help

[misterjersey]

these girls are greenhouse grown. soil ph is 6.5 i need to do a runoff ph test. rust or brown spots show on green leaves then yellow and die. spots almost look like a black mold as the leaves yellow started 2 weeks ago and i don`t know how to remedy fert is petes at 1/4 strength the green house gets quite warm + 80 degrees

misterjersey Reviewed by misterjersey on 07-08-2008. help these girls are greenhouse grown. soil ph is 6.5 i need to do a runoff ph test. rust or brown spots show on green leaves then yellow and die. spots almost look like a black mold as the leaves yellow started 2 weeks ago and i don`t know how to remedy fert is petes at 1/4 strength the green house gets quite warm + 80 degrees Rating: 5

[stinkyattic]

Bigger pots, lighter soil, and you have a K def.

[misterjersey]

hey stinky,I`ve soil tested for NPK and always comes up depleted in N P is sufficient and K is surplus. What locks out the K and what should I do to help the girls? The pots are 7.5 gallon , the soil is supersoil and what can I do to enhance my girls developement?

[stinkyattic]

Probably you're locked out by your low pH. Run a flush on those plants, aiming for an ultimate runoff of 6.7-6.8, feed immediately with a complete 'grow' fert (I assume you are not using auto-darkening in your greenhouse and are therefore in veg stage still?) at 1/2 strength, then let the plants rest until they use up the soil moisture. You'll then want to re-pot up into a 10 gallon tub with LOTS of drainage and nice LIGHT fresh soil- a quality compost with lots of perlite mixed in is one excellent choice. You're in the Northeast; check Agway for 'manure and humus' and mix 1- 40# sack with 1-6 quart sack of perlite. That's just one option. You can also go soilless; ProMix is very easy to find.
Then, your ferts. You need a cannabis-specific fertilizer for best results. Some that I have liked have been Botanicare's Pure Blend Pro Grow, Botanicare's Power Plant, Canna Vega, or organics. For organics, seabird guano is a high N, and so is fish emulsion. I still like to give a micronute supplement as a foliar feed using simple organics. The one I use most often is GH Micro. It's SUPER cheap and I can't even list all the times I've used it to fix deficiencies while trying to sort out their origins! It's a full set of micros, plus a little bit of Nitrogen. That would be a GREAT help to your plants as they appear at the moment. Mix it up half strength in a spray bottle with one drop dish soap. Mist lightly in the morning sometime after the mornign humidity has dropped and before the hot part of the day.

You're definitely low on N though.