Marianne's Response

How Much Plant Food Is Needed for Different Sized Pots?

Please advise rates of application (dry measure) for standard 4 thru 12 inch flower and vegetable pots of 17-5-11.

Posted by Woody Wehr on February 24, 2017

Marianne's Response

Tough question because there are no "standard" pot sizes. We are mostly familiar with Osmocote Plant Food since that is a high-quality dry plant food. It comes in two formulas, 15-9-12 for annuals and container plants and 14-14-14 for beds with perennials and vegetables. I don't know the formula in the question but would think the 15-9-12 application rates would be essentially the same as for the 17-5-11 product. Speaking generally, a 4-inch pot holds 1 pint of potting soil, a 5 to 6-inch pot holds 1 quart, a 7 to 8-inch pot holds 1 gallon, an 8.5-inch pot holds 2 gallons, a 10-inch pot holds 3 gallons and a 12-inch pot holds 5 gallons in the same order as above, the approximate amount of 15-9-12 Osmocote to use is 1/2 teaspoon/pint, 1 teaspoon/quart, 1.5 tablespoons/gallon, 3 tablespoons/2 gallons, 4.5 tablespoons/3 gallons, and 8 tablespoons/5 gallons. The caps on Osmocote 1 and 2 lb. bottles hold 3 tablespoons. Keep on growing!