i have a couple questions do you find sunshine mix #4 usually has pests so you have to sterilize it? i usually run pro-mix same size bale also peat never had this issue with pests. also peat becomes more acidic over time do you track the ph of your medium throughout the grow and adjust its ph with a liming agent?
Yes, SS#4 can be very buggy sometimes. So I steam sterilize it before using. H2O2 can be used instead, but I don't like to have concentrated H202 around the house. Promix is more expensive. I'm frugal. So I go with SS#4. Both are packaged in 3.8 cu-ft size and are the same price but the SS#4 is compressed and contains a lot more material than uncompressed Promix.
I check the runoff of the media before putting seeds or plants in the media. I try to start with the media at 5.5-6.0 pH. That's normally where it is right out of the bag. Occasionally it's too low to start. Rather than use lime, I use potassium silicate to raise pH. The effect is more immediate. Lime takes a while to dissolve and the few times I've used it, my pH got too high evenutally.
I do track pH and runoff PPM once a month during the grow. It's normal for pH to gradually rise over the grow even when watering with 5.7pH feed. By the end of the grow, the pH is usually right at 7 without any deficiencies. I feed fairly aggressively, so I keep an eye on the ppm of the runoff. Flush down to 800ppm if the runoff gets above 2500ppm.