I believe that citrus has very little root activity below 56*. No over watering, very light fertilizing,F/P, 1/4 ts / gl might be enough. Duration in winter feeding in Phoenix is short.

container temps with a lot of sun exposure keep soil temps higher.

1/4 strentgh at every watering my friend. That is what I would do. And you are good with wood working right?

I would make a cold frame sealed with plastic you could slip right over each tree or one big enough to fit all under on your colder nights. You coiuld even put a mini space heater in there to keep them warm at night just until it warms again. Boy, would I have fun leaving them outside all year long there.

Mines stay out even on frosty nights covered with tarp and a snall space heater inside until it warms up. I can get away with that until at least November)

Thanks Bob and Mike!
I'll think of a possible design for a cold shelter. It will have to be collapsible in order to stow away out of sight during the day. Since these are on the front porch, I have to be mindful of the aesthetic.

If your plants regularly put on new growth over the winter, and you are not worried about frosts, I would think a little bit of fert might not hurt.

But if they do dormant -- or if you WANT them to slow down, I would not fertilize.

Instead of a space heater you might consider those old time fat Christmas tree lights. I've used them for tomatoes and it worked well. Naturally, I can't remember how many degrees they added. Sorry. :-( I covered with frost cloth which you can purchase in bulk at Arizona Bag Co.

Arizona Bag Company

I don't think Travis has much to worry about from the cold in PHX. All he would have to do is slip them inside one or twice during an unusual cold snap.

Love these options! The Christmas lights could bring a bit of festivity to my front porch.

Travis!! Silica said exactly what I would do. I forgot your trees are in pots. Ha. Just bring them inside on those dangerous nights which happens very little. That’s what I do for a couple of mine like last night. The real big ones I cover. The smaller ones I just bring them inside. Like you said it’s cold only a short while. I’ll bet by the time you leave for work or the sun comes up it’s already warm enough out. Lucky you ))

How cold is too cold for a Meyer and a Ruby Red?

Sorry, yes, RR is grapefruit.

All I could find on the ruby red is this: TOLERANCES: Low frost tolerance. Prefers full sun position in a mild climate. Prefers slightly acidic soil with good drainage and no root competition. Moderate wind tolerance - and: Climate: Red grapefruit grow well in most parts of Australia, except for the mountain areas. They are frost tolerant, but the fruit develops best in warmer climates.

As always Travis, good luck with it all. Mary

Travis, all of mine, even my Lemon Meyer and Red Ruby stay outside as long as I can without freezing them to death, They do just fine. Take it from this northerner here. At times they will slow down, turn a bit yellow until it warms up, but never die unless you have them sitting in a very poor mix.

P.s And my days and nights stay a whole lot colder than your ever will. I can sit in the high thirties for hours before the sun even bothers to warm us up. Let's say from 3 a.m. till about 9 a.m. then cold all day after that. You are lucky to only have a quick cold night here and there.

Chat soon)