Benefits: nitrogen

Drawbacks: soluble salts

It's the same with coffee grounds. My Dad dumps his coffee grounds on the Rhododendrons and Camellias in their front yard and they grow and bloom like crazy. But it's not really advisable to do with container plants.

My mom always used the leftover tea from the night before to water her houseplants and keep them going strong, but I'm guessing she'd have drunk all the tea but 1/2 teaspoon and then added LOTS of water. I thought I would give this a try once, and forgot about my left over tea in the pot for 4 or five days...when I remembered and looked in....yuck...mold had started to grow. I think your tea leaves would do better in the compost pile outside, or maybe collected and worked into the soil around your plants outside. The indoor plants probably don't have the micro organisms required to break the tea leaves down into something they could use, they'd be better off with storebought fertilizer, I believe.

I'm sure they're fine in the compost pile, but I'm not sure I would put them directly on plants or incorporate them directly into soils. I say this for more than one reason, but the main reason is that tea is rich in tannins, a by-product of their metabolism, and tannin is known to be allelopathic (a growth inhibitor).

Al

Thank you all for your responses. I'm glad I hadn't tried using the tea leaves yet... I'll probably just keep throwing them away since it's about a Tbsp. a a time, so not a significant contribution. I certainly don't need any growth inhibitors on any of my plants!

Chandres

I've used diluted leftover tea on my household plants, and it works well.

I wouldn't put the tea leaves or coffee grounds straight into the houseplant soil, however... I don't know about the soil not having enough bacteria to break it down properly (it's probably true) but once I tried putting in some coffee grounds. The soil eventually became very rich, but in the meantime it encouraged mold on the surface. It wasn't harmful (could just be scraped off, really, or turned over) but it is unsightly.