Honestly I just use any 20-20-20 fertilizer that is good quality, and I dilute 2x more than whatever the package says.

Here is a link that might be useful: African Violets

I've never used Jack's before. Optimara, I've not a lot of success with honestly.

I've just started trying something different with using organic additives to the soil to feed the plants. This is a trial thing, and my conclusions has not been reached because I'm still observing the results.

What kind of organic additives are you experimenting with and how long is your trail so for?

I have never used Jack's but have had success with Optimara. I've just started using Miracle Grow 20-20-20 about 1/8 tsp to the gallon. The urea content is not too high with this fertilizer, so I will see how it does. I may eventually step up to 1/4 tsp per gallon if all goes well.

I have never used Jack's but have had success with Optimara. I've just started using Miracle Grow 20-20-20 about 1/8 tsp to the gallon. The urea content is not too high with this fertilizer, so I will see how it does. I may eventually step up to 1/4 tsp per gallon if all goes well.

I started back in June. First I started off with the basic bone meal, blood meal, and something else that I can't seem to remember at the moment.

Now I'm also testing a product called flower-tone which seems to yielding more flowering success.

I've also been experimenting with using diatomaceous earth in the potting mix to ward off some critters which seems to be working as well.

I've used Optimara for a long time and have had great results with it. I use 1/8tsp per gallon on both my AVs and all my other gesneriads. The only exception is Streptocarpus saxorum. It requires very little in the way of fertilization and only receives this amount of fertilizer every 4th watering. I wick water all plants that aren't in hanging baskets.

I use orchid food and currently Jack's 20-20-20 at HALF rate.

NO UREA!

If you look at the Jack's or Miracle grow fertilizer - it supplies most of it's Nitrogene in a form of Urea - and this is a cheapest source. They changed the formula to save the costs. Urea should be only used on outside plants, because soil - dirt- loam - whatever is on a surface of Mother Earth has bacteria that converts urea to the form it can be used by green plants. The only plant that can take urea is a single cell algae - the stuff that make the old puddles of water green.

There are not many but some fertilizers that do not have urea - Optimara sells a very good stuff - not cheap if you have a large collection, DynaGro is excellent - you need to use 1/4 of a teaspoon, not 1/8 per gallon, Plant Marvel has 2 no-urea formulas, you can order it from their site.
It is good to add an equal amount of Epsom salt every so often to green up the plants.

I was using Peters African Violet Specialty Fertilizer for years - and they recently changed the formula - and use urea too...

I.

Irina that is very interesting about the epsom salt. I have never heard that before.

Epsom salt is a magnesium sulphate - strong salt laxative and good stuff to soak your feet after a tiring day - sells in a pharmacy.

It is also helps plants to build chlorophylle - greening the leaves and jump starting photosynthesis.

Good to dump a quarter of a cup under each rose in a garden in a spring.

I used to swear by Volkmann Bros. fertilizer, but it is unavailable now. I use Jack's 20-20-20, with added Orchid fertilizer as many of my plants are varigates and I needed to "green them up" a bit. I also use a little Superthrive with my plants. I tried the epsom salts, with no noticible difference. My plants really like this mixture.