Q.Watering indoor gardenia
My plant is sitting on pebbles in a tray. Could I water from the bottom to create more humidity?
Since it's sitting on the pebbles, the roots likely won't be able to take up enough water to sustain them, so you'll either need to water from above or place the plant in another saucer-like pot filled with water to allow it to suck up the water - normally about 30 min. or so. Discard the leftover water and place back on the pebble tray. To increase humidity, the pebble tray should suffice (and this can be filled as needed for humidity, just not relied upon for watering) as will misting. For additional help with increasing humidity, this article has some suggestions: https://www.gardeningknowhow.com/houseplants/hpgen/raise-humidity-for-houseplants.htm