Question: How can I tell if my houseplant needs to be repotted? What symptoms do I look for? How should I repot my houseplant?
When the weather turns colder and outside garden cleanup is completed, many gardeners focus their attention to indoor houseplants. They are a great way to add color and interest to any room. In addition, there is an increasing body of research indicating that houseplants can improve air quality and maintain healthy, comfortable humidity levels indoors, reduce stress and anxiety, and improve your mental and emotional health. According to the Environmental Protection Agency, average Americans spend 90% of their life indoors. This fact certainly underlines the importance of any improvements to the quality of our indoor environment. Houseplants can definitely enhance our indoor spaces and overall sense of well being.
Growth Habits of Houseplants
To be successful at growing indoor plants, you’ll need to know a lot more than how to repot your houseplants. Let’s review the factors that influence plant growth and how to keep your houseplants thriving.Keep in mind that houseplants are typically tropical or subtropical plants and require different care from plants that grow outside in other climates.
- Light: The most essential factor for indoor plant growth. It is the source of the energy the plant uses to produce the food necessary for its health. Depending on its light requirements, your indoor plant may need to be placed near a southern facing window (for the most intense bright light), a northern exposure (for low light needs), eastern or western exposure (moderate light intensity) or have additional incandescent, fluorescent or LED lighting.
- Temperature: The second most important factor affecting houseplant growth. Indoor foliage plants thrive between 70F-80F during the day and 60F-68F at night. Flowering plants have the same daytime temperature preference but favor 55F to 60F at night.
- Relative humidity: The amount of moisture in the air should be between 50-75 percent, which is often difficult to achieve in a home setting. The average home’s humidity is between 30-40 percent. Find techniques to increase humidity in your home HERE.
- Water: Needs vary depending on the type of plant, growing medium and indoor environment. Over- or underwatering causes a large percentage of houseplants’ failure to thrive. To determine when to water, stick your index finger two inches into the soil. If the soil feels moist, don’t water. Continue to test until the soil is barely moist two inches deep and then use this watering technique.
- Fertilizer: Should be applied according to the directions on the label of the commercial fertilizer used. The frequency of application depends on the needs of the specific houseplant. Many plants require fertilization every two weeks from May to September. During the winter, fertilizer is not usually needed because less light and lower temperatures result in less plant growth.
- Soil: The soil or growing media anchors the plant in the pot, and holds water, minerals and other nutrients. Use a professional potting mix or mix your own. Note that some houseplants (orchids, bromeliads and African violets) require special mixes.
- Ventilation: Houseplants, especially flowering plants, are susceptible to drafts, forced air from heating and air conditioning systems, or natural or blended gases. Plants may wilt, drop flower buds or foliage as a result. Keep indoor plants away from forced air flows.
When Your Houseplant Needs Repotting
The time to repot depends on how fast your plant is growing. It’s time to repot when the plant:
— Is pot or root bound (roots fill the pot and grow out of the drainage holes).
— Shows limited or no growth, foliage is discolored and/or emerging new leaves are small, and thin. In most cases, this is due to reduced nutrition and compacted soil
— Wilts within a day or two of watering.
— Appears top-heavy when compared to the size of the pot.
Note that while most house plants will benefit from repotting at the right time, certain species actually prefer to be pot-bound, such as African violets, aloe and jade plants.
How to Repot Indoor Plants
There is seldom need to repot plants when you bring them home from the garden center. Monitor the plant’s growth, care for it appropriately and when it shows symptoms of needing repotting:
- Pick a pot (typically plastic, clay, ceramic or fiberglass) that is one-third larger than the old pot. Be sure the new pot has a drainage hole. If reusing a pot, be sure to clean and sterilize it in a 10 percent bleach solution prior to repotting.
- Select a commerical or homemade potting mix or potting soil designed for indoor plants. A soilless blend of three parts sphagnum moss, one part vermiculite and one part perlite is a good choice for most houseplants. Do not use garden soil unless it is sterilized first.
- Water the plant in its orginial pot and let it sit for an hour.
- Before repotting, trim off any diseased part of the plant and consider pruning carefully to adjust the size and shape of the plant.
- Gently remove the plant from the old pot. It should come out easily. Spread the roots out so they no longer form a dense mat or circle around the root ball. Make three to four vertical cuts one inch each deep in the root ball.
- Place enough pre-moistened potting mix in the pot so the top of the root ball will be slightly above the desired height (one to two inches from the top of the pot). This leaves room for watering and plant growth. Tap the potting mix down gently to avoid root damage and soil compaction.
- Water the pot so the mix will settle to the desired height.
- Center the plant in the middle of the new pot, fill with mix between the root ball and the pot.
- Move the pot to a location that suits that plant’s specific growth requirements.
More on Houseplants
Eager to learn more about indoor plants? Expand your collection with easily maintained and durable houseplants like the snake plant (Sansevieria trifacta), spider plant (Chlorophytum comosum) or heart-leaf philodendron (Philodendron scandens). Research specific characteristics and plant care requirements. Diagnose houseplant problems with this guide and consult the Virigina Cooperative Extension 2021 Pest Management Guide: Home Grounds & Animals for ways to manage plant disease, and common insects and related pests.
Good luck on repotting indoor plants and enjoy them all year long!
Image Sources: Photo 1, Karolina Grabowska; Photo 2, Bogdan Knurly
References
“Caring for Houseplants”, University of Missouri, MU Extension, July 2017.
“Caring for Houseplants”, Kelly, Kathy, PH.D., Professor of Horticultural Marketing and Business Manage, Penn State University, Penn State Extension, 19 Oct. 2007.
“Common Houseplant Insects & Related Pests”, Clemson University, Clemson Cooperative Extension, Home and Garden Information Center, 10, Sep. 2021.
“Easy Houseplants”, Perry, Dr. Leonard, Extension Professor, University of Vermont Extension, Department of Plant and Soil Science.
“Growing Indoor Plants With Success”, University of Georgia Extension, Bulletin 1318, 27 May 2020.
“Indoor Plant Culture”, Alex X Niemiera, Professor, School of Plant and Environmental Sciences, Virginia Tech, Virginia Cooperative Extension, Publication 426-100, 6 Nov 2018.
“Fertilizing Houseplants”, Pettinelli, Dawn, Manager, University of Connecticut, College of Agriculture and Natural Resources, Cooperative Extension,CpSoil Nutrient Analysis Laboratory.
“Preventing, Diagnosing, and Correcting Common Houseplant Problems”, Kelly, Kathy, PH.D., Professor of Horticultural Marketing and Business Manage, Penn State University, PennState Extension, Department of Horticulture Fact Sheet, 27 June 2016.
“Repotting Houseplants”, Kelly, Kathy, PH.D., Professor of Horticultural Marketing and Business Management, Penn State Extension, Department of Horticulture Fact Sheet, 23 Oct. 2007.
