Questions about when to add nutes to auto flowers in Happy Frog soil.

Heyyy! I'm happy to report that my first soil grow is off to a good start!

I mixed Fox Farms Happy Frog with perlite, worm castings, a couple of handfuls of beautiful, rich soil from my woods, and hydroton as a base soil. I dug about a 2 cup hole in the center and filled it with worm castings and put my germinated seeds in. They're responding beautifully!

I have them under a LED and right now am watering with plain well water from our own well which has a high ph (7.5) but since Fox Farms is ph buffered, I assume I'm ok?? So far they seem happy!

Looking ahead, I'm wondering what kind of amendments I should be adding and when? I'd like to keep it basic and budgeted if possible...

Also, should I be ph'ing my water? If so, with what? I have general hydroponics ph up and down, but obviously that's not organic.

And regarding cal-mag, should I wait until the plant tells me there's a deficiency or be proactive? I have southern ag cal-mag, but again not organic. Lots of questions!

Thanks guys!

Just water them; don’t add soluble nutrients until you are sure your plants need them. Don’t ph adjust anything. Growers choose soil amendments based on several different reasons: Availability, price, adherence to certain proven recipes, etc. There are no set rules to follow but you need to provide npk inputs (fertilizers), forms of compost which provide microlife , mineral inputs which provide macros and assist with absobtion, and soil conditioners like coco and/or perlite which provide aeration and/or moisture retention. Diversity is always good; you want to add lots of different things in small amounts.
For your first run just use the soil as is with maybe some worm castings added in. If that makes the soil kinda mucky add some perlite and/or coco coir to lighten it up and improve drainage. Keep a soluble npk source like liquid fish on hand if the plants begin to look pale but you shouldn’t need it until later in veg when they have been in their containers for awhile. When the roots begin to reach the edge of the pot go up to a larger container. Add granular mycorrhizae in the hole at each transplant.
In preparation for bloom phase transplant to your final size container and add a snow release fertilizer like chicken or cow manure. Then you can optionally push in a couple Jobes organic spikes. You can also opt to give a compost tea in the weeks just before and after they transition to flower or simply top dress with worm castings when you build up your bloom pots. That should keep them green almost until harvest. Amend and recycle the root ball after each harvest by adding in your soil amendments & compost. Hydrate & let it set 30 days and it’s recharged for another run. Your mix will get slightly better each time you do this.
Check out my thread if you want to see a list of recommended amendments. Aquire all this stuff slowly over time; you don’t need to get everything all at once nor do you need to add all of it each time. Get a few things now, few things later, and a few more things after that. You can add slightly different stuff each recycle if desired; everything breaks down slowly and at different rates so what you added may not be available to the plants for many weeks later. Some amendments like SRP or greensand literally take years to fully release.