If you want to know the secret to happy, healthy houseplants, look no further than your watering can. Too little hydration will stunt developing vegetation, while too much water can drown plants and promote the growth of mold and disease. Potting medium, humidity, and temperature also affect plant hydration and should be taken into account.
How Often Should You Water Your Plants?
Water your plants neither too much nor too little. Excessive care can kill plants faster than neglect. The watering needs of various houseplants under one roof can vary greatly.
This diversity is determined by many factors, so there’s no universal answer to the question, “How often should I water my plants?” Wilting leaves are a clear sign of dehydration. These and other physical changes require immediate attention. Water your plants right away, or they may suffer damage or even die.
On the other hand, black, mushy spots or mold are signs of overwatering. Plants should receive only the amount of water they can absorb in a single watering. They won’t thrive if their roots are constantly wet. Be sure to pour off any excess water and consider whether the problem lies with you or the soil.
Potting Medium Types
Plants should never dry out completely, but constant saturation is harmful to them as well. Achieving the right balance often comes down to the quality of potting medium rather than the owner’s green thumb. The choice of potting medium should depend on your plant’s type and your local climate. Ultimately, ensure the soil is suitable for the plant species.
For example, orchids require fine or coarse bark, while African violets and cacti need different types of potting mediums. Hydroponics gel, a non-soil medium, is another option. Regardless of the medium, horticulturists agree that all mature plants benefit from having only the top two inches of their potting medium dry out. In general, potting soil should act like a sponge, holding moisture without becoming waterlogged. (Although plants can be grown in sponges, I don’t recommend it.)
A good multipurpose potting mix typically contains a blend of dirt and organic matter. Some commercial soils contain no dirt at all! The mix should be dark in color, have no unpleasant odor, and pass the hand-squeeze test. Squeeze a handful of the soil; it should briefly hold its shape but crumble when poked. Too much of any one component—such as sand, clay, or peat—can deprive your plants of the proper balance of water, nutrients, and aeration.
Heat and Humidity
Humidity requirements vary by species and are directly affected by the medium in which houseplants are potted. Tropical plants, for example, thrive in high humidity. Their soil should retain more moisture and mimic the spongy rainforest floor. A spray bottle can help hydrate the foliage of your tropical plants. Alternatively, place the plant in a container with a layer of rocks and water at the bottom. While the plant won’t touch the water, it will benefit from the moisture as it evaporates.
Many common houseplants, such as those found in supermarkets, do well in low humidity. These plants generally don’t need misting or special care. You can place them in a room with a window, water them when the topsoil is dry, and forget about them. These plants typically thrive in multipurpose potting soil, which should be changed annually to maintain proper aeration and drainage.
No matter the humidity requirements, problems arise when temperatures drop below what the plants can tolerate. Keep your thermostat set no lower than 65°F (18°C) to support plant growth. However, this doesn’t mean you should maintain a constant temperature. In fact, temperature fluctuations can benefit plants by mimicking natural conditions. Many species need these variations to bloom.
Leaf Shapes and Density
Plants with larger leaf surfaces transpire moisture more quickly, while those with lower leaf density store less water. Think about dehydrating fruits and vegetables in the fall: thicker pieces take longer to dry. The same principle applies to your houseplants, so pay close attention to the watering needs of plants with thin, elongated leaves.
If you find that your plants are drying out too quickly, continue watering them as needed. A thicker potting mix might help retain moisture. Also, consider where you place your plants in the house. Thin, long leaves may dry out faster if exposed to direct sunlight or drafts, such as near a fan.
On the other hand, plants with too much water should be watered less frequently and may need to be moved to a new location. Plants with thicker, shorter leaves typically tolerate direct light better and aren’t affected by air movement as much. By finding the right spot for each plant, you’ll be closer to establishing a successful watering routine.
Vacation Watering
Various systems are available to water your houseplants while you’re away for an extended period. If you can’t rely on a trusted neighbor, a houseplant watering system might be the solution. You can create a DIY system by filling a plastic container with water, sealing it, and running wicking material from the container into the soil.
Another method involves lining cake pans or deep cookie sheets with quilter’s batting. Pour water into the pans until it pools around the batting, then place your potted plant (without its drainage plate) on top of the batting. Be sure to experiment with these methods before leaving to ensure they’re appropriate for your plants.
Hydration crystals are another option. Sprinkle them on the soil before watering your plants. These crystals absorb water and expand, releasing moisture as the plant dries. They work especially well with potting mediums that aren’t regular soil. However, be aware that these crystals can promote mold growth and prevent proper drainage, so you may need to replace the potting soil upon your return.
Always be mindful of your plants’ watering needs. Just as you wouldn’t let your car’s gas tank run dry, don’t let your plants dry out completely before watering them. On the flip side, if a plant is standing in water or if the top layer of soil is already saturated, it doesn’t need more water.
