A Quick Guide to Diagnosing House Plant Problems
Houseplants are generally easy to grow, but occasionally things go awry. Here are a few tips to understand the problems so you can adjust growing conditions.
Yellowing leaves
When yellow leaves show up, most likely this is a sign that the basic growing conditions are not right for that plant. The plant will get rid of older leaves first. See table below for solutions to the four major reasons for yellowing leaves.
Burnt edges / brown tips
When the edge or tip of a leaf is discolored or burnt, an excess of something is usually the cause, such as too much fertilizer, softened water, or sunlight. Consider collecting rainwater instead of using softened water.
Plants benefit from a drenching every few weeks or months, so give plants an occasional shower. Salts build up in the soil from fertilizers (and softened water) and will eventually burn roots, which in turn shows up as a burnt edges or tips. Plus this shower is an easy way to wash the leaves.
If the burnt area is in the middle of the leaf, this is sunburn. Recognize situations that can cause sunburn, such as moving plants outside for the summer without a transition period or placing plants in direct exposure to south or west sun in winter.
Stickiness
If the floor around your plants becomes sticky or a dried syrup-look is visible on leaves, look on the underside of leaves or along the stems. Most likely the slow-moving, highly camouflaged insect called scale is present.
Stickiness can also be caused by aphids or white flies, but these insects are usually more evident. Scale, and its white cottony cousin mealy bugs, can be quite sneaky and seem invisible until there is a well-established infestation.
Other than disposing of the plant, effectively controlling scale or mealy bugs requires drastic measures with the use of strong pesticides. You will have to decide if the plant is worth the effort.
Yellowing Leaves
Causes: | Solution: |
Not enough light – when a plant doesn’t get enough light, it can’t support all of its foliage, so it sheds the older unproductive leaves. | Provide sufficient light for each plant. Consider pruning to encourage new growth. |
Not enough food – when there is only so much fertilizer to go around, the growing tips will take what they need first. | Feed regularly with a liquid fertilizer. Most indoor plants should be fertilized every two weeks in spring & summer, once a month in fall & winter. |
Too dry – When the soil dries too much, roots die and can’t support the foliage any longer. The result is yellowing of older leaves. | Most plants prefer weekly watering. The soil should be quite dry at the time of watering but not excessively dry. Always water thoroughly. |
Too wet – Roots rot when soil stays too moist. When roots aren’t happy, the plant isn’t happy. | If at the time of watering the soil is still wet, wait another week to water. |