First
I mean over watering is a symptom right so how do you justify flushing. I would like that explained if possible.
Over-watering causes certain symptoms. Mainly your plant "suffocating" in water that has no dissolved oxygen in it.

It should be much harder to overwater a plant in a soilless mixture, which should wick moisture around effectively and maintain tiny air pockets for root health. Otherwise, why use it? (Unless you just want to be responsible for providing all the plant's micronutrients. ) Some of these media are designed to be watered up to 4 times a day, and it would take Mike Nelson to actually drown a plant in most of this stuff.

Soil's another story. If you properly water to even slight runoff, your soil should be well-saturated. That's why you are supposed to let the soil dry slightly between waterings: so the roots can get some air. Plants that have been "loved to death" typically look like they've been drowned by being continually watered -- without ever letting the soil dry enough to supply oxygen to the roots.

That's one of the reasons to keep transplanting into slightly bigger containers, rather than planting a seed in a big ol' pot and just letting it "grow into it. " Let's say you water that big pot on the 1st of the month. On the 15th it's still soaked because your little seedling has only a 2" taproot and can't suck up all that water. It goes "stale"--no O2--and your seedling drowns or is attacked by anaerobic pathogens.

The problem is compounded by letting the water sit overnight, or boiling it, without reoxygenating it. It's like putting a plant in a bubble-bucket and then standing on the air line. :wtf:

So whether you saturate your soil for 10 minutes with a watering, or for 30 min to do a flush, it's still gonna take a couple days to dry out. Saturated is saturated. If you worry about the added 20 minutes of flood time during the flush, shake your jugs (woo-hoo) while you flush to keep that water fulla O2. :thumbsup:

Overwatering is a chronic condition--one flush is not going to cause it. However, flushing with wild abandon can cause compaction of your soil, and wash out all your expensive worm poop, bat poop, and buffers, and is best avoided. Measure your runoff and quit flushing when your numbers are right. :thumbsup:

IMO, there is more to watering soil than just slopping juice into a pot. Done right it competes with hydro, if other variables are optimized.