No one can tell you how often to water your plant by looking at some fallen leaves and fruit. I'm not at all surprised that you received two different answers. And we can't be good plant detectives, either, I'm afraid.

Truly, only by letting your own hands judge the moisture level of the container medium, will you know if your plant is under- or over-watered. It would not be at all unusual for a container plant to require daily watering, in that kind of heat. But even that depends upon many factors.

We don't know the size of your plant compared to the container. That can be important if you used a regular, bagged container medium. Not so much if you made your own mix out of ingredients that insure rapid drainage and super porosity.

The heat wave you've been experiencing can be very damaging to a container plant, too. Root systems can be steamed if not protected.

By the way, you should always drench the heck out of your plant when it is time to water. No little sips, ever.

Has this plant been in the same container for quite a while?

What kind of soil or soiless medium is it sitting in?

Does the soil seem compacted or loosened? In your heat, your soil should be drying out faster than 3 days if the soil drains well...;:-)

Have you checked the root system to see how the roots look?

If it is not root rot, then it sounds like your roots are getting way to hot to properly function from the heat.

If not root rot, can you shade the pots with something?

If the roots are bad, then it is a sure bet your plant is not absorbing a drink of water even when watered, all of course dependent on what the consistancy of your medium is will determine root vitality.

I hope you figure it out.

If your plants is rooted in a fast draining well airated soiless mix, you should be able to water everyday, especially in your kind of heat without ever a worry of root problems.
I hope you figure it out soon..keep us updated.
Goodluck,
Mike

Thanks, Mike and rhizo, for your replies. The tree has a trunk diameter of about an inch and is about 4 ft tall. It has been in the container its in now since I first got it last spring and I repotted it in commercially available citrus potting mix-- maybe Miracle Grow-- I can't really remember the brand. It may not be draining as well as it should as I have it on a stand with wheels that might be blocking the drainage hole. (I will try to get it off-- quite heavy-- and check it). I tend to think I am probably erring on the side of it being too wet. If I dig my finger into the soil to the joint it feels sandy and quite dry -- somewhat compacted due to roots--but I have moisture meter that says it is still wet farther down in the pot (this was yesterday about a day after watering). However, the heat wave has probably added to its stress. The strange thing is how the lemons were growing but then stopped abruptly and started falling off a couple weeks later.

Lauren,

I apologize in advance for my lengthy verbose posts. I may be able to help you since I have several container trees from Costco also and over 30 citrus in containers at the moment. Dealing with the heat in central CA has been an issue but I've learned a great deal by reading posts here.

Question 1: Is this Costco tree from Willits & Newcomb (would say on the original hanging tag if you have it). If so, the original soil would've been VERY heavy and looked like hard sand. It wouldn't have looked at all like the Miracle Grow Citrus soil you purchased for your 30" container.

I wrote a lengthy post to help you troubleshoot, and give you CA-specific advice for your tree, but I stripped it all out (I have it saved still) because I'd like you to check one thing before everything else.

Very gently check your moisture levels in several spots of the container. Esp. in the center vs. the outer edge. Is it VERY different in some locations (like a 2 in some spots and a 9 in other spots). Is the center soil difficult to push through and the outer edge is much softer?

If so, stop here and do not continue below.

Measure the original soil moisture level
Very gently remove some soil from one edge of the container. You probably don't have any roots near the edge yet, since it's a young tree in a huge pot. Keep removing soil downward to create a small tunnel the width of your hand. But definitely stop digging if you see any small hairlike white roots or if this appears to be stressing the tree (like shaking the trunk, or compressing soil too hard, or it screams mercy). Once you get lets say 6" down, remove a little more (couple inches?) inward towards the center. You only want to remove as little as needed in order for your moisture meter to reach the center area.

Once you've removed it put your moisture meter at an ANGLE so you're measuring the ORIGINAL SOIL near the center (it doesn't have to be directly under the trunk, but you want to be sure it's measure original soil). Again be careful to not rip roots with the meter, but measure a couple spots.

