How to use fertilizer?

Question

I have a sack of Agway 10-20-20 fertilizer in my basement. I believe it is a granular fertilizer. It is pellet like. I know the 10-20-20 is the NPK ratio. I am wondering, though, how i actually use fertilizer like this? How much per X. amount of soil? Toss on top of soil or dissolve in water? I have not a clue. I plan on using on potted house plants. WHAT SHALL I DO??

Answer 1

That type of fertilizer is designed to be used more for outdoor gardens than houseplants. The NPK ratio shows that it is for enhancing fruiting and blooms more than green growth. It is to be spread on top of the soil and watering/rain dissolves it over time to let it sink into the soil.

It can be used on house plants, but it will not always act as you might expect. The reason is that the different color pellets you see in the bag are the different components of the fertilizer. Putting them in a small houseplant pot will not distribute the different materials equally, as when they are broadcast into a large garden area. You may end up overdosing your houseplant on N, P or K.

You'd be much better off with a liquid soluble fertilizer (Peeters, Miracle-Gro, etc.) or a time release pellet (Osmocote) designed for your houseplants.

Answer 2

Fertilizer is used at pounds per 100 square feet (or acres).  The ratio is going to depend on the deficiency of the soil (or what soil conditions your are trying to achieve).  10-20-20 is a general purpose fertilizer, but I (personally) would be hesitant to use it in small containers- it is very easy to get too much.  Remember, fertilizer is a type of salt- too much will burn (and kill) your plants.  It’s just my too cents, but in a pot or container, I would use something with a little more “wiggle room” like Miracle Grow.  If you do use it on the house plants, I would use a couple tablespoons on top of the soil and water it in.  

-K