Pre soak soil?

i'm using lightmix and i think is perfect without pre soak, what they suggest to do is fill with water without loosing from bottom hole only for drop nutrients on bottom of pot and don't allow plant to reach for firstly 2-3 days... this situation is essential instead for royal mix ... i prefer don't add anything to this mix (if is version with perlite) and if you add perlite, wash it first, it's so important.

Cant hurt , seriously no risk and possibly some reward go for it.

To my understanding it's best to flush soil and peat (plagron all mix is not soil, but peat.. that's considered "soilless" - that's important for feeding) when they are heavily pre-fertilized to not cause any overfeeding or shock when transplanting.. It will basically flush the immediate nutrients out, and the slow-release nutrients will stay in (and slowly release them over time) the longer you wait, the more of the slow-release nutrients will be back again.. Looking at their homepage, the all-mix has an EC of 1.5 to 2.2 mS which in my opinion is really high, so i definitely recommend flushing the medium quite heavily before putting seedlings in there. That's more what my hydroponic plants get (which i keep below 1.4 in the small box) I'm using royal mix in one of my other grows, and that has an EC of 1 to 1.6 mS and those plants i have put in there after leaving them for a week or so in regular soil (and then transferred them whole with the soil)

Airpots*