Your first time in the Garden forum and a great, fun question that I don't think has ever come up before! Congrats on both counts.

As for an answer, I'd be afraid the water would be too salty for many plants but if you've been dumping it on the grass, then maybe not. Do you have any salt-tolerant, seaside type plants like dusty miller or bayberry? Daylilies seem to be be quite salt-tolerant. But what about a lingering odor?

Never had enough lobster to even think about dumping the water! :)

BUT, we always buried the shrimp hulls beneath the palm trees after we had a big pot of boiled shrimp. Not right up against them, but under the fronds anyway.

What do you do with the lobster shells? I think they would be like egg shells. Perhaps they do not retain much of the salt used to boil them.......

If we cleaned the shrimp raw, we always boiled the raw shells for stock, and froze it for use with another dish.

We boil our lobsters on an outside burner because I can't stand the smell lingering around in my damp humid house. We leave the lobster pot out side for at least 24 hrs to cool and then water what ever plant is thirsty. I have never noticed any adverse or positive result. kt

I water my house plants with cooled boiled shrimp water also pasta water and vegetabl water. All without any added salt. Haven’t had a problem with oder and my plants seem to like it!