How to Choose the Best Orchid Fertilizer, According to an Expert

Orchids are more susceptible to over-feeding, which is why purchasing the correct formula is key.

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Tropical orchids are epiphytic, which means they grow out of soil on the surfaces of other plants in their natural habitats. Because of this, orchids function differently than other varieties and have much more specific needs. This means that you can't use any old fertilizer when you want to give your pretty orchids a boost. Ahead, discover everything you need to know about feeding this houseplant, including some of our favorite formulas to try.

Ellie Miller

Nitrate-Rich Formulas

Orchid fertilizers are often made with more nitrates than ammoniacal nitrogen, notes Renata Goossen, a consumer specialist at Just Add Ice Orchids. "While orchids can take in all forms of nitrogen found in fertilizers (like nitrate, ammonia, and urea), they prefer the nitrate form of nitrogen for long-term health," she says. "A study published in HortTechnology found that supplying a higher ratio of nitrate to ammoniacal nitrogen allows for larger flowers and better calcium and magnesium uptake."

Identifying a Strong Orchid Fertilizer

Goossen says there are a few factors to consider when shopping for orchid fertilizers, like the aforementioned nitrate to ammoniacal nitrogen ratio. "It's important to have both forms, but focus on finding a fertilizer with higher nitrates," she says. As for the ingredient ratios to look for? "A robust fertilizer, such as 13-3-15 (like the MSU Orchid Fertilizer 13-3-15 ($10.99, can be applied twice monthly and will do the trick," she says. "This is better than applying an extremely low-rate fertilizer every time you water." Feeding your orchids too often, she says, will lead to salt build-up, which can cause fertilizer burn. "By alternating between fertilizer water and clear water, you can flush excess salts." Lastly, she suggests opting for a liquid option, such as the J R Peters Inc Jacks Classic Liquid Orchid Food 7-5-6 ($15.43, "Liquids are the most thorough and effective form of fertilizer when it comes to phalaenopsis orchids," she affirms. Another one of Goossen's favorites? The Dyna-Gro ORC-008 7-8-6 Fertilizer ($9.49,, which is orchid specific.

Feeding Tips

Once you've purchased a fertilizer for your orchid, Goossen suggests applying it when the plant is in its vegetative, non-flowering cycle. The reason? This is when the plant is producing new leaves, roots, and unopened buds. "You can cut fertilizing out of your routine when the plant is in open bloom and no longer producing buds," she says. "No fertilizer can trigger flower production in orchids, no matter what the bottle says." Instead, fertilizer can fuel orchid health to encourage blooming in future—but it is not responsible for initiating flower spikes. "Most tropical orchid species are triggered to flower by a change in temperature," she explains. "For the phalaenopsis, that is a five- to 10-degree temperature drop at night." To encourage your orchid to bloom, she suggests placing it on a windowsill during the winter months.

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