Hi Jonna, I was wondering whether you ended up with a solution or workable suggestion for your wanting to foliar feed your, was it, pothos, or plants in your pond box?
I used to use a Seaweed plant food that is a 0-0-1 formula (the one percent being soluble potash) that is a "liquid concentrate made from freshly harvested seaweed". It is suggested that when diluted with water it would be "most effectively used as a foliar spray that would be fast acting and make nutrients immed. available to the plant". (This is what the label on bottle says.) In the past I had used this recommended product as a foliar spray to help strengthen the leaves of my outdoor succulents in preparation for the high desert winters. If you are interested I can tree mail you the brand and product name and you can find its availability on the Internet.
Bev