How does it measure? Compared to measuring from the top?

How does the soil 'feel'? Does the original soil in the center feel VERY different than the outside soil you added? Perhaps hard or dry and difficult to push through?

Chris

Chris,

Thanks for the help. Yes, it was from Willits & Newcomb and yes the soil is softer on the edge (new stuff) and more compacted in the center. In the top 3 inches or so I get a reading of dry to moist. If I put the moisture level in all the way, I get a wet reading. However, if I dig down in there toward the depth of the meter, it really doesn't feel wet and saturated to the touch... more like moist sandy soil.

I appreciate your willingness to help me troubleshoot this.

Oh yes, and I checked the drainage hole and it is free but water does not usually run through this hole when I water.

Chris, I admire your diagnostic work. Great thinking and well expressed.

I'm glad to help; I've been-there done-that with these trees in our local area. And what I've learned from these forums is an outstanding amount of technical information not just anecdotal advice (albeit sometimes all you can provide) esp. from Just-a-Guy above and one other infamous fellow.

My Diagnosis
From the information provided, I'm fairly certain your tree is undergoing a *very slow* death due to the center/original soil retaining too much water. This isn't totally your fault and the fact it has survived over a year, and even fruited, in a 30" container shows you haven't been extreme in over-watering. However, your tree came with soil that is less than ideal for long-term container survival; in fact, the W&N instructional tag is noticeably lacking directions for containers, only describing in-ground planting. At least half of the soil should've been removed (by gently combing outward) when you potted it. There was no way for you to know this without diligent research.

This explains the minimal drain-out even if you water quite a bit. I guarantee if you water the edges they will drain fast but the original soil retains a lot more (although not nearly as bad as an over-peat mix). You may ask yourself "why would they use this soil?"; I've described it below (FYI or for additional substantiation).

The situation
The yellowing leaf drop is typical for over-watered stressed trees (but remember your case isn't typical like the nursery folks suspect with normal container soil). The fact it grew three fruit, stunted, then held on to them for many months dropping them in spring was your first sign something was wrong (although absent other indicators can appear normal for young trees). Many roots have already begun rotting due to wet-feet. Being mostly shaded in an overly large 30" container has contributed to the problem. Now that we're in 100 degree weather, it's going to really struggle as it tries to replace moisture and breathe.

Even so, I surmise you'd have nurtured a healthy tree if you had purchased it from another source that provided container-friendly soil by default.

Your Options
The hot arid weather makes it very dangerous to fix at this point (especially since Costco won't take it back like big-box stores do ;-) However, wait-and-see increases the statistical certainty leaves will continue dropping and although alive, it will be beyond hope by winter.

My advice: I would accept this fate and risk it by attempting a fix now -- remove all the fruit and change out at least half of the original soil. If you'd like instructions on this, I can provide them. This procedure may kill the tree, esp. if done improperly or if it's suffered more than I suspect. But if it survives it becomes healthy very quickly.

Alternatively, you can wait it out cooler weather and IF the tree (somehow) hasn't further declined, the same fix is much less stressful on the tree. Further, you can buy a smaller container (maybe a 15") to downsize until then. Assuming you remove all the "extra" soil around the roots (without disturbing them), you will increase the odds of surviving until cooler temps. If it's a wooden slat container, it helps dry the soil and breathe better (but even plastic containers help). However, then you'd have to be mindful of rising soil temperatures in this heat; but your shaded patio may be adequate. Remember, this is opposing advice I'd give someone with a fast-draining soil mix. Asking a retail nursery to corroborate this advice would likely be futile.

Sorry for the bad news but here's hoping for the best.

Cheers,
Chris

THE REST IS *NOT* REQUIRED READING...

My Original Thoughts
it really doesn't feel wet and saturated to the touch... more like moist sandy soil.

