The numbers 10-10-10 refer respectively to the percentages of nitrogen, phosphorus, and potassium in synthetic fertilizer. Though considered all-purpose, 10-10-10 fertilizer is generally better for non-fruiting plants due to its high nitrogen, which stimulates leaf growth. It’s a synthetic fertilizer that works especially well on perennials and plants grown for their foliage. However, it’s also good for established fruiting perennials, such as strawberries. The nitrogen in 10-10-10 fertilizer can help lawns grow denser and greener. Apply it at a rate of 1 pound per 1,000 square feet. This is a slow-release formula so it’ll feed your lawn continuously, giving you more time before your next application.