The number 1 reason for plant decline and loss is… not understanding how to water plants properly. It’s not a one size fits all situation. Every plant, every type of soil or soilless mix, and every gardening method has it’s own unique requirements. However, the biggest hurdle to getting it right, is understanding what happens when you water.
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Stated as frankly as possible, water is the giver of life. It was the key component in creating life on earth, and its importance in sustaining all life is insurmountable. This rings as true for the world’s smallest organisms as it does for its largest creatures. Without water this all ends, and the plants we grow are no exception.
As plants living on Earth evolved, with a little help from the sun, they adopted the ability to receive mineral sustenance from the water. Elemental minerals in their ionic form become dissolved in soil water This article is republished here from Issue 6 of Garden Culture Magazine. It originally appeared under the title, Proper Watering Techniques. solution, and can travel along with it into a plants roots and vascular system. A remarkable task in and of itself: the water acts as courier to the minerals delivering them to the plant to use in its developmental processes.
In today’s world, plants are grown using several different methods, which have a common thread – they all require water. However, with each unique method of growing comes a different way to provide water in the most effective way. The key to success is having an adequate understanding of which watering technique is the most efficient, and productive for the style of cultivation being practiced.
Seedlings
After seeds have sprouted, and the true leaves begin to form, it is imperative that watering be done in a fashion that promotes strong initial root growth. For seedlings growing in soil-less potting mixes, the key is to provide enough water to allow for constant vegetative growth, but not so much that the medium stays to moist for too long. You can achieve this by watering thoroughly each time, and then letting the medium dry out just enough that it is not constantly wet throughout. Keeping the medium perpetually moist will lower oxygen levels around the roots resulting in poor root development.
By allowing the soil-less mix to dry out between feedings it will cause the roots to create more lateral development as it searches for remaining moisture. It’s recommended to not let the seedlings sit in standing water after the medium is adequately saturated. Also, try to not let the medium dry out so much that the plants are falling over from lack of water because this can have negative effects on the plants’ early stages of development.
Container Gardening
The proper watering technique for container growing is directly correlated to the type of medium being used. You can use soil-less growing mixes as they come, but they can also be amended in several ways to reach a certain consistency that a grower may desire. Mixes that contain higher levels of organic material, like peat moss or coco-coir, will undoubtedly hold or retain water to a higher capacity when compared to mixes fortified with different sized aggregates like pea gravel or expanded clay pebbles (LICA). The more different sized aggregates a mix has the faster it will drain, and lose moisture. This means the grower will likely have to water and fertilize more often.
Despite the obvious difference in water retention, the technique used to provide water and fertilizer is generally the same for any container plant. The important part is to water thoroughly, saturating the growing medium in its entirety. Allow any excess water to run-off, or drain, from the bottom of the container, making sure the container does not sit in the excess water for too long.
Between watering allow the growing medium to dry out, but not to the point where the plant wilts. A wilted plant has gone into water conservation mode, and the stomata has closed. With closed stomata the plant will not perform transpiration, and the flow of water and nutrients will be cut off. This can have a negative effect on the nutritional status of the plant, especially in regards to calcium intake. A plant requires a constant unhindered supply of calcium to adequately form all the various plant structures, such as leaves, flowers, and fruits. When the plant stomata remain closed, and the flow of calcium becomes hindered, it can result in disorders like “blossom end rot” in tomatoes and peppers.
Keeping the growing medium constantly damp, but not waterlogged will allow for proper nutrient uptake. It also provides a rooting environment that can support healthy growth of both roots and beneficial microorganisms. Never grow in a container that has no drainage holes.
Outdoor Soil Gardens
The composition and consistency of outdoor soils can range drastically, depending on one’s region, and the history of the soil profile. They range from loamy, sandy soils to dense, hard soils like heavy clay. Though the construction of the soil naturally varies from place to place, the central idea involved when watering is the same. Water slow and deep with as much consistency as possible.
Applying water too quickly to outdoor soil causes it to puddle up, albeit less so with sandy soils, and it runs off to collect in the lower parts of the garden. As the soil takes in the water it ends up accumulating more in the low spots, causing uneven distribution among the plants. Much like a light steady rain, when you distribute water slowly, and spread it consistently over the garden, it is better absorbed throughout.
You can accomplish this, with some finesse, using the average garden hose sprayer attachment, but the most efficient way is with some type of irrigation equipment, such as drip line or sprinkler systems.
So that is the slow and consistent part. The other part of the equation is to water deeply. This means providing enough water, delivered slowly, to ensure that moisture is reaching 1 to 2 feet into the soil profile. Strong, healthy plants outdoors have nice deep and expansive root systems. Providing moisture at deeper levels will encourage the roots to grow as far as they possibly can. You should water an outdoor soil garden this way about every 1 to 2 weeks, depending on the soil type, and environmental conditions.
Waterlogged
Regardless which of these growing techniques one prescribes to, there is always this common thread: Do Not Over Water. A simple way to state it is to not allow the soil or growing medium to become waterlogged. Something that’s waterlogged is highly saturated, or full of water.
Soils and soil-less mixes have small pores throughout that act like tiny pockets of air. The small amounts of oxygen residing in these pockets are arguably the most important thing roots come into contact with. When too much water stays within the growing medium it will fill these holes, and the oxygen will become depleted.
A lack of oxygen in the root zone will certainly lead to root death by suffocation, or devastating attack from diseases that thrive in low oxygen environments, such as pythium.
Roots aren’t the only thing that dies in such an anaerobic environment. It will also take the lives of any beneficial microorganisms that have colonized, as they too thrive in an oxygen rich atmosphere. Plants grown in mediums that remain waterlogged for prolonged periods of time are almost certainly destined for loss of yields, if not total failure.
Water is often taken for granted in our world. Yet, in its absence, life itself would not be possible. When a grower is supplying plants with this precious resource it is important to do so in a cautious, and efficient way.
By paying close attention to a plant’s overall water requirements a grower can adequately provide enough water at the right times to ensure a healthy productive plant.
Top image courtesy of Hydroponic Economics.