In our Houseplant Care 101 series, we're providing the resources you need to keep your plant babies happy.
Most issues with houseplants are due to needing to adjust the watering method or the available light. And for most situations, that means too much water and not enough light. I'll cover light in a future post on plant care. As for watering, most people are more likely to overwater their plants than to underwater them.
Ideally, your plants are in a pot that allows for water drainage, either because 1) they are planted in a pot with a hole in the bottom of it, allowing the water to drain out into a saucer or 2) they are in their plastic nursery pot, which has many holes, sitting in a decorative pot (sometimes referred to as a cache pot or a cover pot), which can easily be emptied of excess water.
First, we'll talk about how to water plants. Water the plant slowly, moving the watering can around so that the water slowly permeates all of the soil, rather than pouring the water in right on the edge if the pot. This will avoid the water going straight through the pot, which can happen easily if the plant gets very dry and the soil pulls away from the edges of the pot. Watering this way also helps to avoid any dry spots. A watering can with a long, narrow spout will help to get the water to all parts of the soil and slowly. Think of the soil like a sponge that you want to thoroughly moisten.
Continue to slowly water the plant, moving your watering can around, until you first see water come out of the bottom of the pot into the saucer. After 15 minutes or so, if the water in the saucer hasn't been drawn back up into the soil, either dump it out or soak it up with a towel (or turkey baster!).
Next, let's talk about when to water the plants. If you don't know the specific watering needs of your plant, start with watering once a week. But it's far better to judge the needs of the plant by feeling the soil than sticking to a rote schedule. Most plants like to dry out a bit between watering. (Ferns and alocasias are exceptions that comes to mind.) To find out whether your plant has dried out a bit, stick your finger in the top inch or two of soil. If the soil is dry, then it's ready for water! If the top of the soil is still moist, then hold off on watering until it's dry. For plants in smaller pots (like a 4" pot), you often can just feel the surface of the soil. I like to keep my plants in their nursery pots and place them in a cache (or cover) pot, because if I'm in a hurry, I can quickly lift them up to feel if they are light, which means the soil is dry and it is ready for water.
HOT TIP: Our city's tap water contains salts, minerals, fluoride, and chlorine, which some plants do not like. After I water my plants, I fill up my watering can to be ready for the next time I water so that 1) the chlorine has a chance to dissipate and 2) the water is at room temp, which plants prefer. If you really want to pamper your plants, use distilled water or rain water.
Keep in mind that these are just general guidelines. It's best to do some research on the specific watering needs of each type of plant you have. But these guidelines can be a great starting point to making your plants happy!