Improper watering as the n°1 cause of a plant's demise

From articles to interviews, we learnt that the most recurrent reason why a plant didn’t survive is due to excess watering or dehydration. This could either be that the owner does not know how much water the plant needs and ends up overwatering the plant, or the owner has totally forgotten to water it. This is why Kanopy Technologies is focusing on the watering aspect of a plant’s well-being as a first product offering.

When we forget to water the plant, its roots dry up and after a few days, the plant start to wilt.  When we water way more than the plant can absorb in a day, the roots get suffocated and thus cannot get enough oxygen. As a result, root rot occurs and this is the most frequent cause of a plant’s sudden death.

One nurseries from Michigan, USA, listed the top 7 reasons why plants wilt and what can be done to minimize the risk. Note that the top 2 reasons are linked to water.

  1. Overwatering– this is a common mistake with growing indoor plants. We often water them as much as those growing outdoors but forget that evaporation is much lower inside. So plants end up sitting in very moist soil and their roots begin to struggle.
  2. Lack of water– the flip side of the first problem is not watering them enough. If your plants are wilting because the soil has become too dry then the obvious solution is to begin watering them and keep this constant until the plant picks up again. Container plants have a knack of drying out quicker than those growing in the ground. So, the best way to resuscitate your pot plants is to plunge them into a bucket of water and hold until all the air bubbles have subsided. Note: this is only for extreme cases.
  3. Too much sun– plant wilt often happens when you’re growing them in the wrong position or if indoors, the plant is too close to a window. Too much sun for a shade loving plant is like too much social activity for an introvert.
    If outdoors, try moving your plant to another garden bed where it is less likely to be scorched by the sun’s rays. Indoor plants may need to be moved away from the window but still where it can receive some indirect sunlight.
  4. Not enough sun– and this ties in with the overwatering idea. Plants wilt sometimes because they’re not receiving enough sunlight. Picture an extrovert confined to a cubicle office space every day and you’ll understand the problem. The answer, again, is to move them.
  5. Root-bound plants– often plants can outgrow their containers if they’re not transplanted every year or two. Once a plant gets too large for its pot, it struggles to draw nutrients and moisture from the soil – if there is any left, that is.
    The answer is to repot your plant into a larger container and use some quality potting mix as its growing medium.
  6. Too much fertiliser– overzealous gardeners can cause plant wilt just by feeding it too much. When adding fertiliser to a plant’s growing medium, whether it be soil or potting mix, take into account the size of the plant and when you last fed it. Plants don’t usually become obese, they just die. Try using slow release fertilisers where possible and usually they should only be added at the start of the growing season and again during flowering times.
  7. Disease– plants can often wilt as a result of an infection as well. There are a few main types of plant wilt related to disease, namely – Fusarium wilt which is a fungal disease common to cotton, tomatoes and palms. This type of wilt can be controlled via a fungicide which should be used as per the directions. Other forms are Bacterial wilt and Verticillium wilt.

Other causes include temperature, pest, chemical incompatibility and lack of nutrition.

The water's role to a plant

Water is the essence of life. But what does water do for a plant? A plant requires water as an essential ingredient of photolysis, the photochemical stage of photosynthesis where water is split using light energy. This is the part of the process in which a plant obtains its energy, and thus illustrates the importance of water to a plant.

Water helps a plant by transporting important nutrients drawn from the soil through the plant. Without enough water in the cells, plants droop. Therefore, water makes a plant turgid. It also carries the dissolved sugar and other nutrients through the plant. Without the proper balance of water, the plant is not only malnourished but also physically weak and cannot support its own weight.

Water travels up a plant through the root system then through the stem and into the leaves, flowers or fruit. To be precise, water molecules move up through xylem vessels, which are like capillaries, into the different parts of the plant. It also helps the plant to maintain proper temperature as water evaporates. When moisture evaporates from the surface area, it causes the plant to draw more water up through the roots to replace what was lost.

Watering indoor plants

Different types of plants require different amounts of water. As for outdoor plants, there is no way to control the amount of rain your plants get if your area is often rainy. Therefore, you need to make sure that the soil has proper drainage, because too much water will affect plant growth just as much as too little.

As for indoor plants, the amount could depend on the type of plant you have, where it is located, how old the plant is, the type and size of the pot, the room temperature and humidity. Even soil conditions come into play as some soil holds more water than others.

Respecting each plant’s watering requirements is crucial for the plant growth. Each plant is unique, and what works for one may very well kill another. Fortunately, there are only three basic categories that define watering techniques, and each plant falls into one of them.

