Talking Plants

Jillian Patrie | University of Minnesota Yard and Garden Extension

Fertilizing houseplants is important to maintain healthy and happy plants, but how much and when is a common question houseplant owners ask all the time.  Fertilizing schedules will depend on the houseplant and the season, so let’s talk about a few ways to fertilize your houseplants properly.
Houseplant variety can determine when and how much and what kinds of fertilizer are used.  For example, African Violets will bloom all year and generally don’t take much of a break, so fertilizing them regularly is recommended.  Holiday cactus will only bloom in the winter months as their cycle is connected to day length and temperature. Cacti, succulents and sansevieria may not receive water for months and determining how and when to fertilize them can be unclear.
During the winter months many houseplants are growing slowly due to the lack of light intensity and length.  Fertilization can occur during this time, however keeping it to a minimum is suggested, about half the amount and frequency as is done in the spring and summer.  When plants are fertilized, they will push out more leaves and roots, but the new growth can become leggy.  This is not true for all plants, and if you are using supplemental lighting, plants may not slow down their growth at all during the winter.  Fertilizing plants at the same time as watering is a common practice and during the winter many plants slow their growth and water uptake, resulting in a decrease in watering needs.  However, if you are still watering your plants the same as during the summer, cutting the frequency of fertilizing by half is recommended.
There are a few houseplants that bloom during the winter months, so fertilizing is key to keeping them healthy.  Holiday cacti will bloom from November until April, when the day length is short, and home temperatures are usually cooler.  Fertilize your holiday cactus monthly from June to August at half strength with a balanced fertilizer.  Once blooming begins in the fall, change to a low Nitrogen and high phosphorus fertilizer. https://extension.umn.edu/houseplants/holiday-cacti.
More information can be found at https://extension.umn.edu/managing-soil-and-nutrients/fertilizing-and-watering-container-plants.

For questions about this article or local assistance please contact Clay County Extension Educator Jill Patrie at 218-299-7338 or patri350@umn.edu.