Question for Pat from Stephanie: I'm setting up a new office and want to create a bit of an indoor ecosystem with a collection of potted plants. Any recommendations on the best plants what will be happy indoors (in Johannesburg) and give off the best oxygen ratio? I guess the larger question is what is the difference in types of plants and carbon dioxide to oxygen exchange. Is an aloe equivalent to a ficus, for example?
Pat’s Answer: Plants performing photosynthesis absorb carbon dioxide and release oxygen, so indoor plants can increase the amount of oxygen and reduce the amount of carbon dioxide inside a building. The resulting impact on indoor air quality depends on the level of air exchange with the outside - a tightly sealed building would benefit more from the plants than a drafty building.
The rate of plant growth is the main factor determining which plants are better at increasing oxygen levels. Fast-growing plants absorb the most carbon dioxide and release the most oxygen. Also, some plants, including orchids and succulents, continue to release oxygen at night, not just during daylight.
The U.S. Lung Institute lists the following as the Top 5 houseplants for increasing oxygen indoors:
Indoor plants also raise humidity levels inside buildings, which helps reduce respiratory and skin problems caused by dry air often found in offices. People with plants in their offices are more energized and able to focus and feel less stressed.
Indoor plants, when in a well-sealed building, also help clean the air by soaking up volatile organic compounds (VOCs). Based primarily on NASA research, the following table lists the top 10 house plants for air purifying.
For more information, see:
Claudio L. Planting Healthier Indoor Air. Environ Health Perspect. 2011 Oct; 119(10): a426–a427. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3230460/
Conklin LM. The 18 best air-cleaning plants, according to NASA. https://www.msn.com/en-sg/lifestyle/smart-living/the-18-best-air-cleaning-plants-according-to-nasa/ar-BBVyqYM
Li Q. Forest Bathing: How Trees Can Help You Find Health and Happiness. New York, NY: Viking (2018).
US Lung Institute. Top 5 Plants for Increasing Oxygen. https://lunginstitute.com/blog/top-5-plants-for-increasing-oxygen/
Wolverton BC. How to Grow Fresh Air: 50 House Plants that Purify Your Home or Office. New York, NY:Penguin Books (1997).
On Instagram, Michele asks how to transplant Bamboo that has outgrown it's containter.
This is Pat's answer:
Assuming you have the houseplant known as lucky bamboo, re-potting it is straightforward. You can either keep it in the same jar or move it to a bigger one.
If it’s growing in water, all you have to do is dump out any rocks and place the plant in a bigger vase, or to keep it in the same jar, trim back the roots by as much as a third. Then add back the rocks and water. Remember to use room temperature rainwater or distilled water, not tap water.
If it’s growing in soil, first water the plant. Then remove the plant and place it in the new, larger pot at the same soil level, firm the soil around the plant and water the new pot.
If you have a question for Pat to research, email him at email@example.com
Anne S. Writes: We are up in Alaska looking at the majestic mountains. Question is... why do trees grow only to a given elevation? Is it lack of oxygen, temp, or what???? Always wanted to know.
The short answer is temperature.
Trees will not grow beyond a certain elevation at a specific location if the climate is too harsh for survival. There are several factors that contribute to trees’ ability to grow and survive. As these factors vary in different locations, the elevation of the tree line also varies across the globe. For example, the tree line in the Teton Mountains is at 10,000 feet, while the tree line at Mt. Washington in New Hampshire is at 4,500 feet.
The primary factor that determines the tree line is temperature. According to plant scientists, plants cannot effectively build cells when the average growing-season temperature is lower than 44° F. Trees can withstand quite cold winters but need a long enough and warm enough growing season in order to build up sufficient energy reserves to grow, reproduce, and survive. The Teton Mountains have warmer and longer growing seasons than Mt. Washington has, accounting for the difference in tree line elevation between the two sites. Similarly, mountains near the equator have a much higher tree line elevation than mountains at higher latitudes due to higher temperatures in the tropics.
Other factors also influence the location of the tree line, including moisture, sunlight, wind, and soil. The tree line in the desert or on the slopes of Hawaiian volcanoes is often at relatively low elevations because the soil is too dry for tree growth. Trees often become smaller and smaller as you approach the tree line because smaller trees need less moisture and oxygen to survive than tall trees. The larger canopy of taller trees also shades the ground and makes it colder. Taller trees are also more exposed to chilling winds that damage tender growing buds.
As the planet warms, the tree line in the Canadian Arctic is much higher than it used to be due to warmer temperatures and greater precipitation. But the tree line may not move higher in other areas due to the presence of other factors such as fire or increased insect pest pressures.
National Geographic - Timberline
Northern Woodlands Magazine - Autumn 2008 issue
If you have a question for Pat email firstname.lastname@example.org! He looks forward to answering your questions!
Anna Lentz, artist, writer, and creativity coach who blogs about making a creative life connected with nature at Spring Bird.