glass cups.

[mattify]

I picked up these tiny glass cups that attach to the aquarium glass and I'm thinking of growing something in them, letting the plant spill out and down - is there something that does that, or am I just being weird?

[willie32]

Hydrocotyle sp. Japan is a great fit for this, in my opinion. It's got the right kind of growth habit. Alternatively, you could also give Monte Carlo a shot - I've seen it cascade over things before and it looks pretty nice.

[boomer]

Just a thought, plants naturally grow towards the light source. Never tried this specific setup, but I'd expect most stem plants to grow upwards from the lowest node, towards the surface where the light is. Don't think it's possible to get any plant to grow downwards, to be honest. Even my Anubias and Java Fern rhizomes tend to lean towards the light.

[coltin]

Aquatic plants naturally have air-filled stems, causing them to rise. To achieve the desired effect of plants growing over the side of a submerged cup, I'd recommend using Java Moss, then securing it to the cup. Alternatively, if the cup is above water, you can opt for a non-toxic, creeping terrestrial plant.

[barnicle]

I had the same thought, whatever plant you choose will likely just float around in the water, but that could be pretty cool in its own right. Give it a shot and show us how it turns out, I'm curious to see the result.

[willie32]

I think Hydrocotyle sp. Japan or Tripartita would be a good choice - they tend to grow outwards and creep, so with a bit of guidance, I reckon it'd spill over the edge of the cup. It can also grow as an epiphyte, so rooting isn't a major concern. Maybe just add some gravel or aquarium soil over the roots in the cup to weigh it down, and I think you'd be onto a winner.

[petal9]

I've got a couple of small plastic cups with emersed plants that are thriving, growing upwards above the waterline where they'll eventually bloom beautifully. The only plant that seems to defy gravity is moss, but if I were to use that, I'd probably opt for something like Coflake Moss or Askento4 Leverwort, they've got this lovely seaweedy effect that I think would look great.