[nmridul]

I am Just guessing. Maybe it's the tap water. It goes through multiple rounds of filteration to make it suitable for drinking and now it's poured into the soil that does not require so pure water. Or it could be the pot itself.. a large pot along with the stands and accessories to grow a dozen plants will be less green compared to open farming .

Could be that reusing waste water or using greener pots could reduce it and yet have more carbon footprint than open farming..

[archerx]

I doubt that, the water here is very filtered here (Switzerland), the stuff that comes out of these pipes makes me afraid to drink it...

[genewitch]

i cycle the rain runoff from my roof through fish ponds - well, really 100 gallon stock water tanks. I don't feed or otherwise take care of the fish, but i do add water as needed and rotate plants between all my ponds and a nearby lake (lake is only input; i never put back into the lake). The runoff from the tanks goes to fields with small hills and native groundcover, but i can grow food in those areas.

The tanks and roof added a lot of carbon, but the tanks take CO2 out of the air and turn it into nitrogen via fish poop - and plants love nitrogen.