pH your water to 6.5
My tap water is 8pH cause the Shenandoah River is our city water supply.
Takes 1 ml pH down to get to 6.5 - 6.6.
Also get some Epsom Salts. The Garden version that Pennington sells at Lowes.
I mixed 1 gallon of tap water with it and then measured the pH then used the pH down accordingly. (Epsom salts do not affect pH.)
I watered mine on week 3 with them. The girls exploded in a darker green since Mg is major for chlorophyll making them green
Epsom Salts is organic even though it can be used in hydro because it comes from a hot spring in England.
Also gives Sulfur too.
You can use oyster shells from Down to Earth or their Crap or Shrimp ferts that are awesome for vegetative growth and Calcium.
Either way people have to go Dolomite Lime (Ca + Mg) + Sulfur (Epsoma Soil Acidifier from Lowes) its organic. I am doing all organic my first grow right now and its awesome.
Or they go Epsom Salts (Mg + S) then add Calcium from Aragonite, Ground Oyster Shells, Calcium Nitrate or eggshells.
Or you can go Gypsum (Ca 20% + S 16%) then add Epsom Salts for Mg
Either way any of those above can be used combined in the right ratios or alone to amend soil before planting in final pot or to fix deficiencies.
Also getting a deficiency poster is helpful.
The Sulfur in Epsom and the Epsoma Soil Acidifier will help lower your soil pH.
There is soil test kits sold at Lowes (Like $12) or on Amazon.
The one at Lowes gives you 10 pH test, and 10 each of Nitrogen, Phos and Potassium.
Iused it to test the Phos and Potassium levels of the banana tea I made by soaking washed organic banana peels in purified water in a lock lid jar in the fridge then strain it.
Going to use it for ferts during mid to late flower along with blackstrap molasses.
The smell so far of the plants is amazing using organics.
Just remember pH the water down to 6.3-6.7 range to prevent lockouts.
Always check pH after adding anything to your water for feeding and adjust accordingly.
Don't overfeed. Sativas are generally lighter green than indica varieties too.
Sative - lighter green, skinnier leaves. Tall and less bushy. Indica - Wider leaves and darker green. Shorter and bushier
That Dr Earth Pot of Gold is 3.3 pH after adding to 1 gal of my 8pH.
Took 32 ml of pH UP to get it to 6.6pH. Then boom the girls got nice and darker green. I gave 1/2 dose to the 2 autos.
The Super Skunks loved it. Next grow I am going hydro to try it out for the heck of it. I bought all of
General Hydroponics nutes for that grow on Purple Kush photos.
Good Luck on your growing and follow the guys on these forums. They have lots of experience under their belt.