Having indoor plants is a great way to escape the heat of summer while flexing your green thumb. However, it can be tricky growing indoors due to low light levels. While light is the most critical factor for growing healthy plants, it also tends to be the most limiting. Understanding your home’s light conditions, choosing the right plants, and adding supplemental lighting can set you up to grow healthy houseplants.
Not all light sources provide the same quality of light. Direct light is defined as the sun directly touching the plant’s leaves with only window glass between the sun and the plant. When the sun comes in the window, your plant will cast a crisp shadow. Bright indirect light is when the area is highly illuminated and the plant has a clear view of the sky, but the sun isn’t directly touching the foliage. In this lighting, your plant might cast a fuzzy, soft shadow. The area around your plant also affects light intensity. For example, light colored walls or surfaces reflect light and increase ambient light while dark walls will absorb light. In low light areas shadow will be faint.
The direction your windows are facing determines the intensity and duration of light your plant receives. South-facing windows generally provide the brightest, most intense light throughout the day. East-facing windows receive direct light in the morning and bright, indirect light throughout the day. West-facing windows receive bright light during the day and strong intense light in the afternoon and evening. Western windows also tend to be much warmer than eastern windows. Finally, north-facing windows provide the lowest light levels, receiving indirect light throughout the day.
Window direction is only part of the equation. Obstructions such as trees, deep roof eaves, and nearby buildings can block sunlight. Windows also accumulate dirt over time blocking a significant amount of incoming light. Finally, consider the distance from the window. Light intensity rapidly decreases as you move away from a window or light source. A south facing window with strong direct light can become a low light area not suitable for growing if a plant is moved just 8 feet back.
The light levels in your home determine what plants you can successfully grow. Some plants require significantly more light and others may get burned if given too intense light. Indoor plants that have the highest light requirements are cacti and succulents, citrus, and orchids. Begonias, spider plants, amaryllis, peperomia, ferns and monsteras require a medium amount of light. The house plants that require the least amount of light are zee zee plants, pothos, philodendron and peace lilies. Most house plants fall into the first two categories; fewer are suitable for low light conditions.
When not given enough light, indoor plants can become ‘leggy’. This is when they stretch for light and grow spindly. They may lean toward the light, fade in color, and have poor growth. If you don’t have enough natural light, supplemental light can be added. LED lights are the most common grow lights on the market right now. They are energy efficient, don’t produce much heat, and are available in a wide variety of styles and sizes. Fluorescent and incandescent can also be used. Fluorescent lights are moderately energy efficient and have a cheaper up-front cost than LED. Incandescent are the cheapest up-front but create a lot of heat, are energy inefficient, and contain high far red light which causes plants to stretch.
When purchasing grow lights, you will notice that there are different color options. Sunlight provides red, orange, yellow, green, blue, indigo, and violet light, also known as full spectrum. Plants primarily utilize red and blue light. Lights may be labeled blue, red, or white light (or full-spectrum). Check the packaging to see what type of light is emitted before purchasing. Blue lights are suitable for starting seeds, growing leafy greens, and non-flowering house plants. Red light is suitable for growing flowering plants and white light is good for growing most plants. Add a timer to your setup to make your life easier. In general, seedlings need 16 to 18 hours per day, foliage houseplants will need 12 to 14 hours, and your flowering houseplants need 14 to 16 hours.
By understanding the light levels in your home you will be better prepared to care for your indoor plants. For more information about growing houseplants, contact North Carolina Cooperative Extension- Richmond County Center at (910) 997-8255. To learn more about workshops and other educational opportunities, visit our Facebook and check out the Events page on our website.
