The benefits of worm farms are 1 for there castings and 2 for the ability to "brew" worm tea. The reason why it's called worm tea is because you need to brew it in order for the beneficial microbes to grow and multiply. Once they have "brewed" for a day or so you have essentially grown a few hundred thousand colonies into a few hundred million. Leachate is waste / excrement and depending how concentrated the leachate is you could end up killing your plant. What most growers don't understand is that the waste is not tea and you will often read that mistake. However uneducated growers will use that waste and believe there is no harm mainly because it is either not concentrated enough for to harm the plant immediately or 2 their farm is somewhat inhert and really doesn't generate enough waste from the few worms to cause any problems. However if you have a thriving 7 tier farm that has been up for a few years like I do you will see a big difference in the color of the leachate as it will be dark brown or almost black indicating the high toxic levels.
Do i actually have to "brew" it with like a bubbler and stuff? Or can i just dilute it to about a cup of juice to a gallon of water