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How to diagnose—and heal!—sad, sick plants

Urban flower farmer Sarah Nixon from My Luscious Backyard shares her advice on how to cure common plant ailments — from pests and overwatering to powdery mildew.
By Sarah Nixon
How to diagnose—and heal!—sad, sick plants

5 common plant problems and how to fix them


The signs: Lower leaves that are yellow and dry, slow growth and poor flowering or fruiting.

How to fix: As a general rule, sandy soil will need more water than clay soil. Watering thoroughly and less often is better than lightly and frequently. Use a hose wand instead of a sprinkler to adequately water each plant. 

How to diagnose—and heal!—sad, sick plants

Japanese Beetles

The sign: Metallic green bugs munching on leaves, buds and flowers.

How to fix: Regularly hand-pick beetles off plants and drop them in a bucket of soapy water. Introduce roundworms to the surrounding soil — they’ll happily eat the beetle larvae.  

How to diagnose—and heal!—sad, sick plants

Powdery Mildew

The sign: White spots on the tops and bottoms of leaves and stems. 

How to fix: Prevention is best. Mix 5 mL baking soda and 10 mL horticultural oil per litre of water. Spray plants every week or two before mildew season (mid to late summer). 

How to diagnose—and heal!—sad, sick plants


The signs: Aphids are small soft shelled insects which come in many colours, most commonly green, black, brown, white or yellow. They suck the sap from plants and can usually be found on the undersides of leaves. 

How to fix: Spray the entire plant, especially under leaves with a mixture of 40 parts water and one part liquid soap (not dish detergent). Leave on for 10 minutes then rinse thoroughly with water. Repeat three times, three days apart.

How to diagnose—and heal!—sad, sick plants

Lack of sunlight

The signs: Length of stem between leaves (the internodes) is stretched. Leaves may be paler green or smaller than usual with few flowers.

How to fix it: Move to a brighter spot or prune plants around it that are casting shade. Even shade-loving plants need at least three hours of direct morning sun each day.

How to diagnose—and heal!—sad, sick plants

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