Solutions: Check the soil or potting medium. Coarse textures can allow water to drain too rapidly, preventing the plant from taking up enough. If the soil and roots seem very dry, add sphagnum moss or other mediums that hold water. Water according to recommendations for each plant's species. Low humidity can be corrected by misting the plant regularly or placing it near a humidifier. Keeping it near other plants helps, too. Keep the environment consistent in terms of temperature, humidity, and lighting. Keep it away from vents, heaters, and air conditioners, and avoid moving it to locations where it will experience a temperature shock. Hot, dry heat, and cold drafts are problematic for many plants. Especially if the plant is outside, it could be experiencing heat or light stress. Try moving it to a shadier location.

Solutions: Bacterial infections need to be treated quickly to prevent the spread to neighboring, healthy plants, potentially wiping out large sections of your indoor or outdoor garden. In mild cases: Use sterilized (10% bleach solution) pruning shears or scissors to remove any infected plant parts, making sure to dispose of them off site. Use a copper-based bactericide to treat the unaffected foliage, as well as the soil, and neighboring plants. Follow the manufacturer’s rate and timing directions found on the product label. In severe cases, where more than half the leaves are affected: Remove all of the infected plants from the garden, disposing of them off site. Treat the soil and neighboring plants using a copper-based bactericide. Follow the manufacturer’s rate and timing directions found on the product label.

Solutions: The solution for a dried out plant depends on the cause, so determine the cause before selecting a treatment method. Adjust your watering: Stick your finger in the soil near the roots. If it feels bone dry or overly saturated, you need to adjust your watering frequency accordingly. Prune back dead foliage: Snip off any brown stems and leaves on the plant to make space for new growth. This encourages the roots to send up fresh stems. Move to a proper environment. This may involve decreasing or increasing sun exposure, depending on the species. Decrease fertilizer applications. If you have applied too much fertilizer, you can repot plants with fresh potting soil. Wait. If your plant has dried out as daylight is decreasing, it is entering dormancy. Decrease watering and wait until the plant resumes growth.

Solutions: If the yellowing and drying of leaves and flowers is a natural progression due to age, nothing can be done to slow or stop the process. Once hormones within the plant begin the process of senescence, it’s irreversible.