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How to Choose the Right Fertilizer for Your Orchid

August 8, 2012

fertilizing phalaenopsis orchidsOrchid-growing experts recommend fertilizing Phalaenopsis amabilis orchids every other week or at least once a month. As discussed in our previous post, fertilizers provide beneficial nutrients that promote healthy orchid growth. Botanists have identified 17 nutrients essential to optimal orchid development. Three macro-nutrients—nitrogen (N), phosphorus (P) and potassium (K)—are considered critical; but micro-nutrients (also called “trace elements”) also play an important role in the health of Phalaenopsis orchids.

Essential Nutrients and Their Uses

Calcium, iron, copper, zinc and other micro-nutrients strengthen new stem and flower growth so stems are strong enough to support the weight of multiple blooms and blooms do not droop. Unlike terrestrial orchids that obtain important micro-nutrients directly from the soil, tree-dwelling epiphyte orchids, such as Phalaenopsis orchids, must rely on fertilizers to supply their nutrient needs.

Choosing a Fertilizer

For Phalaenopsis orchids, choose a complete, balanced orchid or all-purpose flower fertilizer that contains equal amounts of nitrogen, phosphorus and potassium (look for 10-10-10 or 20-20-20 on the label) plus micro-nutrients. Choose a non-urea fertilizer as this nitrogen component can take up to a year to break down and be available to the plant. In non-urea fertilizers, 100% of the nitrogen is immediately available to the orchid.

To fertilize your Phalaenopsis orchid, mix the recommended amount of fertilizer at half strength. Making certain drainage holes are unobstructed, place your orchid in the sink and pour fertilizer into the pot until liquid runs out the bottom. Allow to drain before returning your orchid to its decorative container. Do not water your orchid with ice on the weeks you fertilize it.

For more information on orchid fertilizing, see "Trigger Orchid Re-Blooming" on our website.