I am using a mixture of fox farm potting would and Malibu compost. For watering I’m using RO water. I recently bought Cal Mag to add to my plants diet. Do you have any recommendations for other nutrients?
Fox farms products are kind of hot right out of the bag, and combining it with compost won't cool it off any. I use tap water for my calcium ad magnesium... it isn't terribly hard, around 225 or so, I think. With the soil you have and compost, I would think you have plenty of nutrients to last you for a while. I use
Promix, which is buffered to offset the natural acidity of most nutrients as well as the peat that is used to make it. It drains great but is lacking in most nutrients. Fox Farms is ready to go, but might be susceptible to a pPh swing unless it is buffered. Check your Ph... I like to keep mine at 6.5 to 6.7 in
Promix, watering daily. I only feed about every 12-15 days when growing max.
I use wood ashes to provide additional buffering as well as micro/macro nutrients... just about everything except Nitrogen. The possible downside is raising your Ph too much from using too much ashes (or if you were already Ph high). This is the same risk from using too much
cal-mag... the calcium raises the Ph, locking out the magnesium... Ph control is pretty important but not a problem if kept in the proper range for your growing medium. Hydro takes a more acidic Ph range, while Soils are anywhere in between 7.5 for specialty growing to 5.0 for acidic plants. But I have digressed...
You should be fine with what you have currently. Check PPMs and maybe add some, but not too much,
cal-mag if the Ph iss OK. You should be good to go! FWIW, I water about 1 to 1.5 gallon water/day per 5 gallon bucket when over 4 weeks old, but I use
Promix, which drains well. I get a slight drainage out the bottom, which insure minimal buildup of salts and fertilizer excesses.