Houseplant Health Care Basics

Robert Mugaas
University of Minnesota Extension Educator, Horticulture

Even though many of our favorite indoor plants originate in tropical areas of the world, most are fairly adaptable to indoor environments. Houseplants provide living spaces with greenery and other colors, and opportunities to learn about plant care and growth. A study performed by NASA and the Associated Landscape Contractors of America during the late 1980s, concluded that common houseplants also help to purify the air by removing harmful elements such as trichloroethylene, benzene, and formaldehyde.

Whether you have a green thumb or not, a houseplant can be easy to care for with a bit of attention and care. Following are some basic guidelines for success with houseplants.

Light

  •  Light is usually the most limiting factor when it comes to keeping indoor plants healthy. Remember, all plants need light to grow and thrive. Weak stems, undersized and poorly colored leaves, and spindly growth are good indicators that plants are suffering from a lack of light.
  •  Before purchasing plants, take a little time to note where the sunny and dark locations are in your home. This will help guide your plant purchases relative to the amount of suitable space you actually have to grow plants.
  •  Most indoor plants, even those adapted to darker conditions in the home, will be healthier if they receive an hour or two of direct sunlight each day, so long as it is not too hot.

Water

  •  Knowing when and how much water to apply can sometimes be confusing. Remember, the amount of water required will vary dramatically among many different indoor plants. Managing water needs is almost always easier when plants are growing in pots with drainage holes in the bottom, rather than in those without drainage holes.
  •  When watering your plants, apply enough water such that it runs out of the pot’s drainage holes. With most houseplants, allow the top ¼ to ½ inch of soil to dry before watering. Learn to water based on soil conditions and plant needs rather than on a fixed schedule. For convenience, you may want to group plants with like watering requirements together rather than having them scattered individually all over the house.

Temperature

  •  Different houseplants will have varying requirements for optimal temperature. In general, plants prefer warm days with slightly cooler night temperatures.
  •  Keep houseplants out of cold, drafty locations, such as doorways in the winter or air conditioning vents during the summer. Likewise, hot, dry spots should be avoided, such as heating units or hot air vents.

Humidity

  •  Our homes become quite dry over the course of the fall and winter heating season. As a result, indoor plants often languish in these very arid, low-humidity conditions. Artificially increasing humidity around plants will discourage damaging spider mites and other insects that thrive in warmer, drier conditions.
  •  Misting plants is not a particularly good way of raising humidity. Even though humidity levels are temporarily raised this can be a good way to encourage the growth of foliage diseases. A better way to raise humidity is through the use of a room humidifier and by grouping plants a little closer together where the water vapor they give off helps raise humidity levels.
  •  Plants can also be set on shallow trays of pebbles where water has been added just below the surface of the pebbles. As the water evaporates from the tray, it raises the humidity around the plants. However, always be sure that the bottom of the pot is never sitting directly in the water, as this can result in the untimely death of your plant.

Providing Nutrients

  •  Plan to fertilize plants only during those times when they are actively growing. Usually this will mean during late winter, early spring, and through the longer days of summer.
  •  Fertilizing during periods of inactive growth or “resting” periods is usually unnecessary and may even be damaging. However, where plants grow under lights, they may be actively growing most of the time, such that fertilizing may need to be more frequent.
  •  There are many types of houseplant fertilizers on the market, both organic and inorganic. Almost any will do provided you adapt the label recommendations for use to the time of year and the plant’s needs.
  •  Organic fertilizers can be used at recommended label rates while inorganic sources should be used at about half the recommended rate. Avoid excess application of any fertilizer as this can cause browning of leaf margins and tips as well as “burn” tender plant roots. It may even kill the plant. Never fertilize a plant in dry soil. Rather, water the plant thoroughly first, then follow-up with a second watering that contains the fertilizer.

Cleaning Plants

  •  Washing the foliage in warm, slightly sudsy water followed by a clean water rinse removes dust from the foliage and may even help prevent some potential insect or disease problems. A couple drops of dishwashing soap in a quart of water makes a satisfactory “cleaning solution” for many of our green foliage plants. Keeping the foliage clean may even make the difference as to whether or not some plants will bloom.
  •  Varying environmental conditions such as light, heat and humidity will also affect our plant’s water needs. For example, a well-lit plant will require more frequent watering than one growing in minimal light.

Simple Houseplant Care Tips

Success with growing plants indoors is a matter of creating conditions most similar to where the plants originated in the world. Three easy steps to take are:

1. Note the various light levels coming into your home and choose plants adapted to those conditions.

2. Learn to water plants based on soil conditions and plant needs rather than on a fixed schedule.

3. Group plants with similar cultural requirements together. This facilitates being able to care for them conveniently.


Making Plant Containers

There are dozens of pots to choose from at local co-ops or garden centers: terra cotta in all sizes, metal buckets, ceramic in bright colors, and wicker baskets lined with plastic. An alternative to purchasing new pots is finding creative ways to use containers you already have! Plastic milk jugs can be cut down to size to line a holiday basket, or as one plant grows out of a smaller clay pot, propagate your new plants in the smaller pot. Wooden boxes, metal coffee pots, and large decorative tins can hold plants very well. Look around your garage, basement and attic for ideas.

Below are some guidelines for houseplant containers:

  • Make sure all containers are scrubbed clean and are free of rust.
  • Each container must have one or more drainage holes in the bottom. If you’re using a metal container, punch holes with a hole punch or tin snip. Any other kind of material can be carefully drilled with a small drill bit that is suitable for that material.
  • Containers with drainage holes should have water-catch trays placed beneath them. Plastic or ceramic plates and trays are simple items that can catch excess water as it drains away.
  • Decorating plain household items is a good way to include children in household plant care. Gather up watercolor paints, extra pieces of fabric and glue, and give children free creative reign to make lovely homes for your household plants.
Houseplant Health

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