Having a 50W COB a foot away from a plant is too close. I'll guess that 2-2.5 feet is more optimum. (I don't use COBs, so I'm guessing.) A pH of 5.5 is too low for soil. It's even a little low for hydro. Google "soil ph chart for cannabis". How's your temperature at canopy height look? When the leav...

The bottom has the classic look of Mg deficiency. How much CaliMagic were you using?

Usually folks that grow in soil don't use H2O2 as it will kill the beneficial bacteria. I use it in my hydro storage tank, but only at 1 ml/gallon. What are you using it for?

"I haven't researched much on RO and when it's actually needed, I'll read up on that. My tap water is around PH 6, and 200 PPM...so I'm thinking it's not that bad?" My water is 280 ppm (on the 700 scale) and pH 8.1. I grew with it (in straight perlite in Hempy buckets) for a couple of years before s...

That's quite the comprehensive shopping list for a first effort. Looks like you've got all the parts. How is your water? Will you need an RO unit too? When I look at your pics, it seems to me that you've built a light for a rectangular tent, not a 5 x 5 square tent. How does the light distribution l...

Seems like when I search the web for VPD, I get a whole lot of recent search results involving cannabis. One could get the idea that it's a recent thing, like someone invented it just for cannabis. But looking further, this started a long time ago, with other greenhouse plants, here's a link to toma...

The whole VPD chart thing scares the crap out of me. When I look at the chart, it appears that I've being growing in the VPD equivalent of a desert for a lot of years. The general consensus at the time I started growing indoors was about 35% RH for flowering. It's what I've tried real hard to achiev...

Sure, Professor.

With nothing in the way the Fluke 87-5 meter and Apogee SQ-500 showed 241 umols, the lens filter was 230, tape was 227 and the plastic cover was 219.

I was kind of curious about losses... so I did a little testing. I cut off a toilet paper tube about a cm longer than my quantum sensor and with some tape, made a fixture to support various pieces of clear stuff above the sensor. This assembly was put about 3" below a daylight CFL in a cabinet. I di...

So, all you guys using Quantum Boards... Do you use a plastic cover over your boards?

I use a Bluelab combo meter and have had to replace the probe once when I smacked the tip against something. The replacement probe from the local hydro store was fine.