The main ingredient in Fox Farms is composted forest humus which has a pH of around neutral 7. The added amendments drop the pH lower when pure water is added to the growing media. If you overwater, you can burn the plants from a too low of a pH or if you add their fertilizer too early. As time goes by,(4 to 6 weeks) the organic amendments will be depleted and the pH will start to rise back to 7. That's when you add fertilizer to Fox Farms and that will drop the pH back to a suitable range. Fox Farms is a super mix unless given bad water management.
I think this is what is happening to me. When I buy the Happy Frog it is so wet it's like a brick. I transplanted some autos from #1 nursery pots to #7 pots and the Happy frog was so wet, I couldn't water them for almost 2 weeks. After 5 or 6 days, the plants started showing signs of pH issues. Rotting leaves. Spots of crust. Standard pH stuff. Still, the soil was too wet to water.
I moved them from #1 to #7 in week 4. They are in week 11 and not showing many signs of maturing. Growth has slowed way way down after the transplant. Plants are tiny and stunted. In that entire 6 weeks after transplanting they only got 4 cups of water (each). Less than a cup per week and no nutes.
I finally got frustrated and started trying to dry them out with fans and such but it just too late. Autos are so non forgiving.
In a separate issue I started some seeds in some Frog in another room and after about a week of good healthy growth, some leaves are now showing crusty signs. I have started seeds in Frog a zillion times and never had this issue.
I always pH check my water and/or nutes before using. My water is about 7.8 from the tap and I use a little pH down to take it to 7.0. When I do nutes, the nutes usually take the pH down to about 6.3 to 6.5. At 6.3 or lower I use a little base to bring it back up to about 6.5.
I may switch to Promix. I have been using Happy Frog for over 10 years and always loved it but since I moved to SoCal I have had all kinds of issues. Maybe it's the new water and the way it reacts with the Frog or maybe Fox Farms changed their formula but whatever it is, it has to stop. I have had 6 or 7 shitty grows in a row because of this issue.
I poured out the last 2 bags of Frog and I have it drying on the floor in my garage. It has been drying for over a week and is still very damp. And, let's remember that I live in the desert with 20% humidity. You would think it would dry faster than this.
I am getting ready to put more plants from #1 to #7 and I am really hesitant to use the Frog again.. I understand the ProMix has no nutes and is just blank medium. If that is true, I might go that route and use more nutes to compensate.
I am like you @Creeperpark about using only water for the first 4 weeks or so. The Frog always carried the plants that far. Then, I start using the Fox Farms nute trio at about half the recommended strength.
Just lately, I bought some Fish Emulsion and some seaweed (Neptune's Harvest). And, my supplier gave me a sample of some bloom booster from Humboldt County Nutes. I am back to growing photoperiod plants and I am great in the veg stage but after a few weeks in flowering, I get a lot of yellowing and leaf drop so I am going to try boosting and amending during the flowering period to see if I can help the yellowing issue.
I am dealing with a lot of new issues since I moved like different temps and humidity levels but this pH issue is the one that's killing me. I may try the Frog one more time since I have 4 or 5 bags in the garage but I am going to dry it super dry before using it and then I can bring the moisture level up the way I want to instead of trying to dry everything out after planting.
Thanks for the tip, Creeper. I try drying the dirt next time and see how it goes.
If the dirt gets too dry will the beneficial bacteria in the soil die?