Question
I have a gardenia plant in my school classroom in El Paso, TX and have started to notice little webbing around the leaves and across the buds.  I read a post saying they could be spider mites and they were due to low humidity. Other problems I have such as buds dropping off were also attributed to low humidity. I live in a desert so I can't do anything about the humidity in the area. Is there a way I can provide a more humid environment?  It would probably make for a great science project if so. My students love having "Plantasia Bob" in the class, and I would like to keep it.  I have gotten 4 blooms in the past 2 months and I have new ones appearing though they take forever to bloom. The plant was a gift from 1-800-flowers and is still in its original plastic pot.  I think it is a quart size, it seems to big to be a pint but it is smaller than a half gallon.  Thanks for any help you can give me.  

Answer
Hi Lisa,

Gardenias are challenging plants even in cool, damp clmates such as the Pacdfic Northwest and really difficult in your climate.

Spider mites thrive in hot dry conditions and tiny webs are a clear indication of spider mites. Thoroughly drench all leaf and stem surfaces with a solution of soapy water - use liquid dish soap. The key is thoroughness of converge because if you miss just a few of these critters, they will reproduce and come back to haunt you.

Buds often drop when temps are above 70 degrees and if humidity is too low. So raising humidity is not enough. The best way to raise the humidity around your Gardenia is to put it in a pebble tray. A pebble tray is a large tray or saucer filled with a half-inch or so of pebbles or stones. The Gardenia pot is set on top of the stones. Then fill the saucer with water to the top of the stones or bottom of the pot. Keep the tray filled with some water at all times. As the water evaporates in the dry air, it will raise the humidity in the immediate vicinity.

BTW, misting does not raise humidity because it evaporates so quickly. You would have to mist several times every hour for it to be effective!

The pot size is fine. Flowering plants need to be quite potbound to flower so ignore all advice to repot.

Tight pots do dry out more quickly, which is a good thing, but it does mean you have to monitor the soil carefully and water thoroughly as soon as the surface of the soil is almost dry. You have lots of eyes in your classroom to help you with this!

Weekends, particularly long weekends such as Thanksgiving can be a problem for plants that need water every few days. In that case, it is okay to leave the pot sitting in some water so that it has enough to be just dry enough to water again when you return from the weekend. It is NOT okay to keep the plant constantly sitting in water.

Finally, Gardenias need quite a bit of indoor light - a north or east windowsill is best. South and west window light is a bit too strong and too hot.

Please let me know if any of this is unclear or if you have any additional questions.

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Will Creed, Interior Landscaper
Horticultural Help, NYC