We successfully started a key lime tree from seed 6 years ago. This year for the first time we got blooms and so in the hopes of getting it to bare fruit we thought we should perhaps fertilize it. We used a Jobes citrus fertilizer Spike. 8-11-11. Within a few days leaves started going brown around the edges and as of yesterday entire groups of leaves are browning and falling off. We have removed the spike but is that enough? should we be changing the soil or giving it a good rinse or anything of that nature? We don't want to lose this tree it's been a real Labour of love. any help greatly appreciated.

Flood it 3 or 4 times with water to wash fertilizer, and salts out.
You should wash salts out twice a year.
I believe a five gallon pot, with drain holes, is in order, come next year.

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Hope you'll excuse me, but don't you actually have two trees in that pot? ! They look amazing considering where you're growing it. To get fruit, you're probably going to have to hand pollinate the flowers. A tiny little artist's paint brush is the tool for the job.

I would say you desperately need to pot them up but not until they've recovered from the fert burn (putting out new leaves without burnt tips). Citrus tend to grow their feeder roots in a fine mat quite near the soil surface, to try not to disturb the top layer of soil and don't add a lot of soil on top of what's there. I wouldn't try to separate them, this late in the game. They're probably so wound up together it would kill them both to get them apart.

On the fertilizer spikes, they really don't distribute the fertilizer well at all, putting it all in one place instead of spreading it around. It would have been better for the tree to crumble it up and sprinkle it evenly over the soil surface. But still one whole spike would have been too much for that small pot. That might explain why it burned the leaves and I agree with Philip to flood it thoroughly. Look online and buy a bag of a pelleted, time-release fertilizer that is specific for citrus. (the spikes also aren't very well controlled in how they release the nutrients) After you've re-potted into a much larger pot, give the tree a light ! ! sprinkle on the soil surface in spring, summer and fall. Remember, a plant in a pot can't get rid of excess nutrients like one in the ground can.

Do you put the plant outside for the summer? For hot weather, a little bit more fertilizer might be tolerated along with increased watering of course, but still err on the side of too little as long as the leaves are a good color.

Good luck from a fellow Canadian (living happily in Florida).

Wow! Thanks Elaine and Philip for your speedy and relevant responses. I will definitely Give It 2 or 3 floodings over the next 24 hours to clean it out and I will pot it up later this fall when we bring it in. It's favorite time of year begins June 1st when we put it out on the deck and it fills in tremendously and grows vigorously. By the way, yes it is two trees in the one pot.

I highly recommend you fertilize with DynaGro FoliagePro 9-3-6. It is a complete fertilizer with all essential trace elements. I started using it last year and it's the best fertilizer I've ever used.

I wanted to thank everyone for their advice. We are well on our way to full recovery as you can see from the attached photo. There's plenty of new growth, and new blossoms so we have high hopes of Canadian grown key limes this summer or fall!!
We also re-potted it as per all of your advice... Thanks again everyone!!

Wow, they look fabulous now. Well done on the save. Get your little paintbrush ready and "diddle" those flowers once you can see visible pollen.

If I might suggest, to keep the plant growing through your short days and low light winter months you might want to invest in a grow lamp for it. Give it extra light on cloudy days, and a couple of hours more "daylight" as well. Down here, lemons and limes grow pretty much year round although they do slow down a lot if it gets cold in winter (below 40deg. F at night is "cold" right?) Mine used to bloom pretty much year round, off and on too. It died of Citrus Greening disease, sadly. Something you won't have to worry about.