Hi Mona,

Mona, since summer's coming to and end, and days are growing shorter, you can probably get by w/o repotting or pruning till next spring.
Unless you find yourself watering daily, it could be put off till then..How often do you water?
What I've read and seen on tv ragarding root clipping, you're also supposed to prune 1/3 of the foliage..1/3rd of each actually, top and bottom.

Mona what type of pots are your citrus planted in? What material? I buy tree pots, (can find the addy for you) that come in different sizes, very light-weight and semi inexpensive..They're definatly not ornamenal pots, but do the job..Makes it easier lugging trees back and forth.
They're basically black pastic pots, tall in height..the largest, (sorry I don't have exact dimensions)is large enough to fit tall citrus.
These containers have good-sized drainage holes, so you don't have to worry about rotting, or root damage.

Why are you contemplating root rot? Do you suspect your citrus has this problem? Rot indications are mushy roots and trunks (trunks when plant is in really bad shape) also rot emits a sour odor. In other words soil starts smelling bad, it stinks..Literally.
If your tree is totally rootbound, there is little chance of this happening. Unless roots are constantly sitting in water, day in and day out.
Though I consider citrus a semi-dormant plant, as short days progress you'll see little growth..flowers and fruit is another thing. Citrus seem to bloom/fruit year round, then again it depends on the type. Meyers, Calamondin oranges and Kumquats seem to be ever-bearing. (at least via my experiences) Others, like Navels bloom/fruit at certin times of the yr, depending on heat and amount of sunlight.
BTW, did you fertilize this year? If your tree is given proper light, then feeding should be done, but once days shorent and temps cool, be careful using fertilizers..In autumn I spray Fish Emulsion as a last foliar feeding and a preventive against scale.
So, if it's just recently your citrus stopped putting on growth, that could be the reason..and since you're in zone 6, our plants have less time to grow than like those who live in Fl and Ca.
Of course, a totally rootbound plant hasn't room to grow, so this will also slow down growth..But it's up to you how you want to handle it. Good luck, Toni

Hi Hopeful--thanks for the note. This is a Ponderosa lemon tree and it is in a black plastic tree pot, and pushes flowers every spring, usually starting around late February to early April. I hand polinate with a small paint brush.

This year I had the most fruit pop, but only two stayed on the tree. I'm told that's normal, that most do fall off. The tree was pretty with a lot of flowers and new growth, and I did prune some of this off, but kept the tree in good shape.

I'm watering every couple of days, not every day. I moved it outside with some effort to get it soaked by the rain we've been having.

When we had really hot weather is when it started to look spindly and all the small new growth started to die back, and I wondered if lemon trees can get heat stroke indoors.

It has been in this pot for about 4 years without repotting. Like I said, it did get pretty bushy this spring, but now it's startingto look spindly.

I'm worried that I might not get the flowers and fruiting with the growth spurt in the spring as I usually do if it's root bound. The soil is very full of roots if I go down even one inch--I don't want to barrow trouble, believe me!

Is there a rule about how much room there should be around a root ball?

Thanks,

mona

The 1/3 rule is absolutely not true. As a matter of fact, there ARE no hardfast rules about root pruning, really.

Mona, if you are convinced that your plant has run out of room for the development of new roots in the container, then even a small root pruning can be of benefit. If the plant is in trouble because of the inability to generate new roots, then the process can be done at any time of the year but the fall is a perfectly good time! Do NOT prune the top at the same time. For your situation, I'd just take a little from the sides and the bottom. Do not take as much as 1/3 of the root system off, by the way.

Root rot will appear as blackened or slimy roots. Their might not even be much of a root system if the problem has progressed or has been chronic

Rhizo, I only mentioned to Mona what I saw on Victory Gardens..pruning top and roots was an option they recommended so as not to set in a larger container..I have never personally done this to any plant, let alone citrus, then again, I don't mess w/roots or prune citrus. Whenever roots fill a pot, I up the size..
I sure don't want anything happening to Mona's tree because of advice I've given her..But since cutting 1/3rd roots and top was shown on Victory Gardens, a reputable show, I didn't think any harm would come her way.

Rhizo, if you've had luck removing roots w/o cutting foliage, then it can be done. Like I stated, I've never experimented either method. (w/citrus)

Mona, I've read 2-4% fruit remain on a tree..which doesn't sound like much, but when you see citrus w/numerous fruit growing, it sure is impressive.

Watering every other day is a lot, but it depends on weather, (you said it was hot there) pot material, soil and humidity.. What type of soil did you use? Do you recall since it's been some time since you repotted. If well-draining, naturally soil will dry out faster, and if potbound, well, I can see why you have to water every other day.
I have a simiar dilemma..I've 3 citrus that really need repotting.,.bought them last fall, but never got around to repotting..soil is all roots. Everytime I plan on repotting, it rains or something comes up..LOL..That's life I guess..
My Murray's container is so old, every time it's lifted, plastic cracks, pieces break off..that one needs repotting, too. What a mess!!
Citrus can get sunburned, and I'd guess heat stroke if hot enough..It's been in the 100's here, too, so each night I go out and hose which cooled the area..
Is your citrus sitting in a direct sun, non-sheltered area? When days get really hot, perhaps you can set in a cooler location, if possible..
I don't know of any rules as far as how much room the rootball needs..Some ppl place trees in huge pots and are successful, but others kill their plants by overpotting..I normally plant up 2 sizes w/citrus. Because my soil is well-draining, I don't worry about overwatering..To those who have a tendency to overwater, I don't recommend potting in barrels like some ppl do. Or even those who live in cold climates where plants are slower-growing.
If you prune roots are you still planning on repotting or keeping in the same pot? Toni