Understanding light for house plants

Understanding light for house plants: Types of light and how to measure it

Houseplants and light

Misunderstanding the intensity of light is one of the most frustrating experiences when it comes to houseplants. We have vague expressions that describe the amount of light a plant needs to thrive: sun, partial sun, shade, bright indirect light, and low light. As for houseplants, with the exception of cactus and succulents and some flowering plants, most people enjoy what horticulturists call “bright indirect light”. Plant care tips leave it as it is, moving quickly to watering and fertilizing, which we as caretakers need to do for our plants. But what about the work that plants need to do? Growing and living are driven by the light of their work! If they do not get the right amount of light, all the water and manure in the world will do them no good.

“My room has no sunlight,” I often ask. But there may be a window in that room that “doesn’t get sunlight”, right? How can you tell if your plants are getting the light they need from that window? I thought about this a lot, and here is my answer: Some plants only need to see the sun as much as possible, but all plants benefit from looking at the daytime sky as much as possible.

Understanding light

Why is light not properly understood? Think about the environmental conditions we share with our indoor plants. They generally enjoy the same temperature range as we do, and we are not bad at determining whether their soil is moist rather than dry, because we can better distinguish degrees of drought by touch. Light, on the other hand, is something that animals experience very differently from plants. As humans, we use light to recognize the details around us, while plants use it to prepare their food. So, in the far corner of a room, away from any windows, a plant living in that corner will starve - we will never hear the cry of its hunger!

In fact, evolution has confirmed that we have a visual system that does not have the best measure of light intensity because we need to see what's happening in that corner of life — it's optimal for any scene to be as bright as possible. , No matter how light. Our eyes cannot tell how much light the plant in the corner actually receives. Therefore, if the light is a prerequisite for proper plant care, we need to be better at evaluating it. It is time to measure the light.

#WhatMyPlantSees Way of Assessing Light

"How bright is this place?" Instead of asking, ask yourself, "What kind of light can my plant see from this place?" Think about how this changes throughout the day and throughout the seasons. Bring your eyes to the level of the leaves below (or above) and stay planted! Follow a direct glance at the nearest window (s) and try to identify the following types of light in the range of brightness. Using this #WhatMyPlantSees checklist, you can create awareness about how much light a plant gets in a particular area of ​​your home.

Type 1, direct sun:

 This plant looks directly at the sun. This is the most intense light a plant can receive, and most tropical evergreen plants will not tolerate it for more than three to four hours. Cactus and succulent plants, on the other hand, prefer it.

Type 2a, filtered/diffused sun: The plant has a partially blocked view of the sun. For example, the sun may shine through trees or through a translucent screen.

Type 2b, Reflected Sun: Sees shiny objects or surfaces that receive direct sunlight, even if the plant cannot see the sun.

type 3, Skylight: The plant sees the blue sky on a clear day. This is an easy measurement because the intensity of the light changes throughout the day, but the amount of sky the plant sees from one position does not change.

You will find that most houseplants grow well in bright indirect light. The plant in bright indirect light should see any or all of the above types 2a, 2b, and 3 above. If the plant has long periods of exposure to the sun (by getting type 1 light), make sure the plant tolerates direct sunlight. When calculating the amount of light using this checklist, the size of your windows and the distance from the plant to the window are important. You can not zoom in on your windows, but you can move your plants. Best place for tropical evergreen plants,

Measuring light with a light meter

Using the #WhatMyPlantSees checklist in The New Plant Parent, you can learn a lot about the amount of light your different plants receive. Over time, you will develop a period of light and sensitivity to distance from windows. However, in some cases, you may want to measure the intensity of the light to test your intuition, which requires a light meter that measures a quarter of a candle (defined as the brightness of a candle per square foot. Distance). A light meter can demonstrate how quickly the amount of brightness decreases when a plant is moved a short distance from the window.

In the past, only serious farmers would invest in a light meter (you can buy a good one for less than $ 50). Now there is a corresponding application. Smartphone light meter applications — which range from free to a few dollars — are not as accurate as dedicated light meters, but they are enough to show how light intensity varies from place to place. No one will tell you, "This plant needs exactly 375 feet of candles to grow well," but you can learn a lot when you see the intensity of light decrease tenfold as you move from one side of your living room to the other. Others. In the photos for this episode, I replaced the dedicated light meter with the smartphone using the app, so you can see both in action.

As you begin to measure the light, as you gain a sense of the basic preference of your plants, you will begin to feel more attached to your plants. You know that when you measure only 30 feet of candles on a dark wall they will starve. You will smile knowing that your plant is growing happily with 350 feet of candles near the window.