I was hoping you'd find dry spots with your moisture meter - because in this soil, that would be a more "extreme" situation I would recommend you fix ASAP, even using a risky procedure. Dry spots in a container soil happen frequently under specific (non-ideal) circumstances. When patches of soil dry out, it tends to stay dry (hydrophobic) even if submerged in water. This can happen in several spots through out the container. I've seen it in ALL my container trees that either a) have two different soil textures, or b) are heavily root bound, or c) have worms in the container. I'll tell my kids "watch this" and dump an entire gallon of water on top of soil thereby flooding it, then peek under the soil 1" and it's as dry as a bone. It's a great lesson in how critical properly draining soil is.

The W&N Soil
The Willits & Newcomb (W&N) tree soil is VERY different than all the other nursery trees I've ever seen. W&N has provided excellent service responding to my email queries (from a home orchardist no-less). Their rep describes
"Our trees are field grown and then transferred into containers. The field soil is a sandy loam and then we add a pretty generic soil mix to fill the pot."

It has a high sand content but obviously has perlite with some peat but little to no woody material. I've noticed when it dries, the soil becomes almost rock-hard and doesn't absorb water well. But after absorbing it, it softens up nicely and then can absorb even more water. The rock-hard behavior at top soil may be caused by minerals from our local water. I was completely shocked at how much water I could throw at it until it finally drained (having been taught to always water citrus containers until 15% drains out). I could barely lift the 5 gallon container after this.

All my Costco trees are from W&N in this soil. All other trees I've purchased from CA nurseries use a fast draining mix that is more like the green and pink bag MG citrus soil.

IMHO, the W&N soil is a poor soil for containers long-term. However, it's a perfect soil for growers to use seasonally when trees are retailed indoors and in a non-nursery environment (ie. sold right next to clothes and furniture). It retains a moderate amount of water a very long time and is very heavy so they don't tip easily. It drains well once saturated, then holds the rest (doesn't "leak") but does have tiny gaps to store small amounts of oxygen for the root area. This is ideal for cold, moderately lit Costco, since the tree will grow slowly and need use little water and oxygen while seasonally on display. They need little care and few trees will die from inadequate watering like outside at nursery's in 110 weather or at Walmart. However, by end-season most are yellowing and are stressed -- but alive. The soil also performs well in very hot and arid Fresno when stored in the original black container -- much better than the other trees in fast-draining soil where the root temperatures will sky-rocket and bake. Again, this is all great for the short-term and OK for the medium-term.

To answer your original question: "to water or not to water".

You're pretty much damned if you do, damned if you don't. That's partly why you got two different answers about it.

In that soil if you wait until the "proper" time to water, your tree will suffer -- I'm assuming without enough oxygen, but I'm not sure. The tree needs oxygen into the roots which it mostly gets as watering pushes out the bad carbon dioxide. During normal growth outdoors, this specific soil needs this more frequently than it does the water itself. Again I'm not sure why but I've definitely experienced this.

Having learned to read the signs of the tree, I know exactly when to water my trees (in normal soil). However, after purchasing the W&N trees I was thrown for a loop.

I had 6 W&N citrus next to 3 other citrus, all in the original containers, recently purchased, with UV shades around the container. They were in a line along a wall, receiving the same amount of direct sunlight in 90 deg weather: morning plus a couple hours afternoon then shaded by my house overhang.

The 3 "typical" soil trees required water every other day, but everyday didn't hurt them. I patiently waited for the W&N trees to tell me when to water. After 7 days passed, I watered anyway. The next time around, after 10 days they started showing the signs -- but using the moisture meter showed they should've been fine.

This happened regularly and still does since I haven't repotted all of them yet.

Chris

Chris,

Thank you so much for explaining this problem and your experiences in such great detail. It is obvious you have a lot of experience and I feel confident in your assessment of my trees problem so would like to take your advice about repotting as soon as possible.

I'm sure I have a smaller plastic nursery pot around here I can put it in (perhaps even the original). I take it the roots are pretty sensitive. I'd love the your instructions on repotting, if you don't mind.

I think this info. you are giving is great and will benefit a lot of folks -- especially those who have bought or buy the Costco trees.

