Hello,
I have 4 container citrus on my deck - 2 of them have fruits; a meyer lemon w/5 fruits and a bearss lime w/2 fruits. Here in Maryland we are expecting an early and temporary cold snap. Forecasts are for 44 degrees tonight. Do I need to bring the containers inside? Will temps of 44 degress hurt the fruit? Thanks!

I've always beed told that you are in danger of damage to the tree below below 41 degrees and also not to let the temperature get below 45 degrees depending on who you talk to.

Bears Lime are less tolerant of the cold as they are more 'tropical' and I have also been told that 46 is about the minimum for these over a period of time

Temperature often goes down by a couple of degrees less that the forecasters say and temperatures may vary if you live in a city (will be warmer than if outide a city) or the plants have been kept by a brick wall (again temperature will be warmer if they have by a degree or 2)

I'd be tempted to bring them in especially the lime and if these temps are going to continue, but not into a centrally heated room. A small amount of ventilation would be good as well as long as the room temp won't go below 46 degrees.

I don't bring in my potted citruses during the winter. It gets down to 24 deg F on the average winter and they can take it as the season's cooling down progresses gradually. Our record low is 12 deg F, and of course anything below 20 deg F, I'd promptly bring them into the garage with no lights, until the crisis has passed.

For those who want growth, as soon as the MAXIMUM air temperature falls below 50 deg F, bring them in. If the air MINIMUM temperature falls below 40 deg F, bring them in.

Joe:
When the tempt drops below the required min tempt for growth at night and when the tempt goes back up at let's say 70 degrees during day time does the plant resume growth?
I also do not put my citrus inside the house in winter but it appears that my citrus continue growing and put out new buds although at night the tempt dips down below minimum.

It's a tough call. I would think it's not so great for them to go in and out repeatedly either. And since the outdoor temps are gradual as opposed to the trees being plopped into 72ish house temps.........I don't know.

What about covering them/placing a large plastic trash bag over them for the night? Would that work?

Actually, it is getting the time of year that your containerized trees will not produce much growth or any growth at all setting outside. When the temperature of the "soil" in the container falls below 55.4F (13C) the tree will no longer grow. This holds true for the roots and the foliage. You might as well bring the tree in and keep it it for the winter, unless you know that your area will receive warm weather (60F or higher) for the next week or longer. It is much better on the tree to bring it indoors a little earlier, than later, before the soil becomes to cold.- Millet

If frost isn't in the forcast you shouldn't have to cover them at all. You can use a frost cloth or plastic to cover them when a frost comes, but make sure if you use plastic that it doesn't touch the leaves.

Thanks, as always, to all of you who took time to answer my question. I have a "citrus notebook" on my computer that I paste all these answers in so I have them to refer to. Stephanie

Millet, on the temperature of the soil in the container.

I've been getting night temperatures of between 46F (8C) and 54F (12C), but this is the lowest point and might not be at that level for more than an hour or two. I've also had a few nights at 60F. Day temps have reached 73 - 75 and we are forecast 80F today (unusual for this time of year in the UK!?)

My washington navel, verna lemon and bears Lime have new growth at the moment and are still going. The bears Lime especially as it has a lot of new blossom.

Does the soil temperature have be constantly below a certain temp to stop growth or are mine still growing due to the variety of temperatures they are getting.

Thanks, Nick

Hi Nick, when the outdooor temperature momentarily drops below 55.4F (13C) the soil in the container could still be at a higher temperature. However, if the soil is at or below 55.4F the tree will not grow, untill the soil once again raises to a higher temperature. When the soil again rises to temperatures above 55.4F growth once again begins. The rate of growth depends on how much above 55.4F the temperature gets. -During the winter I keep all of my greenhouse container trees at 64F (17.7C). Milet

Hi Millet, what temp do you keep your greenhouse to keep soil temps at 64*? Seems like it's gotta be over 70* My sunroom will be lows of upper 40's & highs of 60's this winter, so I guess I can't count on any growth. What about fruits that are ripening? Will they still ripen at those temps?

Patty, I keep the night time temperatures at 60F and the day time temperatures are various depending on the weaher. Most all of my trees are setting on 20-ft. plastic waterproof heating strips, that are set to 64F. To tell you the truth, I really don't know about citrus fruit maturing at lower temperatures, but I would think it should not be a problem. Actually, citrus fruits mature, rather than ripen. - Millet

Thanks Millet

I am so glad I live in Southern California, as I am way too lazy to bring in 20 containers. I'll just have to deal with the traffic, drive by shootings, Super high divorce rates, earthquakes and exhorbitant real estate prices.

I have new growth on almost every tree right now. Limes, Yuzu and Clementines are going crazy...

Everytime I come looking for an answer, all I need do is browse just a little to find someone has already provided the advice I need already. I'm having night cold snaps into the 40's now and my answer is right here. Thanks!

I really love this forum. You guys are just great.