Hummingbird House The Garden Helper
No-dash-here, you've found The Real Garden Helper! Gardening on the Web since 1997
vine bar
Wild Willy
 

Plant Health Problems

Willy the Garden Gnome The majority of the gardening questions I receive pertain to problems and insect pests related to house plants.
Hopefully this page will help to resolve some of these problems!


While many problems are related to insects and disease, most seem to be of an environmental nature, especially in the winter. House plants are all hybrids or species plants which grow wild somewhere in the world. Try to match the environment from where the plant originated from for the best success. You may not be able to match every criteria for the plant, but every step you take towards the plants comfort will be a giant step towards keeping your friend healthy.

Leaf loss or yellowing is often caused by lack of humidity. The majority of houseplants do best with a relative humidity of between 50% and 70%. Plants create a certain amount of humidity themselves through transpiration through their leaves, from the soil, and even their pots if they are porous.
The more plants you have in a room, the higher the humidity will be, and the closer the plants are together the more they will be able to benefit each other. Setting the pots onto a bed of small pebbles and gravel in a shallow tray will allow you to add water to the tray, raising the humidity without giving the plants 'wet feet'. Placing water filled containers around the room will also add considerably to the humidity.
With the exception of fuzzy leaved varieties, houseplants enjoy a daily misting with room temperature water.
Plants need to breathe and enjoy a little fresh air, just as you and I do. It isn't necessary to have constantly changing air, but lightly moving air can often make a difference in the plants growth and health.
A few plants may suffer when they grow in the presence of natural or coal gasses. The effects of gas heat may range from failure to bloom to a complete loss of leaves. Others may just appear to look unhealthy for no apparent reason.
Do you ever talk to your plants? No.... I don't believe that they understand you, but plants breathe CO2 which we exhale, and in turn they exhale oxygen which we need.
I've heard of oxygen bars where you PAY? to breathe canned oxygen. It seems to me to be much more prudent to have a chat with your Philodendron, and give each other a boost!

Plant Problems and the Possible Causes

  • Leaf edges brown and dried:
      Temperature is too high... Move plant to cooler area
      Lack of sufficient humidity... Set plant on a shallow, pebble filled tray of water
  • Browning of leaf tips or on leaf margins:
      Lack of sufficient humidity... Set plant on a shallow, pebble filled tray of water
      Fertilizer burn... Leaching or repotting your plant with fresh soil may be needed
      Poor water quality (chlorine, fluoride, salts, etc.)... Allow water to set for 24 hours before using
      Lack of, or incorrect components of fertilizer... Always follow the directions!
      Spray damage from insecticides, oil, leaf-glossing materials... Wash foliage with clean water and a soft cloth
      Incorrect soil pH... Test and adjust soil pH, or repot your plant
        Iron deficiency may result when soil pH is too high (alkaline)
        Magnesium deficiency may result when soil pH is too low (acidic)
      Pollutants in the air... Fumes from gases, chemicals etc.
  • Rapid defoliation:
      Rapid changes in temperature or light... Was plant moved to a new location?
      Overwatering possible... Check for root damage or rot
      Underwatering... Provide enough water to support full foliage
      Exposure to hot or cold drafts
  • Gradual defoliation (lower leaves become yellow and fall):
      Overwatering possible... Check for root damage or rot
      Underwatering... Provide enough water to support full foliage
      Insufficient light... Move plant to a brighter location
      Lack of, or incorrect components of fertilizer
  • Leaves drop continuously or new leaves on tip are small and curled:
      Pollutants in the air... (fumes from gases, chemicals etc.)
      Spray or vapor damage from cleaning fluids
      Possibly aphid or mite damage
  • Spotted foliage:
      Overwatering possible... Check for root damage or rot
      Sunburn... Too much direct sun
      Cold water on foliage... Use room temperature water for watering or misting
      Fungal infection... Especially possible if plants are in very humid, wet conditions
      Pollutants in the air... Fumes from gases, chemicals etc.
  • Foliage is pale and weak looking:
      Insufficient light... Move plant to a brighter location
      Underwatering... Provide enough water to support full foliage
      Lack of sufficient humidity... Set plant on a shallow, pebble filled tray of water
      Lack of, or incorrect components of fertilizer
  • New foliage is small, pale, and spindly:
      Insufficient light... Move plant to a brighter location
      Lack of, or incorrect components of fertilizer
      Underwatering... Provide enough water to support full foliage
  • Leaves yellowed between veins (veins remain green):
      Incorrect soil pH... Test and adjust soil pH, or repot your plant
        Iron deficiency may result when soil pH is too high (alkaline)
        Magnesium deficiency may result when soil pH is too low (acidic)
  • Failure of plant to flower:
      Insufficient light... Move plant to a brighter location
      Underwatering... Provide enough water to support full foliage
      Fertilizer burn... Leaching or repotting your plant with fresh soil may be needed
  • Flower buds drop before opening:
      Temperature fluctuations
      Exposure to hot or cold drafts
      Lack of sufficient humidity... Set plant on a shallow, pebble filled tray of water
  • Silver or red blotches on foliage:
      Sunburn... Too much direct sun
  • New growth wilted, or burned:
      Fertilizer burn... Leaching or repotting your plant with fresh soil may be needed
      Exposure to hot or cold drafts
      Underwatering... Provide enough water to support full foliage
      Sunburn... Too much direct sun
      Temperature is too high... Move plant to cooler area
      Freeze or frost damage.
  • Entire plant wilted:
      Underwatering... Provide enough water to support full foliage
      Overwatering possible... Check for root damage or rot
      Fertilizer burn... Leaching or repotting your plant with fresh soil may be needed
      Exposure to cold temperatures
  • Stunted plants:
      Fertilizer burn... Leaching or repotting your plant with fresh soil may be needed
      Underwatering... Provide enough water to support full foliage
      Overwatering possible... Check for root damage or rot
  • Tiny white spots on leaves:
      Primarily caused by spider mites.
  • Cotton like masses on leaves and stems (Round or oval shaped bumps covered in cotton):
      Mealy bugs
  • Sticky spots on foliage:
      Primarily caused by aphids
  • Small brown bumps on stems or foliage:
      Scale insects
  • Fuzzy, grey mould that covers flowers, leaves and stems:
      Botrytis blight (A fungal disease generally caused by dead leaves and spent flowers being left on the plant)
      Excess humidity
      Poor ventilation.
  • General drooping of the entire plant:
      Crown, stem or root rot (usually caused by overwatering, especially during the winter months when plants are dormant and do not need much moisture.)
  • Brown or yellow leaf spots:
      Fungi which usually develops when water is allowed to remain on the leaves.
      Cold water can also be a cause of spotting. Use room temperature water for misting and watering, and make sure the foliage dries before night.
  • Mildew:
      Powdery mildew is an airborne fungal disease. (African violets and Begonias are particularly succeptible.)
Good cultural practices will eliminate many diseases and other houseplant problems. If insects and fungal diseases are a problem, visit a reputable nursery to find an appropriate chemical to combat the problem, and ALWAYS read and follow the manufacturers recommendations for that product. Many problems may be halted by removing damaged parts of the plant if they are detected early enough. However vigilance is necessary afterward to make sure that you have completely eliminated the problem.
It is absolutely essential that you always read and follow the product recommendations for fertilizers, or any other garden chemicals.