When is it safe to flush a youngling when ppm runoff is way to high fist week or second week?
Welcome to forum
How old is seedling?
What are you growing in?
Welcome to the forum.
Seedlings should never be watered to runoff. The water given to seedlings should be measured in ml in the seedling stage. Overwatering risks root rot.
What soil brand and type are you using?
welcome to the community
What are the readings? Soil?
Coast of main organic soil ec 6 ph 6.7
New bags of soil will have runoff high runoff values because soil has nutrients in it. You don’t want to flush the nutrients out, you want your plants to consume them. There is no need to test runoff ppm on new bags of soil, but after a month or so the nutrients will be depleted. You can monitor the runoff and when it reaches your target ppm for feeding (an ec of about 1.5-2) you begin feeding it.
If you want a growing medium that has low runoff numbers then you should grow in coco. Coco requires supplemental nutrients from day one.