Tracy, how often do you apply fertilizer? and how much water is in each tray? If you're using a large tray that holds several plants, adding a lot of water and fertilizing often, I would say it's too much.
On the other hand if you use individual trays per plant, fertilize monthly, and water evaporates quickly, this shouldn't be a problem. But I wouldn't fertilize every watering..I've done what you're doing w/azaleas w/o problems, but plants were kept outside in summer and water evaporated quick enough..Toni

I se coomon liquid fertilizer 10-15-10, but only at half dose, one tray has four five plants sitting in and the others are on their own. I have actually only started fertilizing at half dose about one month ago, and I dont water to much, so none of them have gotten too much

Tracy

Trace, well, it's up to you..(S) Come to think of it, I used to fertilize AV's via trays..but they were little round containers, still I'd fill them to the top..Toni

Continual watering and especially fertilizing via wicking (from the bottom) insures accumulation of carbonates and fertilizer salts in container soils unless you regularly flush the soil with copious top-watering.

When the level of solutes in soil water is greater than the level of solutes in root cells, water actually moves out of plant cells and combines with the water in soils until the solute concentration equalizes. When this occurs, plasma often tears from cell walls, killing the cells. The technical term for this occurrence is "plasmolysis", but we commonly know it as fertilizer burn.

Al

hmmmm.....what does fertilizer burn look like??

Tracy

It can manifest itself in a variety of ways, depending on plant material, severity, cultural conditions, and probably several more reasons. It might appear as dead leaf margins, collapsed stems, uniformly yellow or mottled leaves, burned spots in leaves/stems - even holes, transparent areas on leaves, others. It causes tissue death from dehydration and is often followed by terminal defoliation, a drought response.

Al

What you need to do is fill the tray with stones higher than you ever keep the water (which is great for humidity). Put the pots on the stones, let drain water from above-watering (much better for the plants than bottom-watering) drip into the tray, but stop the whole wicking thing. Add fertilizer to your water(ing) according to label info. and that should be fine.

I'm w/ Lucy on this, the plants should be ON TOP OF, not IN the humidity trays. I top water everything & if you do this you can fertlize it when best & appropriate w/out this kind of issue. Personally, I see no point in fertilizing from the bottom, esp. by way of evaporating. I don' believe in bottom water except for very few exceptions. I even topwater my AVs (carefully).

I also think for someone new to plants (if that's you, thought so, but not sure), fertilizer would be best 2x a month in active growth only, otherwise one really doesn't know enouugh to know what to expect the plant's plain, unfertilized condition to be.

Also, I'd switch to balanced fertilizer (10-10-10 or 20-20-20) rather than what you're using, which sounds like it's a milder bloom-buster (higher middle number).

Well big misunderstanding here.....lol. My plants do sit on the pebbles, and not in the water, but for those that I bottom water, I move the pebbles, and put the pot in, then once it has had its drink, I move the pebbles back and put the plant on top, none of my plants sit in water.....If anything I have an underwatering issue....lol....I am really quite careful not to overwater, as I have a few rare and odd plants.

My concern was a build up of fertilizers in the water, so that if I kept doing this, one day there might be some pretty potent fertilizer in there, as in theory I would keep adding water when it dries out, thus refilling my pebble tray is done more often that I water the plant....

As for the fertilizer, I might switch, I just started fertilizing my plants, so I went for the all purpose houseplant one.....that only some of the plants get.

Tracy

I too believe pots should sit atop pebbles.
Karen, I agree 5-10-5 should be sold as a mild-bloom-buster, but for some reason different brands of 5-10-5 are sold under, 'foliage or all purpose fertilizer.' I don't understand it either, but the average person is unaware of the difference in fertilizer percentages.
Wow, Trace, you really do a lot of work when watering your plants. LOL..How many do you have? If you like working with plants, take a few at a time to sink, and either hose soil and leaves, or place stopper in sink, fill w/warm water, then let plant soak up water..They really enjoy this treat in winter. Toni

Well Tracy, I just don't understand why so much moving the pebbles in & out. Seems pointless (to me) & too time consuming (I've got abt 200 plants & work fulltime). If one topwaters (even if carefully), one can just water to overflow into the pebbles. Moving the pebbles in & out like that seems too much work & time consuming, I have FAR too many plants for all that time & work.

If you're dead set against topwatering (can I pls. ask why?), what abt just topwatering when fertilizing & then just twice a month is really all that's needed. As to fertlizers, if you've just started w/ them, why not use them EXACTLY as directed but only once or twice a month, May thru Oct.? Barring unusual plants (or winter growers), that's really all that's needed.

If you're fertilzing sort of weakly, weekly (as many Orchid growers do), I'm doubtful that's a great idea for non-orchids; just my opinion.

Hoya HopefulA (Toni), Welcome back, it's EXCELLENT to see you back & posting, you're voice & contributions have been missed by many. Am hoping all (or most) is much better in yr. neck of the woods & that Spring finds you cheerier & flourishing!

(PG) Karen

I, too, want to know why all the bottom watering? Inquiring minds want to know! ;-)

I only bottom water a tray of AV's and a few of the hanging plants, as it is easier to fill the reservoir than to top water.....I am nearing 60+ plants so there is no way possible i would have the patience to bottom water them all, but for the ones that are, I ust dont want to see a build up of fertilizer in their basins.

Tracy