Gardening Help FAQs

Here are answers to some of the most common questions we receive about garden plants. You will find concise information on general gardening techniques as well as plant selection and care. For detailed information on specific plant pests and problems refer to our Common Garden Pests and Problems page.

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Horticulture Questions and Answers

Why does my indoor plant have leaves with brown tips?

The browning of tips and/or margins of the leaves of indoor plants usually indicates unresolved stress due to mechanical injury, unfavorable environmental conditions, or toxicities and their interactions. Such plant stresses may arise from any one, or a combination, of the following factors: low humidity, excessive fertilizer or other soluble salts, poor water quality, unfavorable soil pH, overwatering, under watering, physical injury, pesticides, or direct sunlight. A likely consequence of uncontrolled plant stress is attack by disease organisms and/or insects. Let's look at indoor plant environments with the goal to see how stress management can work for us.

The main environmental factors affecting the foliage of indoor plants are light, temperature, and relative humidity.

Plants have a tremendous ability to adjust to varying light conditions, providing that these conditions do not vary widely from day to day. Any changes of indoor locations involving significant changes in plant light levels should be made in stages to allow for proper acclimatization. Improper acclimatization may produce symptoms that can be confused with disease or pest attack, such as leaf drop, leaf tip browning, and the like.

The effects of temperature on indoor plants are easier to deal with than those of light. Since most indoor plants are tropicals, they generally benefit from warmer daytime temperatures and somewhat cooler night temperature; however, as a general rule the latter should not be allowed to fall below 55F. Many health management problems occur when indoor plants are placed in drafts of hot or cold air. These are to be avoided in all seasons. Watering indoor plants with very cold water can also lead to difficulties with foliage and flowers. Large fluctuations in ambient temperatures, such as caused by turning off air conditioning, are detrimental and should be avoided.

The low relative humidities often experienced in our homes during winter months can cause problems with the foliage of many indoor species. This can be especially noticeable in cases where plants are exposed to direct sunlight; leaves will dry out due to overheating and often turn brown, (scorching), or yellow. Such conditions may reinforce the difficulties stemming from those which may occur to faulty watering practices, especially those seen when plants are too dry. These situations are very favorable for the rapid development of populations of spider mites. Use misting, mist generators, and pebble water trays to improve relative humidities around your plants.

The environment of the root system of a specific plant is a key factor in managing the health of that plant. The first item to consider is soil. Potting media must have good stability and resistance to compaction, and must provide good drainage. Generally a pH in the range of 6.0-6.5 will be optimum for uptake of essential nutrients. Plants indoors, especially those under low light conditions, need low levels of fertilization. To avoid accumulation of salts, from water, fertilizers, and soil, leaching should be incorporated into your watering program. At each watering, some water should drain from the pot, and, after a 10-15 minute drain time, be discarded. Water should never be allowed to be reabsorbed by the medium. This will surely lead to foliage problems, and/or root rots. Also remember that indoor plants which are excessively dry can be damaged by soluble salt concentrations, and this condition can lead to explosive spider mite population increases as well.

All of these can lead to foliage damage like browning, yellowing, or leaf drop. Learn to recognize such symptoms early, make correlations with environmental conditions, and take corrective steps at the earliest possible time.