What Is Orchid Fertilizer?

Fertilizer Ratio

• Orchids require fertilizers that are rich in nitrogen. Most orchid fertilizers available at gardening stores will already have a high nitrogen content, but gardeners may need to buy a general fertilizer and assess the nitrogen levels with orchids in mind. All fertilizers have three numbers, such as 10-18-10, which stand for the percentage by volume of nitrogen, phosphorous and potassium, respectively, in the fertilizer. Because orchids live in soil that provides little nitrogen, they need fertilizers with a higher nitrogen ratio, such as 30-10-10.

Dilution

• Because orchids are prone to root burn from excessive, strong fertilizer applications, gardeners need to dilute the fertilizer before applying. Fertilizers that are specifically designed for orchids are sometimes already diluted, but gardeners frequently need to do this work themselves. Adding water to a water-soluble fertilizer is all it takes. Gardeners should dilute it to one-quarter strength.

Timing

• Though orchid fertilizer is already weak, orchids need little of it to thrive. A weekly application of weak fertilizer is plenty, and even once or twice a month suffices for many orchids, according to the University of Hawaii. Gardeners should completely refrain from fertilizing orchids during the dormant season.

Flowering Rates

• Fertilizer's main job is to sustain orchids' life and encourage flowering. This means that reducing fertilizer applications will not harm most orchids, but it may prevent them from blooming. To give orchids an extra blooming burst, gardeners can temporarily switch to a high phosphorous fertilizer -- such as 10-30-20 -- in the fall.