There are a number of different cacti and succulent fertilisers on the market, and many different growers will have their own favourites, but I have had very good results by using a standard Tomato feed fertiliser at half strength, I personally like to use Maxicrop organic tomato fertiliser with added seaweed extract, and I have noticed a massive difference in their flowering as well as their overall health, and I haven’t had any cacti or succulents produce any tomatoes yet haha! this product is 100 free from animal ingredients which is important for me as a Vegan.
Here is a link to purchase Maxicrop organic tomato fertiliser: goo.gl/nCwr93
I use the tomato feed at half strength to the recommended dose on the bottle for tomatoes and use it with every third watering that I give to the cacti and most of the succulents during the Spring and Summer. Other than some of the Autumn and Winter growing succulents, I stop feeding the cacti and succulents altogether from early September until early March.
I also like to use Maxicrop organic houseplant and flower fertiliser on my other houseplants and like to use the Maxicrop organic range because they do not use any animal products in their organic range of fertilisers, this is important for me as a Vegan.
Here is a link to purchase Maxicrop Flower and Houseplant fertilser : http://goo.gl/CQo8yJ
Here is a video below that I have made for my You Tube channel on How I fertilise my Cacti and Succulents :