Thanks again,
Lauren

You're very welcome. I've spent many hundreds of hours reading over the last few months, especially on this website. I'm not an expert at all, but do know how to take what I've learned from others and apply it to my experiences -- I like to take risks with my own trees just to learn from the experience.

I'm certain Citrus roots are not sensitive compared to what I've read on this site, but I have little experience with non-citrus (couple dozen other trees/plants). Roots in general are not as sensitive as people think, but in your case I wouldn't want you to tear any "good ones" that are needed right now. Please also do not use the original container it came with. We're hoping the roots have expanded into the MG citrus soil over the past year.

At this point, I'm not sure I can give you the *best* advice you need right now. I know what I'd suggest and do with my own trees, but I'm wondering if you should start a new thread in order to get fresh input from others with expertise. When someone posts overly long responses like I have, the experts will move on to new threads (to help where they can).

I was thinking something along these lines, but feel free to post your own thoughts:

I purchased a young lemon tree over a year ago and potted-up into a 30" container, adding MG citrus mix. Apparently the original pot came with atypical soil, intended for in-ground planting and doesn't drain fast enough for containers. The tree is still alive but is now showing signs of stress, with all fruit dropping and leaves yellowing and then dropping.

Assuming the tree is in decline and will not survive if I do nothing, should I replace the poor soil now in my 100 degree weather (zone 9) or wait until cooler temps? If so, should I replace only some of the original soil or completely bare root it? What about root pruning if I find mushy/dead roots?

I would post this in the Container forum and maybe you'll get some responses. I'll follow along and we can continue on this thread, or off-forum, afterward. Also I'd really like to see a picture of the tree to verify my thoughts, if that's possible.

Thanks again, Chris. I posted as suggested to the containers forum.

Here are some pictures (hope I can this right).

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You can see the brown lemon and dropped leaves. The largest lemon is still there and I noticed I have two new baby lemons.

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the yellowing leaves

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a view of the fruit and a dead branch.

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leaf curling

"I'm glad to help; I've been-there done-that with these trees in our local area. And what I've learned from these forums is an outstanding amount of technical information not just anecdotal advice (albeit sometimes all you can provide) esp. from Just-a-Guy above and one other infamous fellow".

As well as I have learned a thing from you also...Thanks for all this info....;-)

Your explanation and well writen advice will definately keep me on my toes even more, to be an even more successful cont. citrus grower even up here in the East...
It is good to have people like you here..

The tree doesn't look that bad yet. Remember leaves yellow naturally and drop right before it's about to push out new growth. It is also normal for it to kill off a branch or two. However, from what we know about the soil, the lack of drainage even after watering, fruit history, and the combination of leaves dying bottom-up and yellow vein vs. green vein leaf yellowing -- this is the best move IMO.

Not a Full Bareroot
Unless we get some other advice about root pruning, at this point I'd suggest we remove the fruit and do only a moderate soil replacement (ie. about 50% of the original W&N soil). Besides a few bags of that MG citrus soil, you'll want a spade, spray bottle of water, a small cup to scoop out water, and a wooden chopstick or BBQ skewer (something long and smooth, with a tapered end, but no thicker than a pencil). This should be done as early or late as possible, in order to avoid direct sunlight and heat. You can do all this work without moving the plant.

Remove the Extra Soil
Start by removing the outer MG soil ring you added previously (up until you see a few ends of roots sticking out). We're hoping the roots have expanded from the old W&N soil into the MG mix you added; if you see a lot, this is very good news the plant will respond well.After the outer ring of soil is removed from the pot, take your chopstick and gently start in one section at time -- starting at the top and working down. Gently comb it out -- scraping soil outward so it falls downward into the pot (it will stay loose in there until your removal downward reaches the fallen soil). It's harder to explain than it is to do. Just work downward by poking in the top small amount and wiggling a bit
to "feel" the soil and loosen it, then pulling outward gently. If you hit tangled roots, I tend to stop pulling and jiggle it more to loosen them up. If they are very tangled (unlikely in this situation) I would move on to the next section; sometimes they untangle when you've worked out the roots on both sides of it.

