Indoor Plant Care 101
House plants. Photo by Dr. Leynar Leyton, UF/IFAS Ornamental Plant Breeder and Assistant Professor in Environmental Horticulture.
As we approach winter, and temperatures start to drop, you might have brought some plants inside your home. Or maybe you were at the garden center and fell in love with a unique lush plant, but as you get home, you are now wondering how you take care of your newest indoor plant… I believe I might can help! I will try to cover the basics of indoor plant care in this short article, so your plants thrive inside your home. These recommendations work not only for new plants that you bring home, but also, for your current house plants.
–Let’s start with light
One of the most important factors that affect house plants is light. Plants make food out of light through photosynthesis. Without enough light, they cannot produce enough food to survive. Plants can be divided into low, medium, high, and very high light requirements. These four categories are very helpful when you try to decide where to place your plant at home. Now the question is: How do you know the light requirements of your plant? Your first bet will be the plant tag or label. Plant labels usually contain the name of the plant and its light and water requirements (we’ll talk about water requirements in a bit). If they only have a name, a quick google search will help you with the light requirements of your plant.
Generally speaking, and without taking into consideration the layout of your home – think trees, windows treatments, size of your windows, other structures
House Plants under artificial / grow lights. Photo by Dr. Leynar Leyton, UF/IFAS Ornamental Plant Breeder and Assistant Professor in Environmental Horticulture.
nearby, and time of the year – eastern exposed windows will provide the best light conditions for most indoor plants, with direct sunlight from sunrise until approximately midday. Windows with a southern exposure provide a long range of light intensities during the year. For example, during this time of the year (as we approach winter) and during most of the daylight hours in winter, the sun will shine throughout the room. In summer, the sun would be farther north, making the sunlight enter the room only after midday. Western exposed windows have very similar light conditions to southern exposed windows. The windows with the least amount of light year-round would be a northern exposed window, as the United States is in the northern hemisphere and most of the sunlight comes from the south.
Plants will tell you if they don’t have enough light. One of the most noticeable signs is that your plant will not grow, and the internodes (the distance on the stem between leaves) on new growth would be much longer than the internodes on older parts of the plant. Other signs could be that the new fully expanded leaves are smaller – and with a much lighter green color – than the older leaves, as well as dead old leaves. If your plant is not receiving enough light, there is still some things you can do to help. You can move the plant closer to the window or move the plant to a brighter room, either with a better exposure or a room that has artificial lights turned on during the day. Light intensity is important but also the number of hours your plant is exposed to light. This is very important if you decided to invest in artificial lights for your plants. You do not need a very intense light, if you keep it on for a longer period of time – say 16 hours. Whatever you do, keep in mind that too much light can be damaging to plants. You need an adequate amount of light for your plants, not an excessive amount of light. Also, be mindful when moving a plant from low light conditions into high light conditions, for example direct sunlight, as leaves can be burned or look bleached.
Thaumatophyllum bipinnatifidum showing sign of low light exposure. Photo by Dr. Leynar Leyton, UF/IFAS Ornamental Plant Breeder and Assistant Professor in Environmental Horticulture.
-What about temperature?
The second major factor that affect your house plants is temperature. We feel comfortable in temperatures ranging from 72 to 82 °F. Indoor plants are originally from tropical and sub-tropical parts of the world and can grow well in temperatures ranging from 58 to 86 °F. Based on those temperature ranges, house plants should do pretty good in your home. However, we need to understand the relationship between temperature and light, and how plants produce and use their “food”. When we talked about light, we mentioned that plants made food out of light through photosynthesis. Well, that is only half of the story. Plants use that food in a process called respiration, which produces energy that is used in developing new leaves, growth, and for maintenance of leaves and roots. High temperatures increase respiration, forcing plants to use more food to produce energy, reducing their efficiency. Imagine a plant under not optimal light conditions, struggling to produce some food (mainly carbohydrates, sugars, and starch) during the day. If the plant is in a warmer room of your house, all those few carbohydrates produced will be used quickly. As a result, your plant will not grow, because plants will use those sugars to maintain the current leaves, rather than use that energy in producing new leaves or roots. Another aspect to consider is that plants – like people- might like a specific temperature in the 58 – 86 °F range. Some plants like a warmer environment, and others can withstand “colder” environments. A good rule of thumb is to never allow temperatures drop below 50 °F and keep your thermostat in the 70 – 80 °F during the day, and 65 – 70 °F at night. Be mindful of “away” schedules on your thermostat or plants that are too close to a vent or heater.
-Water
The last factor I want to talk about is water. This is probably the most common and controversial topic in plant care. How often should we water our plants?
Should we bottom water or top water? Is tap water, ok? All these questions might be overwhelming, but I’ll try to go through the basic principles behind those questions so you can make your own watering decisions. Firsts of all, it is important to recognize that each plant will have a specific water requirement. Some plants require more water than others; this information should be in the plant tag when you bought it. Other factors that will affect the amount of water a plant needs are:
-Size of the plant. Bigger plants will require more water because they are bigger.
– Pot or container. Smaller pots will hold less water (they dry out faster), meaning you’ll have to water them more often.
– Soil texture or type. Some types of soils will retain more water than others.
-Light intensity. Plants under high light intensity will require more water, as water is need it for photosynthesis.
Dracena dying due to root rot. Photo by Dr. Leynar Leyton, UF/IFAS Ornamental Plant Breeder and Assistant Professor in Environmental Horticulture.
Be mindful and do not over water, or let water stand in saucers for days. Too much water, or plants in standing water for long periods of time can produce root rot, a fungal infection in the roots that plants usually cannot recover from. Another problem caused by standing water from irrigation is the accumulation of salts washed off from the soil. Make sure you discard any water that had drained into the saucer and has been in the saucer for more than a day after watering your plants. A good way to learn when to water your plants is to know and understand them: If you check your plants constantly, you’ll learn how long it takes them to use the water in the soil. You can check that by checking the “weight” of your plants. Grab the pot right after you water it and feel how heavy it is. As the days pass, when you grab the pot, you’ll notice that it is lighter. If it is considerable lighter, it’s time to water. With that information, you can make your own watering schedule, or simply check your plants every other day and water when need it. Water quality is also important, especially for green leafy plants. Now, what about tap water? The reason some people don’t recommend using tap water to water your plants is because it contains fluoride and chlorine, and leafy green plants are sensitive to these chemicals. A typical sign of water quality problems is burned tips or edges of leaves. An easy way to deal with this problem is to let your watering water sit for a few days before use it, as fluorine and chlorine will be released from the water to the air. You could also just use filtered or distilled water.
I hope this article helps you a little in the care of your indoor plants. Plants are resilient organisms and if you do make a small mistake, they will probably be ok. Remember that gardening is an art and a science!