Seed 12/7/13
Germ 12/12/13
DWC 'nursery' 1/25/14
NFT channel somewhere around 2/7
Harvested today 3/21

Notice the tip burn in the picture. Rest of plant is healthy. Weighed in at 446 grams

PH has crept up some lately to around 7, but mostly 6.2-6.5. Water temp is cool, low 60's (F). Air temp is around 62-64f and humidity 40-50%.

I'm using Masterblend 4-18-38... ratio 2:2:1 for masterblend, calc nitrate, epson salt (as rec'd here, thanks!), at a concentrate to get my around 700-800ppm (on a 500 scale, so 1.4-1.6 EC).

I am thinking I should be simply using EC instead of PPM, as I think 1.4 is a little high for leafy greens..

thoughts?
thanks,