Have you heard of the 8x8 rule of water consumption? It states that you should drink eight 8-oz glasses of water per day. From my academic background, I know that water is the solvent that makes all the chemistry in our bodies happen, and it's the lubricant that makes all the parts move smoothly. Still, there is a lot of debate around the benefits of the 8x8 rule of water consumption. While the exact amount is debatable, nobody debates that healthy water consumption is essential. I know that my wife believes that when she focuses on drinking more water, she generally feel better. Similarly, water for plants is critical. I decided to explore the parallels between the benefits and risks of humans drinking 64oz of water (or much less) each day and those of over- or under-watering bonsai trees. Because in both cases, too much or too little water causes problems that may not immediately be apparent.
When humans drink too little water
Dehydration happens when we don't consume enough water or fluids to account for the water we lose over the equivalent course of time. Symptoms of dehydration include muscle fatigue, reduced cognitive processing, dizziness, confused or dazed states of awareness, infrequent urination and dark colored urine, and dry mouth. Without water, the average human can only survive for three days.
You might think you're getting enough fluids when you drink a few cups of coffee in the morning, and a lovely glass or two of wine with dinner, but coffee and alcohol have long been blamed as diuretics, causing dehydration rather than hydration. Opinions differ on whether or not this is true.
Under-watering bonsai trees
This is the leading cause of death in plants. Wilting is a reaction to inadequate water and serves to reduce water loss, making the leaf surface exposed to less sun and wind. Wilting occurs when the rate of loss of water from the plant exceeds the absorption of water in the plant. This can be the result of too little water availability, or an inability to absorb available water due to poor root health. Die-back can occur as well, a condition where the tree begins to die from the tip of its leaves or roots backward.
When humans drink too much water
So, is the 8x8 rule actually good for you? Could it cause problems that are less severe than "hyponatremia" - combination of conditions where the kidneys cannot excrete enough water to keep up with intake. Less severe problems are often not documented as people recover quickly when the situation does not prove fatal.
In 2007 a woman in Sacramento, CA died after drinking over 2 gallons of water in two hours for a radio station contest where she could win a video game console. Water toxicity is the condition where the amount of water in your body exceeds the body’s ability to process it, resulting in a change in the balance of chemicals in your blood and in your brain. Specifically, the most serious danger normally comes from dilution of sodium and potassium ions which affects the ability of cells in the body to absorb nutrients through the cell walls.
Over-watering bonsai trees
This is the second leading cause of death in plants. The confined nature of a bonsai container means that the conditions that allow success are up to the owner of the plant - too much water may cause infection by root pathogens. Take care to water when your plant needs water and to allow the soil to dry at least slightly between watering. Different species are adapted to different soil conditions. While a Juniper or Grewia may be adapted to a wide variety of soil conditions, Japanese Black Pine and other species prefer drier soil and typically suffer when exposed to prolonged wet conditions.
Even with adequate water uptake and root health, under some conditions certain plants can have water stress that results in browned needles or leaves on the plant, known as tip burn. Inability to absorb adequate water can actually be the result of fungal root infections caused by over-watering. This leads to the counter-intuitive situation where you should water your tree less to avoid wilting. However, modern science has created a remedy that will remove root-rot inducing organisms (actually oomyces, not fungus); treat your tree with a drench of root fungicide rated to control soil pathogens that cause root rot, and then follow up with beneficial bacterial strains that inhibit rot.
Water, Water, Everywhere
Water consumption is probably the single most important thing that you have to do every day to ensure that your body remains healthy, flexible, and capable. Watering your bonsai is probably the single most important thing you do on a daily, or at least semi-weekly basis to keep your plant healthy and growing. However, in both cases - people drinking water, and people adding water to plants - excess is best avoided and attention to the signs of danger either from the human body or the plant body are best carefully heeded.