Do you have a green thumb, or aspirations to such? Do you ever get that sense that you relate better to something inanimate than to Billy Bob, your neighbour (this may depend a bit on who/what Billy Bob is, as well as the size of his truck)? Or on the flip side, do you find the mysteries of the Plant Kingdoms beyond you? Never fear. Whether the world of photosynthetically-active green “people” calls or repels you, there is hope. The two sides aren’t that different, at all.
Most of us humans have a reasonable understanding about what we need to live and thrive. Plants are very much the same. Meet the basic needs and you are good to go. As a horticulturist, I am strongly inclined to explain things in terms of what plants do and how they act and react, sliding dangerously across the line that divides plant appreciation and the feeling that plants are live and interactive.
Regardless, please allow me to outline how plants and humans aren’t all that different. For the plant-lovers, you’ll recognize the truth and maybe appreciate humans a bit more. For those that don’t “get” plants, maybe you’ll gain a better appreciation and understanding about what makes those plants tick. A few more plants will live and we’ll be the better for it.
In Mosby’s Medical Dictionary (8th Edition – 2009), it defines the basic needs of humans as “the elements required for survival and normal mental and physical health, such as food, water, shelter, protection from environmental threats, and love.” Without these things, humans can’t survive. Indeed, in times of crisis, we work hard to restore a supply of the basics, before trying to get things entirely back to normal.
True to form, plants are really no different. Plants need sunlight, air, water, nourishment, adequate temperatures and freedom from pests. Let’s delve into each, since we want to learn more about how plants and humans are similar.
The fundamental function of plants is to capture and harness the energy the sun’s rays, converting it into products such as sugars, through processes that take in carbon dioxide (CO2), water (H2O) and other elements and releasing oxygen (O2). Without light, plants can’t capture the energy they need, create the food they (and others in the food chain) need and we start running a bit low on oxygen.
In the absence of light, or when light gets low, plants tend to be light-coloured or pale, even whitish. Growth is weak, plants become stretched and spindly. Over time, they diminish and eventually fall prey to illness or just die from starvation (essentially).
Now, the non-plant people may be thinking, “We aren’t plants. We don’t need sunlight to survive. Why bother to even bring it up?” You are partly correct. However, I think that a good argument can be made that we do need sunlight to be healthy AND happy. When we don’t get enough sunlight (and we need the sun to get Vitamin D – other than through supplements), we aren’t healthy. Picture that weird cousin (you know the one) that never leaves the basement or house. We become pale and anemic, pasty and weird (debatable).
The medical community now recognizes a disorder known as Seasonal Affective Disorder (SAD), which results in lack of energy, fatigue and depression, with typically “normal” activity in summertime. SAD is also known as winter sickness, seasonal depression, winter blues, etc. The basic treatment for SAD is simple: Sunlight.
People and plants that get too much sun have a similar reaction. They experience tissue damage and don’t function properly for some time (remember how much it hurts to move with a lobster-esque sunburn).
We all need air to breathe. Specifically, humans need oxygen. Plants need air, specifically CO2. At higher levels of CO2, plants really thrive, because they become more efficient. In conditions without any oxygen (anaerobic), both humans and plants don’t thrive. They die. Similarly, both plants and humans do poorly when air becomes stale and stagnant or polluted. A bit of air movement and replacement of the air goes a long way to a healthy life for both of us.
Humans need water to stay alive. We also use it to wash (ourselves and other things in our lives) and to stay cool and refreshed. We are hydrated organisms. So are plants. Plants are comprised of up to 90+ per cent water. Plants need water to maintain their cellular structure, for their physiological processes and reactions and to move elements things around within the plant. Plants need a constant supply of water to stay hydrated and react very strongly to changes in both the soil moisture content and the relative humidity of the surrounding air. Plants don’t sweat but they do make adjustments to ensure that there is fluid moving through them at the appropriate rate. Plants can be protected from overheating and from freezing by the application of water. Water is necessary to wash off the plant or plant parts, certainly after harvest.
If humans or plants are exposed to too much or too little water, they don’t do well.
Whereas plants can produce their own “food products” from the sun, air and water and mineral elements in the soil, humans have to consume their nutrients (from plants or other animals). Regardless, the need for food or nourishment is consistent between humans and plants. When we think of food or nourishment for plants, we think more in terms of the supply of mineral elements (such as nitrogen, phosphorus, potassium). Plants that are supplied with enough nutrients are healthy and productive, grow at a good pace and are more resistant to attack from disease or pests.
Undernourished plants are weak, off-coloured and unproductive and may die. Plants that get too much nutrition become unhealthy, in that they grow rapidly and weakly, often becoming soft and lush or tender and often sicken more quickly. They can produce less fruit (and more leaves) and may “forget” to shut down for the winter. Most of those descriptions sound a lot like what happens to over or under-fed humans.
Protection from the elements:
Humans need shelter. This represents a protection from temperature extremes and other weather elements. Plants need to be protected from these same things. Plants (just like people) grow better at different temperatures, typically not the extreme ones. If it gets below freezing (or even just colder), humans put on layers of clothing or go inside their homes. Plants adjust somewhat, but then will eventually die. The use of greenhouses, cold frames, or other plant covers (essentially “plant clothing”) are all that we can do to give plants a break from the colder elements. Shading or misting is necessary to cool off plants when things heat up.
Humans need their personal space (some people forget this) and certainly do not thrive when they are packed like sardines into any particular space for an extended period of time. Plants are no different. Whereas the initial affect that many humans experience is probably more psychological than physical, plant overcrowding result in direct completion for limited resources. Plants that have (too) close neighbours will be weakened or may be literally choked out (think of weeds). The stagnant air that can develop will result in an increase in disease or other issues.
Plants that lack competition thrive to a certain extent, but also become a bit overgrown and wild. Humans that lack contact with others become a bit wild or anti-social.
Freedom from pests:
No one likes to be sick, whether you are human or green. We all suffer from various ailments and attack from different pests. Humans take medicines. We treat plants with “medicines” to try and fight off attack. Both species become a little stronger if we are attacked in limited degrees. But in general, we need to be free from pests or disease if we are going to thrive.
The original definition of basic human needs included a need for love. It is interesting, but certainly not all that surprising. We thrive on relationships, or are at least healthier contributors to society (remember your weird cousin?). Are plants that different in this need for companionship or relationship? They rely on us for a supply of nutrients, water and support (physical). We protect them from the elements, from excessive competition and provide a bit of grooming. Some might consider it a utilitarian and emotionless relationship, but anyone that has shed a tear after a frost or a big wind, knows that there is more to it.
When you lay it out, it isn’t hard to see the similarities between humans and our green friends. We both need some basic elements to survive and to really thrive. The only thing that is maybe a bit different is that plants need to grow in soil (to supply structure/support and nutrients and water). Humans don’t necessarily need dirt between our toes, do they?