ButterflyEffect
Well-known member
So, this is something that's been on my mind for a while now.
What is the recommended VPD for early stretch/flower? The suggested range is 1-1.4. That's a fairly wide range, IMO. Assuming a static temp of 80F/27C, which is where my rooms are, a VPD of 1.0 puts me at 65% and a VPD of 1.4 puts me at 55%.
That all said, I was under the assumption that I'd at want to have the VPD be lower(higher humidity) in stretch at least, and then adjust more toward a VPD of 1.4 by mid-flower. What makes me rethink all of this is I know I'm seeing mild Ca defs by day 10, or so. I'm seeing not only the tell-tale signs on a few lower leaves but also fans snapping off far too easily and even some branches snap far easier than they should. It's making me think that the low VPD is reducing transpiration and thus reducing the flow of water through the plant, which naturally lowers Ca uptake.
Am I on to something here or chasing whims?
One more thing to add. I'm using stacked bare 315CMH lamps vertically. PPFD is about 7-800.
What is the recommended VPD for early stretch/flower? The suggested range is 1-1.4. That's a fairly wide range, IMO. Assuming a static temp of 80F/27C, which is where my rooms are, a VPD of 1.0 puts me at 65% and a VPD of 1.4 puts me at 55%.
That all said, I was under the assumption that I'd at want to have the VPD be lower(higher humidity) in stretch at least, and then adjust more toward a VPD of 1.4 by mid-flower. What makes me rethink all of this is I know I'm seeing mild Ca defs by day 10, or so. I'm seeing not only the tell-tale signs on a few lower leaves but also fans snapping off far too easily and even some branches snap far easier than they should. It's making me think that the low VPD is reducing transpiration and thus reducing the flow of water through the plant, which naturally lowers Ca uptake.
Am I on to something here or chasing whims?
One more thing to add. I'm using stacked bare 315CMH lamps vertically. PPFD is about 7-800.