New Grower Soil mixture ?

[Ozzy3277]

Hi AF World . I am new to AF, but not new to GROWING. This is my first AF grow so I want to get it right the first time, and with your help I know I can do it.
My question is, the soil I am going to use is 3.8 cubic ft. of (PRO-MIX BX) .I also bought a .5 cubic ft. bag of (ALASKA HUMUS SOIL AMENDMENT 100% ORGANIC) to mix with it. How much, or what ratio should I mix these together? I was told where I got it to only mix .25 cubic ft. of the humus soil with all of 3.8 cubic ft. of the PRO-MIX .Do you think this is enough humus soil, or should I just mix the whole bag with the PRO-MIX.
Also if your wondering why I am using the PRO-MIX BX instead of the PRO-MIX HP It's because I am using 2-400w HPS.
Please give me some input , it will be greatly appreciated,THANKS

 

[az2000]

I would use a scoop that's close to 1/2 to 1 gal in size and think in terms of scoops (not mixing entire bags, unless you have a large operation, large mixing container, etc.).

You don't have to add soil/humus. Many people grow in Pro-Mix alone. I add Kellogg Premium Patio Potting Mix to my Pro-Mix HP (I use t5ho or LED lights, it dries out in 2 days). I do 3 scoops Pro-Mix, 1 heaping scoop Kellogg, 1 shy scoop perlite. That comes out around 60% Pro-Mix, 22% Kellogg, 18% perlite.

My scoop is 2/3 of a gallon. So, after those 5 scoops I have 3.3 gallons of medium. I can then add 3.3 tablespoons of dolomite lime to stabilize the ph.

The only reason I added potting mix was because it was my first grow (last September) and wanted what I thought was the best of both worlds (soil and soilless). It was more driven by fear that I would mess up a purely Pro-Mix grow. Back then I asked Muddy and he said 20-30% should be ok (might even improve the ph of Pro-Mix which is 7, according to him. I've never measured it.).

The only thing I don't like about my medium is how hard it is to wet a new container for planting. Water runs straight through. It takes 12-24 hours of letting the water soak in, pouring the runoff (from saucer) back through a dozen times.

 

[virginia gent]

Hello and welcome. I use promix ultimate and feed with trio, cal/mag and superthrive under T5's and LEDs. Spray the soil well while filling the pot, tamp firmly and good to go. Feed 1/4 recommended amount at about the 10 day mark, with autos you only get about 4 weeks of good growth before they start bloom and vertical growth stops. Nute burn and over watering seem to be the most common problems. If you spray the soil while filling the pot it seems to help let the water soak instead of running through. Good luck and good karma.