besseae culture

[Rick]

Gotta be careful of comparing EC of natural surface/well waters to EC of fertilizer systems

Note that EC 1.5 mS (or mMho/cm) is a conductivity of 1500 uS/cm

My well water runs 600 to 800uS, which is pretty stout, but it has NO measurable NPK in it.

I have a potted rescue Phal on my kitchen counter that gets nothing but the well water, and its been doing pretty good (3 new leaves, and a bunch of roots).

I doubt I could get away with this by regularly watering with a batch of RO water mixed with enough balanced NPK to a conductivity of 1000uS (1.0 mMho) for very long. I've killed every potted phal I got when using MSU at 1/2tsp/gal. I think that comes out to conductivity between 600-800uS.

But the main point is that an EC value tells you nothing of the chemical composition of the matrix other than you have a bunch of ions in solution.

 

[Rick]

I'm confused a little.... Are you saying rainwater has up to 500 us/cm?

No rain water (like Brabantia's) has a very low EC.

But rain water off of dirty roofs, with leaves, dead bugs,.......will not have a low EC.

I'm presently working with a landscaper who collects "rain water" off a parking lot. He can't understand why the EC is 1500uS with a pH of 8.+ and about 1/2 of his hollies die every other year.

Rain water should have a low EC, but seems like it always picks up something before it gets in the storage tank:wink: