No one?

Does your fertilizer contain micro-nutrients?

According to the label, yes, it does.

Hmm, very odd then, that was all that came to my mind..lack of nutrients.

What is the difference between the new and old mix? Assume they were growing ok in the old mix?

It was made os compost mainly, it was very water retentive, now it has a lot bark and mineral matter

Yes the bark is fresh, I am using 15-05-05 formula. They are outdoors for the autumn which, in Brazil, is when the plants can withstand the heat well. I used more peat for them for along time and they grew well. The thing is I have a lot of rain here and I was losing a lot os plants for the rain. With this mix this does not happens anymore. The hoya and fern soils are adjusted for their needs. The thing is perlite is not sold around here, live in a very small city, so I make do with peat, bark, charcoal, and things like that, But I think the fresh bark is realy binding the nitrogen, I will just wait and continue my routine of fertilizing until it starts to grow well again. Thanks a lot everyone! ! ! ! ! ! !

Did you adjust for pH?

Yes, I did adjust. Today My Hoya began putting out new leaves so I am calmer haha

I think I will just wait for the nitrogen to be released again to the plants and keep fertilizing

you might also search in hawaiian and florida forums: they have somewhat similar downpour situation and heat in summer. from what i remember they avoid bark: it decomposes too fast. just grow in lava rocks (scoria..pumice all similar) and then fertilize with time-release granules. rain washes out all fertilizer fast.

Thanks!!! I definetely will. Next time when is repotting time I will make a much better mix and buy some slow release fertilizer

Bark does not tie up nitrogen, fresh wood (the flesh of the tree) does. Bark based potting mixes are extremely popular and successful and suitable for most kinds of plants. Conifer bark is also highly resistant to decomposition.

Hmm, that means it must be something else?

quoting al here ;)

Fresh bark will immobilize more N than composted bark, but you can fix that by fertilizing more frequently, something easy to do because of the fast drainage

https://www.gardenweb.com/discussions/3335091/fresh-or-composted-pine-bark#n=3

Thanks!!! I am fertilizing at every watering with a high nitrogen solution at 1/4 of the strenght. Some of my pots are completely dry in 4-5 days. Its fine to fertilize this much?

Yes, that's fine. 1/4 strength every 4 or 5 days is no problem. I don't grow the same plants that you do, but here in SE Georgia, my containers can dry out almost every day in the summer with heavy drinking plants. I fertilize with almost every watering, almost every day. I soak the container with regular water, then put some fertilized water on top, so it quickly disperses throughout the pot. I use almost full strength fertilizer, but I don't put too much on, so it probably equals out to 1/4 strength spread through the pot.

Thanks! ! ! Thats a relief, I am fertilizing some plants almost daily too. And we are in autumn here haha!