When it comes to feeding my plants, I use a balanced, all-purpose fertilizer for the most part. My favorite is Jack’s Classic All Purpose 20-20-20 fertilizer. I began using it 5 years ago when I started growing roses and I’ve been loyal to it ever since. I like that it’s got a 20-20-20 NPK value so I can give it to my heavy-feeding roses at full strength, and then dilute it down to a weaker solution for my smaller plants.
However, sometimes I want to use specialty fertilizer for a couple plants that require a fertilizer with a different NPK ratio, such as my white and red frangipanis. Because I only have two small plants that require this type of feed, I don’t want to mix up a large batch of Hawaiian Bud & Bloom 5-50-17 fertilizer. Instead I use a smaller watering can, so of course I need to change the amount of fertilizer I add to the can.
If the original formula is 1 level tablespoon per gallon of water, how do I calculate the amount of fertilizer for a 1000 mL watering can?
The easiest way is to use a Recipe Converter. Yeah, you know, one of those online tools that will calculate the ingredients in your recipe if you want to increase or decrease the servings?
Sure, you can bust out a calculator, some paper and a pencil to do all the math manually. But when there’s a tool (several in fact) out there that already calculates the formula for you at the click of a button, why bother?
You do need to know the size of the smaller container you’re converting to. In my case, the container was already graduated in milliliters so all I needed to do was find out how many milliliters were in 1 gallon (the original formula). In order for the formula to work, all your measurements need to be in the same unit. A quick Google search told me that there were 3785 milliliters in 1 gallon.
Using the recipe converter, I filled in the following information:
- Original Servings: 3785
- Needs to Serve: 1000
- Ingredient: 1 Tablespoon fertilizer
After converting, it gave me 0.75 Tablespoons of fertilizer for 1000 milliliters. Super easy!
