had died. Their roots were not in the protected ground, they could not be mulched, and they were much younger than the ones I had previously planted. These 3 factors contributed to their demise. So my advise would be to wait til they're a month old before putting them outside. Hope this helps.

We have a somewhat different issue with planting time here in the Central Valley of CA. For us it can be a balancing act between planting too early and potentially harming the plants' future production due to occasional nighttime dips into the mid or high 40's F. or planting too late and chancing an early heat wave that can also cause flower drop because the nighttime temps may not drop to below 80 F for days on end.

I'm getting really antsy to get the plants in the ground and will probably do so next weekend if the 10 day forecast cooperates. I can always cover the tomatoes this time of year if necessary; not much I can do about the summer temps...