Your plant has severe nutritional deficiencies that might be a result of ACTUAL deficiencies (not enough of certain nutrients in the soil or soil solution) or because of cultural conditions (plant may not be getting certain nutrients because one of several possible cultural conditions are preventing uptake).

The spots are likely a symptom of the same adverse cultural conditions and are probably related to the effects of over-watering.

What have you been doing as far as nutritional supplementation? Are you allowing the soil to become quite but not totally dry before watering, and then do you water thoroughly so lots of water exits the drain hole?

Al

Posted by tapla z5b-6a mid-MI (My Page) on Mon, Feb 10, 14 at 14:56

I completely agree. The plant is suffering from wrongful culture methods and conditions, notably over-watering and severe nutrient deficiency. This is not the result of one day malpractice.

I notice you mention re-potting. Why? Why would you re-pot it in such a situation? Gardenia resents disturbance of root system. Where did you get these wrongful ideas that would kill a healthy Gardenia?

This post was edited by jujujojo on Mon, Feb 10, 14 at 15:52

Gardenias might resent untimely repotting, but they appreciate repotting along with root pruning when they're root bound, if the work is done in spring. I would suggest the OP probably should root prune and repot into an appropriate soil (one that allows proper watering, i.e. flushing the soil w/o worry the soil will remain saturated too long), and move the plant outdoors, as long as there is no danger of freezing temps. Fertilize with an acid forming fertilizer (like Foliage-Pro 9-3-6), and if the water used for irrigation is high in carbonates, acidifying it might be appropriate.

Al

Posted by tapla z5b-6a mid-MI (My Page) on Mon, Feb 10, 14 at 16:10

Al, are there Gardenia growers in Michigan? I did not know any. I thought these are really lovely.

Again I agree with your post. I just need to clarify that the specific plant of the OP is unlikely to be root bound. Gardenia hold buds over winter and spring. So, the best time to re-pot and prune is in early summer when the temperature arises sharply and flowering subsides. The heat will also help Gardenia to recover.

.... may or may not be root bound, but the soil may well be inappropriate (and likely the cause of cultural issues leading to symptoms). From a physiological perspective, spring is the best time to repot gardenia.

Let's wait to see what the OP has to add ....

Al

AI-
The soil is Organic Edna's Best Potting Soil. I was feeding it bi-weekly with "Plant Nutrient" (1.2% nitrogen, .05% phosphate, .35% soluble potash, 1.08 kg/l specific gravity) but have stopped for 'winter', January-March, to generate new growth in the spring. I water only when the top two inches of soil are dry and then water through completely twice, allowing it to flow through the drain hole, stop, and then once more. Unfortunately, outdoors is not an option as I live in an apartment, but perhaps root-pruning would help? I also am in Los Angeles, so it's quite warm all year round.

JuJuJoJo-
I repotted to an 8" pot because it had overgrown it's original 6" pot and the roots were coming out the bottom and becoming exposed on the top (with no room for additional soil). It's the only repotting I've done on this plant and I've had it for a year (no telling how long it'd been in the pot previously at the nursery). As I said above, I only water when the soil is quite dry for the first two inches of topsoil.

See previous discussion:

Posted by butterfly4u 8 (My Page) on Tue, Jan 14, 14 at 23:47

Jacobean,
Get the water out from underneath it!
They can't have wet feet like that.
You are watering it too much.
When was the last time you changed the soil?
Was it a year and a half ago?
Just wondering.
You mentioned a water meter, remove the water it is sitting in and don't water it until the water meter says dry after you put it down near the roots of the plant.
The easiest way to improve drainage until you repot it and refresh the soil is to put it in another pot, bigger filled with potting soil.
Pot in a pot, for right now, til you can put it outside.
Good luck to you.

The entire post is here.

Also, I would recommend the OP to post picture of the entire plant.

In the OP, it was mentioned that the plant was above a "rock filled water tray ... for humidity. I hope it's not sitting in its own effluent that collects in a drain saucer.

Using a wick, like mike suggested, would be less effort and will accomplish the same thing as employing the pot-in-pot technique. The problem with pot-in-pot is, the water in the soil of the larger pot is going to stay there until it evaporates, and I can see some potential problems associated with anaerobic decomposition in the larger pot's soil.

Skip the water meter. Buy a 1/4 or 5/16" wood dowel & sharpen it in a pencil sharpener. Use THAT to test the soil for moisture. Push it deep into the soil - if it comes out damp and dark or wet - no water required.

The fertilizer is appropriate insofar as the NPK ratio, but what else does it contain? Reading the ingredient list of the potting soil and assuming the ingredients with the highest volumes are listed first, it HAS to be extremely water retentive - which means you can't water appropriately w/o risking root rot or at least impaired root function.

You can't move it outdoors, but that's where it WANTS to be.

Here's the thing - bottom line: The plant is obviously suffering because it's being forced to deal with cultural conditions it's not genetically capable of dealing with. If you can't isolate and fix the issues that are causing the decline, it will continue, so you'll need to go back to the drawing board and look at the big picture. The first considerations are checking for insects & root problems/disease, and making sure the plant is in an appropriate soil (if it's not, your watering habits need to be adjusted so they allow for a poor soil) and in the right light/temp range. If these issues don't come up in the favorable column, there isn't a lot of sense in chasing it much further until you're willing to take charge and make some changes. That might sound harsh, but it's just how things are.

Al

JuJuJoJo-

I changed the soil when I repotted it, about two months ago. I've felt in as much as I can through the drainage hole and the soil doesn't feel damp, much less wet. The rock tray it's sitting on isn't touching the bottom of the pot. I've attached a photo of the entire plant (immediately after it's last watering, thus why the soil is wet). I'm not an authority, obviously, but I have about 15 long-lasting houseplants ranging from succulents to ferns and have never had over-watering issues before. I usually wait for them to 'tell' me they need it, then run them through twice. You're sure it's overwatering?

Al-
So maybe the sad truth is gardenia's just don't do well indoors? I'm happy to pull him out and take a look at the roots if the consensus is over-watering or root rot as a result of overwatering, I just want to be sure so I don't do anymore damage.

Posted by mielwade none (My Page) on Wed, Feb 12, 14 at 16:56

If your fern is doing okay, then you have good humidity.

I think this is chlorosis. Like Azalea and Jasmine, these plants like the soil to be acid and free from salt. Depends on where you are, your tap water can be salt softened, like in Wisconsin. That water kills gardenia.

Buy distilled water or use RO water. Mix in water those acid fertilizing products - those bluish green crystals. Use only half strength with each watering.

Also buy those slow release acid plant fertilizers - the brownish or greenish beads. Mix into the top 2 inches soil well. Use proper quantity as instructed by the product.

Do not pull the plant out at this time.

If you are in winter now, you can expose your plant to South window all day.

If you plant still looks like the picture, it will slowly recover. Newly grown leaves, should be green immediately.

Thank you so much for the insights! I'm going to the nursery right now for some acid fertilizing crystals and slow release acid fertilizers, and maybe if the fates allow, I'll see some blooms yet!