  • Foliage plants are those appreciated for their beautiful leaves. They need to be watered thoroughly during the growing season, from spring to fall. In winter, during their resting period, allow the top level of the soil to dry out before watering again.
  • Flowering plants, or at least the vast majority of them, should be kept moist, but not wet, all the times.
  • Succulent and cacti are used to dry climates and can keep water for months in their foliage. Their soil should be kept between moist and dry from spring till fall, but in winter these plants should be barely watered at all.

Examples:

1. Poinsettia

Poinsettia is commonly known as Christmas flower or Christmas star. Very few people know that its real name is euphorbia pulcherrima, which means “the most beautiful“. This plant, used by aztecs for dying their clothes hundreds of years ago, comes from Central America and southern Mexico, where it can grow up to four meters high. And yet, when we buy it for Christmas, it starts withering almost immediately and ends up in the garbage bin, rarely lasting till March. So what is the secret?

Poinsettia fears cold temperatures (below 13° C), rapid temperature changes and overwatering. Despite all the care, its leaves start to fall in March: the plant enters its dormant state. When this happens, gradually reduce watering and keep the plant fairly dry till May. Then start watering as normal again, and when new shoots start to develop, re-pot Poinsettia. As the days shorten in October, make sure that the plant has 12 hours of sunlight and 12 hours of complete darkness per day, not more and not less. This means adding artificial lighting as needed and covering poinsettia with the box during the night.

And then, the most beautiful will brighten up with its bright colors just in time for Christmas.

On the left : Poinsettia irrigated with the help of Kanopy25. On the left : Poinsettia irrigated manually by touch and feel.

On the left : Poinsettia irrigated with the help of Kanopy25. On the right : Poinsettia irrigated manually by touch and feel after 3 months of test.

2. Citrus 

Citrus normally requires only one watering per week, and once every 15 days in winter. Beware of excess water, which could make it lose its leaves or cause the roots to rot.

3. Ficus

Ficus thrives in the moist atmosphere and loves frequent watering. Make sure to water it every three days in summertime, and once a week during the rest of the year.

4. Anthurium

Anthurium loves water like nothing else. Maintain its regular humidity by spraying water regularly on its leaves. Ideally, position a pot over a bed of pebbles, and keep them moist. During the summer, water your anthurium as soon as its soil is almost dry. From October to February, make sure to reduce watering gradually and allow the top level of soil to dry. Keep spraying water on the leaves from time to time to keep the plant from withering.

Frequency

  • Season
    The majority of the plants require more frequent watering during the blooming period, and less water during wintertime. It is crucial to adjust the watering frequency, as too much water will make the roots rot.
  • Location
    But even for the simplest plants without specific resting cycle, watering frequency depends on many other factors. Those on sunny windowsills dry out much more frequently than those in the shadowy corners.
  • Type
    Even two plant neighbors on the same terrace may require a completely different water quantity and at very different intervals – just because they are different species!

Efficient watering

As automating irrigation based on plants’ needs is something that can save water and money in the long term, it is also recommended to water efficiently and surprisingly, less is usually better. According to studies made by the University of Georgia and the University of Maine who have been making researches on the water needs of annuals and perennials, many plants actually need much less water than most people expect.

The research include steps to water the plants in the morning, followed by draining for 30 minutes. The pots are then weighed individually and the process is repeated in 24 hours. The decrease in weight is the amount of water used by the plant during the day. The weight difference will of course differ from day to day but it will give a good idea of how much the plant actually needs!

The main environmental factors that affect water use are light, temperature and relative humidity. Plant size also plays an important role with larger plants needing more water than smaller ones. Determining daily water use several times during the production cycle, both on warm, sunny and on cool, overcast days will provide you with valuable information for water management.

Knowing these elements will certainly help to determine the right amount of water your plant needs in the environment it is in.

The study mentioned that a substrate moisture content of 20% was enough to grow quality plants and there was a good correlation between plant growth and the amount of water applied. The study indicated that controlling irrigation can be an effective method of controlling growth.

Another study mentioned that watering according to the plant’s needs would save not just money, but time as well. Furthermore, it would reduce the probability of contracting diseases.

Watering according to a plant’s needs “should minimize disease pressure to a great degree and allow us to use a reduced rate of fertilizer, which saves costs to growers and prevents potential runoff issues associated with that,” said Chris McCorkle of McCorkle Nurseries. “And, ultimately, it will help us improve plant quality.”

Let the soil dry between watering

Some plants like a little dryness before the next watering cycle. Florists and experts also recommended to let the plant dry a day or two before the next watering cycle, but not wait until the soil pulls away from the side of the pot.

