Seems to be a bad Phosphorus deficiency mid-flower.

[Rusty Trichome]

The potting soil says nothing about added nutrients or time-release, which is why I buy it. It is one of the few non-time-release options in this area...most places sell the time release national brands. link to <a href="http://www.fafard.com/index.php?p=14">soil info</>

Was just checking. (covering all bases)

I grow indoors, in a 3'x3' 'hydro hut'. Thanks for the clarification on flushing. I can handle three gallons of water for flushing if that is enough to counteract the FoxFarms salt build up (if, indeed, salt build up is a problem here).

I flush monthly with 1:1 volume to gallon. But I do add Soil Syrup with the nutes on flush day. (humic acid)

I use RO because my well water is quite hard. TDS ranges from 250 to 280 and white and rust deposits are all over the plumbing. pH of raw tap water ranges from 7.4 to 7.6.

My tap is 7.9 to 8.0, with a hardness of 240. Underground is calcium carbonate. I use my tapwater, and simply adjust ph with phosphoric acid. (phDown by GH)

The pH Meter is an 'UltraBasic' model that does single-point calibration. I do check calibration every week, usually the meter is spot on. The margin of error may mean that if the solution is 6.5 the meter could read anywhere from 6.3 to 6.7...which is why I shoot for 6.5 for all my input water/ferts.

Okey dokey.

As for the FF ferts., I stopped all soluables two plants ago. I use one tsp of CalMagPlus per gallon of RO to replace minerals. I've been feeding half-strength (by the FF chart) every time the pot is dry. Thing is it takes 5 days to get light, so they're not really getting the full dose every week. My grow environment is pretty humid...never drops below 50% in my basement during summer. These are approx 3' tall (after stretch) plants in 12" plastic pots with extra holes in the bottom. Am I just waiting too long to water, or maybe I need a dehumidifier to bring down the humidity and speed up transpiration? Soggy soil? The FoxFarm schedule for weeks 7 and 8 (3rd and forth week of 12/12) says to use both GrowBig and TigerBloom. Do you do this? Just cut the liquid dosages in half?

Ok...
Molasses is cheaper than CalMag. (made from cane sugar molasses, with a little mag for ph control, I believe)

For 6 - 3 gallon pots I will adjust my water to 6.8ish, and add a quart to each pot. Then, I mix my half-strength dose, and some molasses and give each pot a quart, added slowly to maximize absorption. I do this on Mondays and Thursdays. Plain ph'd water inbetween. I use the 'inbetween' times for flushes, any additional watering if dry...
I stick pretty much to the schedule including the Grow big bump on week two of flower, but I grow mine a tad taller than you. (gives a little stretch, but fills it in nicely)

Soluables are ok at 1/2 of the dose per the schedule, but that is strain dependant. Some don't take it well.

Kick-up the fans if too humid. Make 'em aspirate rather than leaving the humid air to stagnate.

- Use your reccomendation of BigBloom dosage for Veg and Flower
- Use your reccomendation of molasses dosage for Veg and Flower
- Start feeding more often. I've always been afraid of soggy roots so I wait till the top of the soil is quite dry. Perhaps I'm waiting far too long.
- Flush with 3 gallons of pH 7.0 water next time I see the leaf margin curl and color change.

- Yes
- Yes
- Yes, but on a regular schedule.
- Kinda. Try not to let the ph sway, and try not to let the roots touch pure lime till dissolved into soil. (are you by chance using used soil when the ph dives?)