I don't know how much heat those lights generate; I have always used a light blanket with a lit 100 W incandescent bulb hung from a lower limb in the center of the tree. Funny thing, someone once asked me how putting in a 100W bulb would warm the tree; and I had to explain that you have to turn it on!!

If you use your plan, can you let us know how it works, and maybe what the temperature under the blanket is in the morning, compared to ambient temp. Luckily, where I have my Meyers, there is no frost ever; but I am sure many people here would like to know what you do (take a photo) and how it works.

As long as they're not LED lights, and the regular old incandescent lights (mini or otherwise), then they will generate a fair amount of heat. But, you do need to toss over some frost cloth, and make sure it is completely sealed on the ground securely with stones or bricks, so the warm air doesn't escape. If your trees are small enough, a small frame to support the cloth so that it doesn't touch the canopy is even better. If not, any leaves touching the frost cloth can get nipped. Frost cloth should be cheaper, and the key is getting the cloth to the ground completely. Otherwise, not worth the effort. If you're really afraid of freezing temps, I would also suggest your flood the trees with water, to help keep the ambient ground temp up. This is what commercial orchards do, now - wind and water.

Patty S.

Patty

Do you have any concerns in your orchard with the cold snap we are about to have?

I have a lot of trees planted this spring and the one before, but not sure if I want to cover a couple of them or not (my variegated pink lemon tree is kind of fussy and finally looking fairly good)

Yes, Kippy, a little concerned. Temp tonight (8:19 pm PT) is currently 41 degrees F on my weather station. So, it will dip very close to freezing tonight here, even though the general weather report for Vista, CA says we will see a low of 41. Hence why I have my own Davis weather station in my yard :-) Supposed to be a few degrees lower tomorrow night, even lower Saturday night. I'm hoping for significant rainfall on Saturday, which will help with soil temps. This is early for such cold temps. It makes me concerned for January. I have given up planting mangos and papayas here. I can't believe I'm saying that. I would not have said this maybe 5 years ago. But temps are consistently too cold in the winter over these last 5 years to consider either, now. I will probably cover tomorrow night. Possibly move a couple of my potted citrus into the garage over night. Ugh. This is so unusual for us here. Born and raised in California (Orange County - Huntington Beach) and cannot remember consistent winter weather like this.

Patty S.

Yikes! I didn't expect it to get this cold this early either. It's 9:30 pm and my thermometer says it's 29.5 F outside. I feel a little silly for planting 7 citrus trees just a couple weeks ago...They're covered now, but I'm not sure how I'm going to cover them when they're full grown dwarf trees...

Patty....
Must be that GD global warming! LOL

Stay warm.... I am going end of this month to Madrid and Copenhagen... way too cold for me; but it is a grandchildren thing.

I checked after the first night, a few of the trees have some new tender foliage that got damaged. And pretty sure the zucchini are now done for the season....lol

I think I need to work on a better system of cover cloths for our little orchard.

When I was a kid, one of my favorite sounds on a cold night was the whir of the orchard fans. The orchards are long gone that had them, but I did love the sound.

I HEARD THAT JOHN

Unfortunately we are going to be hit to. Temperatures are dropping low enough to kill all my fig trees to the ground. However I am prepared for this and I will be able to protect the lower 3 feet and since my hardy chicago figs fruit mainly on first year growth I'll do very well.

I HEARD THAT JOHN

Unfortunately we are going to be hit to. Temperatures are dropping low enough to kill all my fig trees to the ground. However I am prepared for this and I will be able to protect the lower 3 feet and since my hardy chicago figs fruit mainly on first year growth I'll do very well.

C7 Christmas lights make a big difference. Last year I used frost cloths alone, and my young avocado trees sustained severe frost damage. This year, I added the incandescent Xmas lights under the frost cloths, and the new trees are doing much better. It was 27 degrees last night, and colder tonight. Highly recommend the lights if you have an electrical outlet nearby.

For my Bearss lime nearby but without any lights, I plan to add a jug of hot water under the frost cloths.

For your bearss limes if you leave the tops off the water will steam and humidify the air as it goes up and it will condense on the frost cloth The condensation releases a treemendous amount of energy into the air on the citrus side of the cloth. As the condensate changes to ice it releases even more energy on the citrus side of the cloth. This faze change occurs at 100 % saturation of the air at 32F for water to ice. This forms a barrier that keeps the interior air at 32F on the liquid and you tree gets no damage. The frost on the cover is full of air pockets and increases the insulating values of that cover. Just make sure you use a number of them such as pots, pans, watering cans, coffee cans with water, and etc.

Best of luck
Steve

I picked up a Lisbon lemon tree last spring and stuck it In front of a brick wall in front of my house with south west exposure. I wrapped some old Christmas light around and have been running them at nights. I was planning on using a blanket on it but it didn't seem needed yet. This tree has yet to drop one leaf we've had up to minus six some nights. Last few days with wind chill has hit minus fifteen with no leaf drop and only minor frost damage on young new growth. Not sure what rootstock this things on but I can't believe it. I think it might make it all winter without any leaf drop. I didn't even think this variety is supposed to be cold hardy. Those lights help a lot.

Citrus tree do not feel wind chill. If it is -6 degrees outside with a wind chill of -15 degrees, then the wind is strong enough to pull heat out of a 37 deg object that still air would do at -15 degrees. This is what wind chill is based on. A citrus tree will fall to the temperature of the ambient air. So if a wind of -6 air has a wind chill of -15, the tree will remain at -6 degrees.

I am mentioning this so that now one leaves their tree out in -15 still air thinking that it is safe when just a week ago the tree took -6 degrees with a -15 wind chill. you tree will die if you do.

37 degrees was the choice temperature to measure from because wind chill is measured to protect HUMANS at 37 degrees ( 98.6 )

Citrus BC, no citrus, even citrus crossed with poncirus will survive -6 F weather. Even with lights wrapped around it and up against a brick wall. Citrus are semi-tropical plants. Lemons are on the low end of cold-tolerance of all the citrus cultivars (surpassed only by Mexican Lime). You might want to bring that tree inside and see if you can get it to survive after exposing it to catastrophically cold temps. And the additional wind will also add further damage to the leaves of a citrus tree, one issue citrus also have is not liking winds. So that, combined with sub-freezing temperatures = certain citrus demise :-(

Patty S.

Citrus BC --- Am I correct in assuming that the BC stands for British Columbia, and you run on the metec side of measurements of all kinds including centigrade. I didn't see a zone listed so I am assuming that the CA listed in your profile stands for Canada and not California. If so the -6C would translate to 21.2F and to have a wind chill -15C translates to 5F At these low of temperature we would need a 18-19 mile/hour wind. I have no idea what is considered windy for citrus. The tree will still remain at 21.2F and sustain wind damage of a 19 MPH wind. That leaves the tree lights totally useless unless the tree in in some kind of inclosure.

Steve

Even the slightest wind at those temps can dry out any plant left outside exposed to wind..

I can't even leave my trees near a window with a cold draft..That spells disaster too...

Mike