Signs of dehydration and overwatering

Stem and leaf wilt signal dehydration, but you should avoid waiting for this sign. In addition, the soil mixture may pull away from the side of the pot. At this stage a plant is stressed, and repeated treatment of this sort is ill advised.

Signs of dehydration:

  • Leaf growth is slow.
  • Leaves become translucent.
  • Leaves or flowers drop prematurely.
  • Leaf edges become brown and dried.
  • Lower leaves curl and yellow.

Early signs of overwatering:

  • Young and old leaves fall at the same time.
  • Root rot–mushy, brown possibly odorous roots–are seen in pot bottom.
  • Standing water noted in container underliner.
  • Flowers become moldy.
  • Leaves develop brown soft rotten patches and fail to grow.

Methods to measure soil moisture

Manual

There are a few simple things you can do to check the amount of water in the soil and ensure that there is the correct entry of water in a plant. One of the quickest ways is to just put your finger in the soil, up to your knuckle. If the soil is moist, it has enough water; if it is dry, you need to water the plant. If the soil is pulling away from the sides of the pot, it needs more water and may even be in need of rehydration.

Horticulturists and experts also suggested weighing the pot to determine if it is time to water. One way is to note down the weight before and after watering and keep track of the delta. With time, one will be familiar with the plant’s water contents just by telling from the plant’s weight.

Digital

Among the many plant care devices, there are conventional soil moisture sensors that works with 4-6″ pots and some would go beyond 6″ pots. Conventional moisture sensors depend greatly on the type of substrate and the type of plant. However for large potted plants such as palm trees and other indoor trees whose pots are often too deep to allow a comprehensive moisture measurement from conventional sensors, it will be hard to measure the overall moisture level of the soil. 

There are also connected moisture sensors that comes along with a smartphone app that gives data of moisture level. If all you need is data, then these connected sensors should be sufficient.

Advantages of using the Kanopy25

As mentioned in the previous paragraphs, weighing the plant is becoming a recommended method to assess a plant’s watering needs, in addition to other signs such as leaf colour, growth and curling, etc. The key technology in Kanopy25, and which differentiates it from other plant care devices that usually use a moisture sensor, is the use of a load cell to weigh the plant and, more specifically, to measure its gain and loss of water. Its load cell has a very high resolution in order to track changes of a few grams for plants that weigh up to 40kg (90lbs). The integration of a single beam load cell and the requirement to hold a 40kg potted plant lead to some design challenges that were later solved using a mixed assembly of high resistance plastic and high resistance steel.

In the case of Kanopy25, we do not need to know the type of substrate or the type of plant. The weight is a precise indication of the amount of water consumed by the plant. Once the target weights are set, the Kanopy25 enables a precise and repeatable watering cycle. Either one chooses to water the plant oneself, through a third party or by an automatic Kanopy25 pump, the watering cycle can now be fully controlled and measured. Having the data of the water volume poured and consumed, we will be able to learn more about our plants’ actual water consumption and therefore provide an optimized care for a healthier plant by watering efficiently.

With the utilization of SigFox network, a dedicated IoT wireless network, users will no longer need to use their WiFi and cut off the hassle of configuring WiFi connection. SigFox connects the device automatically and is secure. It also allows very low energy consumption and therefore has an autonomy of 6 months. 

As for a short range connectivity (and to allow over-the-air upgrades of the firmware), Bluetooth Low Energy will be used. After surveying the testers of our first prototypes, integration of an automatic pump in the Kanopy25 is enabled so that the irrigation is kept in check when the user is absent or very busy.

In the end, by watering based on the substrate’s water content, the plants are eventually in control of their own watering needs. For instance, in summer when the weather is warm and sunny, the plants use water quickly which will result in a rapid drop of water content and therefore more frequent watering and vice versa for winter.

As a solution, Kanopy25 helps plant owners to measure water content effectively, control watering amount and cycle, provide time charts for learning purposes, which are the elements to grow quality plants. Best of all, it can operate automatically and be used anywhere without WiFi. Plant care has truly been simplified!

References

More reads

  • Rodale’s Encyclopedia of Indoor Gardening, Rodale Press, 1980. Anne Halpin, editor.
  • Indoor Plants, Comprehensive Care and Culture, Chilton Book Co., 1977. Dorie Hirch, editor.
  • The A to Z of Houseplants; The A to Z of Cactus and Succulents; The A to Z of Bulbs. House Plants, Readers Digest Association Inc., 1990. John Brooks, contributing editor.
  • Success with House Plants, Readers Digest Association manual, 1985.
  • New Houseplants Book, Better Homes and Gardens, Books , 1985.