Too much of a good thing can be bad and this applies to many things, including watering your lawn. Excess water affects healthy grass growth. A waterlogged lawn could pave the way to the spread of pests and diseases. In addition, overwatering could drown the grass plants, causing unsightly, patchy areas or yellowed vegetation.
Sadly, many gardeners have no idea that they are overwatering their lawns! The fact is, an overwatered lawn is not just the result of an unattended sprinkler. It is also caused by rains, wet summers, even humidity.
Different grasses have different hydration needs. For example, warm season grasses like Bermuda and Zoysia need about ½ to ¾ inch of water every 1 to 3 weeks. On the other hand, cool season grasses like perennial ryegrass and Kentucky bluegrass need regular watering every four to five days.
Signs of an Overwatered Lawn
These are the tell-tale signs that you’ve been overwatering your lawn:
Thatch refers to the partially broken down plant materials and roots that form a dense mat or layer on the soil surface. Usually, beneficial organisms break down thatch but overwatering could drown these critters.
When thatch is left to build up, plants and grass develop shallow root systems. This is due to the limited levels of oxygen that reach the roots. Thatch literally chokes plant life. It also inhibits the evaporation of excess moisture, which increases the risk of fungal disease and insect pests. Apart from keeping tabs on the amount of water you use to hydrate your yard, you could remove thatch with a power rake or a rotary mower.
Fungi thrive in warm, moist environments. This is the reason why fungal growth is a common problem in an overwatered yard, the excess moisture creates the perfect growing environment for destructive fungi. Red-orange colored grass is a sign that the lawn is stressed and overwatered. This discoloration is caused by the rust fungus.
Anthracnose and brown spots are also common in wet grasses. While a fungal disease could be contained with chemical fungicides, it’s much better to prevent the problem from happening in the first place to preserve the health of your lawn as well as the microorganisms that live in it.
Some weeds thrive in over-watered lawns such as smooth crabgrass and yellow nutsedge. The problem with weeds is that they steal nutrients from other plants and grasses. And if the weeds grow tall and thick enough, they end up creating shaded areas, inhibiting grass from harnessing sunlight for food. In addition, some weeds develop shallow rooted clumps that spread on the soil’s surface. Apart from preventing overwatering, pull up weeds as soon as you see them to keep your yard tidy and weed-free. Be sure to moisten the soil 6 to 8 inches deep; don’t go beyond that to inhibit weed growth.
A waterlogged yard makes the ideal habitat for most insects and not the beneficial kind. The problem worsens once the yard becomes heavily thatched; it turns into a breeding ground for pests like imidacloprid and Bacillus thuringiensis. These pests could attack weakened or stressed vegetation. Armyworms and cutworms, in particular, love nibbling at the base of grass blades. Grubs, on the other hand, would feed on the grass roots, causing grass to dry out, wilt, and die.
Does the ground squish under your feet when you walk on it? If the ground feels spongy or if you are seeing puddles or standing water collecting in low-lying areas of the lawn, you went overboard with the watering. The problem with excess water pooling in the yard is that the nutrients from the soil are washed away. When the nutrients in the soil have been depleted, the grass will turn light green to yellow. If this happens, you have to enrich the soil with a pound of nitrogen per 1,000 square feet each year.
If this is a common occurrence in your yard, you need to build an irrigation system to eliminate standing water. If it’s rainy, hold off on the regular watering and do it only when needed. Aerating the soil is also a great way to eliminate excess water and encourage healthy grass growth. You can do this by simply pulling up plugs of dirt all over the lawn. As you work the soil, the water seeps deep into the ground, banishing persistent puddles and standing water.
What Overwatering Does to the Yard?
When the ground is overwatered, the open spaces within the soil are filled with water. This forces air out of the ground, which eventually depletes the oxygen in the soil. If your grass has shallow root systems then they are more vulnerable to the repercussions of an overwatered yard. With weakened roots, the plants and grass become susceptible to diseases and insect damage.
Worse, weeds would start sprouting because they thrive even in wet soils. Eventually, weeds would take over the yard, stealing nutrients from the grass and plants. Unfortunately, the weeds that thrive in wet soils are often the ones that are aggressive to spread and difficult to control due to their deep root systems. And since these types of weeds have deep root systems, pulling them by hand takes a lot of work.
If that's not enough, overwatering could also render some lawn treatments ineffective. For instance, amending the soil with fertilizer becomes useless if the yard is overwatered. The excess water will literally wash all your hard work away! This will make lawn maintenance very expensive for you.
How to Prevent Overwatering
Develop Proper Watering Habits
Developing and sticking to proper watering habits is paramount to keeping the yard healthy. Develop a watering schedule and always look for signs of over-watering prior to watering the yard.
Irrigation systems have yet to take certain factors - such as wind speed, soil moisture, humidity, and the type of lawn you have – into consideration so there is no guarantee that overwatering will be prevented even if an irrigation system is in place. Be proactive in terms of your watering habits and do not depend on your irrigation system completely.
If you have an irrigation system, set the watering early in the morning just before the sun comes up. Lawns need at least an inch of water a week. During the summer season, the lawn will need 1 to 1½ inches of water a week.
Do not leave the sprinklers on for long stretches of time. Modern sprinkler systems could detect soil dryness and will only release water when the lawn needs it.
We recommend watering your lawn early in the morning so the sun could absorb the excess water as the day progresses. Do not water your lawn when the sun is high because capillary pressure may inhibit absorption. Avoid watering the lawn at night unless it’s dry and/or windy because the excess moisture could promote the spread of fungal diseases.
Water your lawn deeply but infrequently. Infrequent watering is better for the lawn than over-watering. As long as the lawn is well established, the yard won’t suffer much if left under-watered. Established lawns tend to go dormant at certain seasons and they start thriving again once the rains come. When you do water the lawn, be sure that the water is reaching the sub-layers of the ground. This will encourage deep root growth.
Do not water the lawn unless you are seeing subtle signs that the grass needs more water. But don’t wait until the grass has wilted before doing something about it. Depending on the weather, water every three to ten days.
Being proactive in your lawn watering tasks is not only good for your lawn, it’s also good for the environment. To get the latest gardening tips and helpful resources, subscribe to our weekly newsletter right now!