What EC levels are best growing under LED?

What if my tap water is 0.8 😕

In order to answer that question correctly you need to understand what EC stands for. Electrical Conductivity of the water is basically, in simpler words, how Salty it is. It will not tell you which elements you have in the feed. That is entirely up to you. You are the one making the feed, you should know your recipe. Young plants tend to respond well in the 0.5-0.8EC range, Vegging plants usually are okay with 1.1-1.3EC and fully flowering plants will be fine at a MAXIMUM of 1.8-2EC Keep in mind, like i said above, EC doesnt tell you which elements you have in the water, if you overdose the water with nitrogen for example, even though the EC is low the plant will develop a tip burn as a response. My advice like everyone elses would be, take it slow, and see what the plant tells you. If you measure your runoff and you have a big difference, example 1.1EC going in and your runoff is at 0.6EC, you know you have to increase, reasonably, 0.1-0.2EC a day, until you reach the desired one, slowly building up to the numbers as the weeks go by. When you DO reach the desired EC, make sure you test run it for a week, and keep a close eye on the plant and how it responds. Something that nobody told me and i had to find myself and i wish i knew english well enough to explain it better, Your mix is YOUR mix, i cannot stress it enough, even if your EC level is higher than you would want it to be, the nutrient mix inside the water is what is most important. If you have a 2.2EC mixture and most of it is nitrogen then you will fry your plant if you have a 2.2EC mixture which consists of PK boosters, normal amounts of each element etc, then the plant will slowly over time adapt, assuming it is in full bloom and your environment is adequate, never go over 1.8EC unless you absolutely know what you are doing. Feel free to message me if you need more information on EC and making a mix. Hope this helped ^_^

Best answer I can give is let the plant tell you. You measure it in the feed and runoff. If the level is consistent between the two, then the plant is taking up equal parts water to nutrients. It also helps keep your pH balanced although pH can still increase slowly. If the runoff is much higher, then decrease your nutrient levels in the feed. Your plant is taking up more water than nutrients. This will likely turn your soil acidic too (low pH). If the runoff is much lower, then she is taking up more nutrients than water. This will usually raise the pH of your soil. You can increase the nutrients. Just look up generic EC levels to start at for each stage. I start around .4 - .6 and the rest of the time I'm just adjusting as she tells me what she needs. And obviously changing nutrient proportions throughout the transition and into bloom.

The perfect EC value is different for each strain. In general heavy-feeding, indicas prefer higher EC values of 2.5+, while some light-feeding sativas prefer a low EC of 1.0, or they will become over-fertilized. Water has an EC value of 0 and usually is pH neutral so 7.0 pH value.