dzk, canna: Both of you aren't understanding what I've said, in this or other threads. I've never said top dress or to add more to a container. What I've said is, please read carefully... If a grower uses a large enough container with FFOF and nothing else, there's a very good chance that the fert in the soil will be enough to last the entire grow. You say that you're adding ferts and doubt that what I say is true. You are missing my point. What I keep seeing in this forum is that growers use FFOF soil and add more fert to it, apparently thinking they have to. I'm trying to tell people that you don't necessarily have to. When growers use bottle feeding like water, feed, water, feed, or some such thing, they usually ruin the plants. So... to take out the nonsense guesswork what a grower can do is use plenty of FFOF soil as if they are using a supersoil recipe. You shouldn't have to add any fert to supersoil provided you use a large enough container as it's important to give enough ferts for the duration and give the roots plenty of space to grow. The same thing can be achieved with FFOF, but you have to use a large enough container. It appears that both are you aren't transplanting, but instead are depending on your freedom to add nutrients whenever you feel it's necessary. For most growers, this is a problem. For some reason, people feel the need to feed, water, feed, or something similar. At least canna is trying to "read the plants," letting the change of color to dictate the next bottle feeding. I would imagine that your feedings aren't very frequent. My point in advocating FFOF soil is to depend on the soil to feed, i.e., allow the plant to feed at a natural rate without forcing it to consume more than it should. It takes the guesswork out of growing. That's my point. If you do the feed, water, feed thing, you're going to kill your plants eventually.