Short answer: No, wait 7-14 days. Long answer: Most potting soils should have some sufficient calcium and magnesium for the first 1-2 weeks of growth, watch for any yellowing at all. Soil typically buffers pH well, especially when dolomite like is mixed in. Adding cal mag to water changes the pH. You have to test the pH after you add all the nutrients like
Calmag and grow boosters. A lot of potting soils from
fox Farm and other popular brands add it. Dolomite Lime also deposits
CalMag into the soil. Whether or not you add cal mag to also depends on your water source. Reverse osmosis, always add
CalMag. If you’re just doing tap water, like I am, you’ll have some cal mag already in there, thats why the pH is so high in tap water. In tap there’s also some chloramine, city water is treated for cleanliness. If you are using well water (ground) you will have maybe TOO MUCH cal mag and other metals. A TDS meter will read the electrically charged ions like cal mag in the water. Get this for well water, not for the other tap, distilled or reverse osmosis varieties of filtered water. If you are adding nutrients to your water to feed, you may still want a TDS Meter to make sure you’re not over feeding your girls. Again the TDS Meter helps measure all the ions in the water, like those in your nutrient feeds. This will stop you from burning them! The metal ions are measured in parts per million, the meter does this for you.
Ideal Ppms by stage: Seedling(w1)=100-250ppm. Early veg(w2/3)300-400. Late veg (450-700) Early flower=(750-950). Late flower=(1000-1600). Flushing is only necessary with bottle nutrients being used, like cal mag. So flush with DISTILLED or REV OSMOSIS water with 0 ppm if possible, done 1 week before harvest. Right now you should wait a week
As mentioned the pH is also super high in tap, 8.2. Pot plants in soil like their root zone slightly acidic, 5.5-6.5. It makes sense to water with 5.5-6.0 in veg and 6.0-6.5 in flower. I like a pH of 6.0 for veg. Get a cheap pH pen on amazon or local grow store if you haven’t. I use absorbic acid at a rate of 50mg/gallon to eliminate chloramine, and it also brings down the pH to where I need it, it’s just vitamin c. Plants actually love it, it’s a water soluble vitamin. Hope that helps y