Guttation: healthy, or a sign of over-watering?
My Epipremnum (aka "pothos") has been guttating. (I guess that's a verb. You usually see the noun form.) I wasn't worried; when I heard about guttation years ago, it was always talked about as though it was normal. But I'm still in learning-binge mode on my houseplants, so I did a search.
Several of the posts here about guttation said it's an indication of over-watering. My guess is no, but of course that's coming from no experience, so I'm asking.
First of all, is there really even such a thing as over-watering? I sort of thought there was only inadequate drainage, sometimes compensated for by scant watering. And for some plants in some situations I think there can be soil ecology issues, where the plant's favorite mycorrhizae will be displaced by other soil microbes if the soil doesn't dry between waterings as much as the mycorrhizae are used to.
I haven't re-potted my pothos since it was given to me, and I didn't ask what the potting medium is. But it seems adequately coarse, the pot doesn't seem excessively heavy after watering, and the plant is growing at what seems to me like a normal rate.
Another thing my search turned up is that guttation fluid isn't unmodified xylem sap.
The leaves are getting mineral nutrients from that sap. Salt, in the terminology of the article, but the authors are talking about osmotic potential, not sodium chloride. So I think the plant is doing it intentionally, sending up the minerals to the leaves, and disposing of the excess water (along with anything else in the sap that the leaves can't usefully remove).
Another thing that makes me think so is that only the last couple leaves at the end of the shoot were guttating. Those leaves are presumably still growing, and need the minerals.
This post was edited by dsws on Wed, Jan 9, 13 at 3:05