In my opinion it looks like its either over fertilized or under/over watered. I am no expert but you can start with that information and think about what you have been doing. Has it gotten a lot of rain? What is your watering/fert. schedule?

-Doc Citrus

rfruit,

Since you state "I don't believe it's the watering, soil or nutrients alone as it changed so quickly after a year of being ok", I'm inclined to agree with you that the cause of your tree's pouting is most likely due to the change in environment. This is the only variable that's changed. To rule out watering (over or under as a result of change in it's surroundings), can you just tell us how you're monitoring for soil moisture level? Using the dowel method hopefully?

I would recommend NOT changing your currently fertilizing regimen - you neither added nor subtracted from your current feeding routine, so there's nothing to suggest that this is the problem.

Regarding your current discolored/unhappy leaves, there's nothing much to do about it now. These are the older leaves anyway and being outside in sun and warmer weather will result in a new flush of leaves/flowers in short order.

Tim

Thanks for the responses guys.

I mentioned I didn't think it was the water or fertilizing, but it certainly could be. Again, I'm a rookie and that was just my guess. Feel free to correct me - you all know much more than me so you're not going to hurt my feelings ;)

My soil moisture test is pretty basic - I stick my finger in the soil about an inch down and if it feels completely dry I water it. I dump enough to submerge the rootball before it all soaks in. With this method I end up watering it every 2-3 days. Not very scientific I know but it seemed to be sufficient. The pot has some gravel in the bottom so drainage is pretty good. When I moved it outside we did get a couple pretty rainy nights so it probably did get a bunch of water those 2-3 days. Perhaps that is also a factor. I had assumed 2 or 3 overwaterings wouldn't be that bad given that it has pretty good drainage. I'm going to google the 'dowel method' now. Thanks for the tip.

As for fertilizer I have to admit I only added it once at the end of the winter and it was some generic Miracle Grow plant fertilizer, nothing special for citrus trees. Go easy on me guys. I figured a generic fertilizer applied sparingly would either help or at worst no hurt too much. I'm going to order some citrus fertilizer soon.

If the leaves are just falling off to make way for new ones I should see some newer, tiny leaves coming in right? It must seem like I have no idea what I'm doing... which is probably true it large part. I read some stuff when I got the tree and followed some simple rules. For a year the tree did so well I was convinced key lime trees were so robust you didn't have to do much at all. Clearly I was wrong.

rfruit: Now that you mention your watering frequency and your method for determining moisture, I am a bit concerned. Can I also assume that your Key Lime is planted in regular potting soil? If so, this, coupled with your frequent watering could very well be causing your tree to decline.

Please do read (and re-read) the very dense link I've included below by Al who is a well respected and very knowledgeable source on container gardening. A lot of us who grow in containers use his 'Basic Soil mix' formula towards the end of the article.

Regarding the 'dowel method', it is simly the use of a pointed wooden skewer (like that used for BBQing). Merely stick all the way to the bottom of your pot and pull out; if it comes out moist at all, do NOT water. The use of your finger into the first 2-3 inches of soil is insufficient, since you are failing to determine how much water resides below that level where the majority of the roots reside. You could be slowly killing your tree with too much water (most certainly the case with the 'perched water table' problem Al mentions in the link by using regular potting soils AND watering every 2-3 days!).

For your fertilizer, do consider Dyna Gro's Foliage Pro. A lot of us here use it for our container grown citrus, since it has ALL of the major and minor nutrients your citrus needs.

Good luck, and keep us updated on your Key lime.

Tim

Here is a link that might be useful: Container Soils - Water Movement & Retention by Al/Tapla

No offense but it seems rookies always think they are not over watering their plants when in fact they are(Ill admit I was one). Im not saying this is the situation but from what I could see that soil looked pretty dark and moist.

I would agree with Dr. Citrus. Based on looks alone it looks as if its over watered. It also looks like the beginning of some kind of phytoxicity or lack of nutrients. Have you sprayed anything on your plants lately? If not I would suggest to cut back on watering and feed that baby!

During winter, especially indoors, citrus dont need frequent watering and from what Ive read they need to be slowly introduced back outdoors into the sun.

Just now circling back on this post. Thanks again for all the info to everyone who responded. Great information here and tremendously useful to a rookie like myself (I bookmarked the container post). I've started using the dowel method and after a couple weeks I can tell it was definitely being over-watered. The rain alone was doing that (we've had a very rainy May here in MN). I ordered some Dyna Gro's Foliage Pro and will use that moving forward.

The tree has started sprouting some new leaves so it's not dead and I think I can turn this around. I'll post an update later. Thanks again!