Planted Tank Guru
Join Date: Jan 2010
Location: Contra Costa CA
Yes. Ferts sold for aquarium use can be used on garden or house plants.
To figure out the dosing is a bit tricky, but just dose very lightly and it will be fine.
Here are two ways to figure out dosing:
1) Find a product intended for the plants you have in mind, in liquid form, and compare the N, P, K or Fe. Whichever is highest, use that and do some math.
example: lets say you find a house plant fertilizer that is 5-10-5.
And you want to figure out how to use Seachem Flourish Nitrogen. Per label, this is 1%N and 2%K
Use the potassium, since that is highest. Comparing the potassium in the house plant fertilizer (5%) to the Seachem Flourish Nitrogen (2%) you can see that you would dose the Seachem product a 2.5x the dose of the house plant fertilizer.
2) More complex is to figure out how much actual N, P, K or Fe is in the product, and compare the dosing to any other fertilizer that is labeled for your plants. Ferts are labeled as % active ingredient by weight.