Overwatering a houseplant prevents proper drainage, which can in time lead to root rot, a malady that causes the roots to turn mushy and brownish black from a lack of oxygen. Signs of root rot include a plant that is slowly wilting and leaves that are turning yellow and falling off. To save a plant from root rot, try removing it from the soil and washing the roots clean. Then, cut the roots back to remove the diseased tissue, and repot the plant in fresh soil after cleaning and disinfecting the container.
flickr.com via David B. Gleason
If the leaves are yellowing but not falling off, your houseplant could simply be hungry. Because the nutrients in soil become depleted over time, potted plants need to be regularly fed with fertilizer. Plants also benefit from the occasional clean slate, so homeowners should repot them with fresh soil at least once a year.
Take care when moving plants around the house. They could experience shock from rapid changes of temperature or light, which can lead to a sudden loss of leaves. If you plan to move houseplants indoors for winter, start by placing them in the new location for a few hours and then returning them to their previous spot. Gradually increase the time in the new location until the plant is ready for its complete transition.
Brown patches on the stems and leaves of a plant indicate dieback, also known as fungal disease. Isolate affected plants so they don't infect others nearby, and then remove all fungus-ridden leaves and stems. You may also need to treat the plant with an antifungal solution.
If your plant is struggling despite regular watering and feeding, it may be time to transplant it. Plants that have outgrown their pots will have uninspired growth, and you may notice water seeping out of the drainage holes immediately after watering. Purchase a bigger pot, add some fresh soil, and give that plant some room to breathe!
Related: The 10 Best Plants for Your Bathroom
Small webs around the leaves of your houseplant indicate the presence of spider mites—small arachnids that cause damage by feeding on leaves. If you spot spider mites, isolate the plant to prevent others from being affected. Then, put the plant in the sink and hose it down to remove the mites. Use an insecticidal soap to combat any lingering mites, and spritz the plant daily with water, because the pests thrive only in dry conditions.
Yellowing or wilting leaves signal many different plant problems. But if the degradation is accompanied by small, dome-shaped shells on the leaves, the plant is most likely suffering from a scale infestation. These insects suck the sap and moisture out of plants, killing them in the process. Homeowners can scrape scale off leaves with a table knife or similar object, but if you're dealing with an especially bad case, you’ll need to remove the infected parts of the plant and apply an insecticide.
Not Enough Light
Are the leaves of your houseplant getting smaller, sparser, or lighter in color? It may be suffering from insufficient light. All plants need photosynthesis to provide energy for growth; if the plant isn’t getting enough light to fuel the process, it will experience lackluster growth. To get your plant back on track, put it in a sunnier spot for a few weeks, and monitor its condition for signs of improvement.
If you’ve noticed a powdery-looking substance on the leaves of your plants, it’s likely that they have powdery mildew, a fungal disease that will eventually kill them. You should remove all the affected parts of the plant and relocate it to a place with better air circulation.
Related: 8 Plants Never to Grow Indoors
Another common pest, whiteflies suck a houseplant’s sap and cause the leaves to yellow and die. Because a large whitefly infestation will surely kill a plant and can infect others around it, you'll need to manually remove the insects by pulling, vacuuming, or hosing them off. Don't neglect the underside of each leaf, where the small winged insects lay their eggs. Finish up by applying a strong insecticidal soap to keep the pests from returning.
You Picked the Wrong Plant
If you can’t determine a cause for your houseplant woes, maybe the problem is that you've chosen the wrong variety for your space. For example, a plant that requires abundant sunlight will always struggle in an apartment with few windows and low light exposure. Do your research before buying any houseplant to ensure that you can provide the conditions it needs to thrive.
The first step to good plant care is education. Now that you have the facts about proper watering protocol, pest management, and more, you can keep those houseplants alive.
Give the special gardener in your life a little love this holiday season! Go now to see Bob Vila's best gifts for green thumbs.