Every few minutes or sooner you must water mist to keep the exposed roots moist.

For the MG Citrus soil, the soil removal works best if the soil is more on dry side. It will fall apart easier and NOT clump together. You want to avoid clumping because a clump can be heavier than roots can handle, and as it falls it sometimes tears them off. However, once you've removed all the old MG soil and you reach the original W&N soil, you will probably have to change it up. This soil is hard when dry and heavy when wet, so it tends to clump in both cases. For this soil, you will most likely have to use the water pressure method.

I usually take a picture at this point.

Removing the old bad soil
First try using the same strategy as before to see if you're lucky. Assuming not, before starting the water method cleanup the loose soil on the bottom of the pot that was worked out. Then use a hose with a "shower" sprayer option on it (water comes out evenly and with lower pressure). This will become a watery mess -- so verify your drainage holes are not clogged.
The Goal
You are only removing about the outer 3" of the old W&N soil (which was originally 11" in diameter). You are hoping to remove the majority of soil in those 3", so the roots will be exposed and intact. It is NOT important to remove all the soil.

It tends to follow the 80/20 rule -- you can get 80% of it removed in 20% of the time. You'll spend the additional 80% of the time trying to get the last 20% out. You don't want to spend that extra time with roots exposed trying to untangle or remove every last piece of rock or woody material. Roots tend to grow into the pores on wood pieces and won't fall out easily.

Spray
I normally like to go bottom-up when I use a sprayer, but the less we move the tree the better. Use the sprayer just like the chopstick, working downward and outward to comb it out.

Important: you will likely need to support the soil with one hand, while you spray that section with the hose in your other hand. You want to be as gentle as possible, but be wary of the time as each minute roots are exposed hurts the tree's chance of recovery.As the water fills up in the pot, you'll need to scoop it out with the cup. If scooping is taking way too long, get some help and while supporting the rootball and tree, the other person can tip the pot to to drain. You may do well and not tear many roots off. But if they are already brown, mushy and "ill" they may fall off easily (which doesn't matter a whole lot, they were dead anyway).

Once you're done with the old soil, drain the pot of water, verify your tree is still centered, and start placing the fresh soil around the bottom. Gently wet the soil as you build up (not soak) but we don't want to put overly dry soil against the roots. We also want to settle the soil as we go, not settle ALL at the end.

Try to work the new soil inside, between, and around the exposed roots to support it as you build up. Haphazardly dumping soil around the sides to backfill will only cause them to be pulled downward and possibly tear once you water it.

I'd take a picture as your halfway up the side.

Cleanup
I would dispose of both old soils and replace with fresh MG citrus soil. Water it very thoroughly and you've done well if it doesn't settle A LOT lower after waiting a few minutes. If it does settle lower, you'll see the original soil protruding from the top higher than your new soil. Add more soil if needed on top. Also add fresh mulch. Remove the fruits. I also remove any leaves that are clearly about to fall off. That way I can keep track off how many fall off after this process is finished.

Praying for the Best
Move the tree back into a more shaded position on your patio, the indirect light and our heat should be plenty while the tree tries to rebuild roots. If all goes perfectly, you won't have any more leaves fall off (other than what were about to anyway -- this would the most positive outcome. More likely, you'll have a continued decline (more leaf loss) from the previous illness and new stress -- but it should bounce back in a few weeks.

Take a picture and monitor it everyday to check for pests, etc. You shouldn't need to water it again for probably over a week. But we'd need to see first.

Any questions? I crazily typed this up and don't have time to proofread until later tomorrow, so I thought I'd post it now for you to get a head start on reading/preparation.

Good luck!
Chris

Thanks, Chris. You are a gem!

Let me know how it goes.

Once you get it finished we'll want to make sure you don't over-water in the new soil and you may need to lower the Ph (a bit) when you do water and feed -- to assist with nutrient uptake. Both are just in case they were contributing to the previous yellowing leaf drop.