Using Solubles or Granular in AutoPots and Other Wicking Systems

Both work in AutoPots and other wicking systems. Run solubles in the reservoir (Veg A+B, then Bloom A+B, then Cake), or mix Granular into the medium and run plain water in the reservoir until Cake. With solubles, the number that matters is pH 6.2 in the AutoPot base.

pH: aim for 6.2 in the base

This is the question we get most: why does the reservoir pH drift? Some drift in the reservoir is normal. The goal is pH 6.2 in the base, so adjust the reservoir pH to whatever it needs to be for the base to read 6.2.

Read the solution in the base under the pot, not the tank. If the base reads high, set the reservoir lower; if it reads low, set it higher, and check the base again after each new batch. Any pH down works, or use RunClean in its place.

The soluble routine

1. Mix Veg A and Veg B at 4.6 g and 3.1 g per US gallon, A first, then B. Seedlings start at the highlighted label ratio and work up.
2. Switch to Bloom A and Bloom B at 5.1 g and 2.6 g per gallon on flower day 22, or when buds are about pinky-nail size on autos.
3. Each time you mix a nutrient reservoir, add regular unscented bleach (6–8.25% sodium hypochlorite) at 0.2 mL per gallon, and again every 4 days until you change the reservoir, dosed on the volume left. Order: Part A, Part B, bleach, then RunClean.
4. When a nutrient reservoir empties, refill with plain water pH'd the same way and run it for 36 hours. Then mix the next nutrient batch.

The water interval keeps buildup down, because a bottom-fed pot has no runoff to carry it out. Skip it for seedlings still below chart strength, and between Cake reservoirs.

Granular in AutoPots

Granular is the hands-off option. Mix it evenly into the medium before transplant, per gallon of actual substrate: 60 g in 1-gallon pots, 50 g in other pots under 10 gallons, 40 g for 10–20 gallons and 30 g over 20 gallons. Then run plain water in the reservoir. No A+B needed.

No bleach with Granular. It has organic components, and we use beneficial microbes with it instead. Rates and worked examples are in How to Use CropSalt Granular Correctly.

The finish: Cake straight into the reservoir

Put Cake straight into the reservoir at 3 g per gallon, alone. No flush in AutoPots and no water interval first, whether you ran solubles or Granular. pH the Cake feed to 6.2; there's no EC target for Cake. When a Cake reservoir empties, mix the next one right away.

Autos and Granular grows run Cake for the final 2 weeks; photoperiod timing is in When to Start Cake.