I've read a lot about raising humidity inside by placing plants on a tray of pebbles & water. My problem is that I have way too many plants for that, not to mention, some are really HUGE. All my tropicals, including Hibiscus, Alocasia, Colocasia, & Philodendrons, all love me, but all my ferns are really disliking me right now LOL I have 2 Silver Lace Ferns, 1 Rabbit's Foot Fern, 1 Blechnum gibbums, 1 Bird's Nest Fern, and 1 Mahogany Fern.
Anyway, do misting the leaves really help with humidity? Also, can I use a pebble tray or 2 w/ water and set them on the floor behind the plants, or under the plant stand, instead of setting 1 or 2 plants on trays? Will it produce the same effect if done that way?
I also have a humidifier which I use once a day until the water runs out, which I alternate it between 2 rooms, cause as I said, I have a lot of plants LOL
The trays don't have to be directly under the plants to raise humidity...water evaporates and that raises humidity...I don't have the room for a lot of trays either. My solution was to take a few disposable plastic cups, fill them with pebbles for weight and add water. I tuck them in and around the plants on the stands and fill them when I water. For those plants that need high humidity, I just mist them daily. Sounds like the humidifier should do a fair job of keeping the humidity up.
If you're using a humidifier I doubt you'd need anything else for humidity even if you're not running it constantly. So if you're having trouble with some of your plants I wonder if it's not due to something other than low humidity. Can you post some pictures? First thing I would check is whether the plants are in the direct path of a heating vent--that tends to make plants very unhappy to have that warm dry air blown right on them. Or if you've got a cold draft from a window, or else a draft from a door that is opened/closed frequently that could also cause problems, although given your location I don't think it's likely cold enough yet for that to be the problem.
I rotate the humidifier between 2 rooms, sometimes once a day, and sometimes every other day. So, I wanted the to use the pebble trays for the room/plants during the time the humidifier in is the other room. My ferns are positioned away from drafty doors, but it seemed like no matter where I put them, a ceiling vent was aiming at them because we have a ceiling vent on each side of the room. The only alternative I had was to put them on tables in certain areas, shut the vent above them, or aim it as far away from them as possible, but then they would receive direct sunlight from the east for a few hours.
I'll break down each fern in its own post & describe the issues along with pictures:
Rabbit's Foot Fern: New, center fronds grow and begin yellowing when it reaches about 2 inches in height and the middle of the fern is becoming bare because of this. Older growth is green and appears healthy. I mist it at least once a day and it sits on a pebble tray out of direct sunlight. If the soil doesn't stick to my finger when I put it 1/2 way in the soil, then I water until it runs out the bottom of the pot.
Did fine in a bright bathroom for awhile but one day I noticed a frond had a brown circular area near the tip of a frond. I cut it off and within the next few days began noticing some tips were browning and some were crispy. I watered good (but not in the center where the crown is) and made sure it wasn't in the pathway of the overhead vent. It wasn't. However, the entire wall behind the counter the fern was on, is one big mirror which faces the window. I thought maybe the sunlight was reflecting and burning the tips. So, 2 days ago I moved it to the corner of my bedroom to the bottom of a plant stand, and even though it is by an east and south facing window, it is far below the windows where the sun doesn't reach, but would be sheltered from direct sun by a lot of surrounding plants anyway. The ceiling vent above this area is closed, and even though it receives no direct sunlight in this position, it does receive high, bright light. I hope that this turns out to be a good place for it. I also mist daily, but not on the crown.
About 3 weeks ago, what was a healthy fern suddenly had some fronds defoliated overnight thanks to some caterpillars! I removed them, but also found teeny tiny babies lurking here and there. I gave it a good bath, sprayed under leaves as well, and then sprayed with dormant oil all over, including in the soil. I haven't seen another caterpillar, or had any fronds chewed upon since Within a week, the remaining healthy, untouched fronds, began to discolor and turned a brownish-grey, which I chalked up to too much dormant oil spray, or being sensitive to it. However, they felt very dry to the touch, but were not brittle. Soil was moist. A week or so went by and new fronds continued to grow, but eventually would turn crispy and die. So, 2 days ago, I noticed that one really green emerging frond began to brown at its tip, so, I gave it a good watering and it seems to be doing ok, and hasn't browned any further. I mist it at least once a day. (I think the problem with this one was a combination of under-watering and reaction to the dormant oil spray).