How often should orchids be fertilized?
Written by
Kiana Okafor
Reviewed by
Prof. Samuel Fitzgerald, Ph.D.The frequency of fertilization can have a direct effect on the health of orchids, which requires careful seasonal adjustments. I killed my first dendrobium by fertilizing it throughout the entire year, before I understood that orchids require a period of rest. The growth cycles of orchids govern their fertilizer schedules. In more active phases, they need more nutrients. When they revert to dormancy, resting phases, no fertilizer should be provided while they recover.
Spring Schedule
- Weekly applications at quarter strength
- Begin when temperatures exceed 60°F
- Focus on balanced formulas with calcium
- Support new leaf and root development
Summer Adjustments
- Maintain weekly frequency but reduce nitrogen
- Pause applications above 85°F
- Increase potassium for heat resistance
- Water roots before fertilizing to prevent burn
Fall Transition
- Shift to biweekly applications
- Lower nitrogen as growth slows
- Emphasize phosphorus for root hardening
- Prepare plants for winter dormancy
Winter care is very different. Tropical orchids such as Phalaenopsis should be fed each month at quarter-strength. Temperate varieties should have feeding completely stopped if the temperatures drop. I made the mistake of feeding dendrobiums during their dormancy period, which subsequently caused the roots to rot. Feed visually, according to growth signs, not by the calendar.
During the active growth phases, use the weekly weakly method of fertilizing. Dilute your fertilizer to one-quarter of its original strength and apply it weekly, rather than using full strength once a month. This will allow the fertilizer to slowly seep through the media, preventing the build-up of salt while providing a slow release of nutrients within the press. I prefer this method for all my epiphytic orchids starting in March and continuing until October with great success.
Watch your orchids for signs of timing. New root tips indicate feeding time, plump pseudobulbs signify they are ready, and flower spikes require phosphorus. I document how each responds and adjust each plant's feeding schedule accordingly. Your ability to observe and react will produce far healthier orchids than any schedule will achieve.
Adjust for any special conditions. After repotting, wait four weeks before resuming feeding again. In the summer, pause feeding if the temperature is above 90°F during a heatwave. For stressed-out plants, reduce the frequency to half until they recover. These adjustments allow for the prevention of over-fertilization, plus, your orchids will still thrive all year round and bloom to their best potential.
Read the full article: How to Fertilize Orchids: Ultimate Guide
