Nutrient Problem?

[santos]

While my outdoor experiment gets munched away by some unknown pest, i also spotted a problem in my growroom in form of yellow spots.

 

Indoor

Growing Medium: earth

Growing Style: ?

Watering/Feeding Frequency: every 2 days

Nutrient Strength (PPM/EC): no idea, following a chart, see below

PH Levels: testing it every time i fetch water from the "cisterna" (rain water); the ph tester tube is yellow with a hint green when im done adding nitric acid to the water (supposed to be close to optimal ph)

Temperature/Humidity Levels: day 30-35 celsius, 15-25% hum; night 15-20 celsius, up to 55% hum

Air Flow/Fans etc.: orcano like from bottom air let ins in floor, to top extractor. and a very weak fan blowing inside (removing that one in flowering).

Lighting Type (CFL/HPS/MH etc.): 400w agrolite (for veg phase MH atm)

Total Wattage:400w

Growth Stage:veg

Plants Age: went into grow room on 15.04.11

Cannabis Strain: moby dick feminized from Dinafem

 

I spotted the yellow spots in 2 plants. Not much yet but i'm sure they weren't there 2 days ago. Here some pics of the fert chart, the ferts and the plants. The earth i used is very nutrient rich already. I also add some CO2 into the water in order to make the plants more heat resistant (and increase yield later in flowering). Currently i only use the Bio-Grow, but until 2 days ago i also used Root Juice.

 

Its my second indoor grow in this tiny growroom. Last yield wasn't huge (about >250g with 400W lamp) but the buds where massive and almost dripping with resin. It was 3 years ago though and unfortunately i forgot the strain i used back then, but the Moby Dick also looks promising.

 

The airpressure is probably a bit lower in there as the 2 extractor fans are quite strong and the door gets "sucked close" when almost closed. I read somewhere that weed growing higher up the in mountains has less yield but more resin/potency. That and the temperature are reasons for the "underpressure"/extractor setup.

 

I suspect though that the yellow spots are related to the nutrients. I'm leaving away the root juice now. Could that already be the solution?

[Frazz]

heya santos welcome to OzStoners

great setup you got there, and thanks for all the details and pics ..

 

im thinking your problem might well be linked to the use of nutrients at this early stage

as you said soil is rich so it will take the babies some time to exhaust all the nutrients present within the soil

the babies appear to want for nothing more than what the soil is providing now

 

it can be problematic using extra nutrients in soil at anytime due to a gradual build-up of salts within the soil

hence it is advisable to flush the soil with plain water from time to time when using such additives

 

all the best with them

[santos]

Thanks for helping

 

How often would you flush them? Would once now and once half way during flowering be fine? I'm 2 weeks into veg phase, but with 18cm they are not yet tall enough for flowering. I think ill give them time till they reach at least 35cm. Cant let them get much bigger cause the cupboard isnt very high, will probably have to tie the main buds down to maintain distance to the hid (BDSM buds ). Right after flushing i can provide them their nutrients again though?

 

I guess im kinda lucky then that i didnt up the fert doses by myself. I was tempted to do so because i read in a couple places that Moby Dick likes more fert then others, but maybe this was meant for late in the flowering phase. I use the same ferts as in my last grow though and the last plants did not have any yellow spots.

[wietlover]

if ya are nuteing them you should flush at least every 10 days min

to prevent salt build up

good luck wiet

[santos]

i did flush them and everything seems fine so far. i used water of roughly ph6, but a friend suggested i should use about 2-3 liters of ph4 water per plant. and afterwards directly water of ph 6.5 (for flowering) with half of the regular nutrients.

 

is using a that low ph realy a good idea?

Edited May 14, 2011 by santos