How to Tell if Your Onion Plant is Overwatered and What to Do

Onions need the proper amount of water to flourish. How can you tell if your onion is overwatered?

Onion plants need moist soil to thrive and produce healthy crops; however, they can easily get diseases and infections due to excess moisture. The key to growing healthy crops is to provide them with adequate water.

Please continue reading for tips on detecting overwatering in your onion plants and how to keep them healthy.

Why Overwatering is Harmful

Overwatering your onions could result in rotten bulbs or poor harvests. The onion bulb and roots will rot if the plant cannot completely dry out. Once rot has taken hold, you cannot salvage your onion plants.

Another consequence is a fungal infection, which can infect damaged onion plants. Fungi thrive in constantly moist soil, plant debris, and weed roots. They can also spread to other plants and survive in the ground for many years. 

If you notice signs of overwatering in your onion bed, take action right away. 

onion plants planted in brown wet soil

Signs and Symptoms

Soggy Soil

Soggy soil suggests that the soil did not have enough time to dry between waterings. The roots suffer when there is excess water and a lack of oxygen in the soil.

Check the soil’s moisture level before watering if the surface appears wet. If your finger comes out damp or with dirt adhering to it, you should wait longer before watering again.

Yellowing Leaves

When something inhibits your plant’s development, it can affect nutrient availability. Yellow leaves suggest suffocated roots, which is likely due to overwatering. 

In this case, it affects chlorophyll, the pigment responsible for the plant’s green color. As a result, your green onions can become yellow or brown at the tips.

spring onions in the farm

Unhealthy Foliage

Another sign of overwatering is the plant’s health deterioration, which manifests in the leaves. When the roots do not get enough air or oxygen because of the excess water, they drown and start to rot. Rotting roots make it harder for the plant to obtain the proper nutrients, reducing its vitality.

How to Fix It

At least two inches of water should be applied to onion plants weekly. Water them only once a week unless it is really hot outside, and make sure to keep the soil moist but not saturated. Stop watering your onion plant as soon as you notice signs of overwatering. Wait until the leaves start to look healthy again before you continue watering.

If rain is anticipated, use plant covers to prevent further overwatering in the next few days. Additionally, you could loosely cover the plant with straw to absorb excess water and keep weeds at bay. 

Once the rot occurs, there is no saving your onion plant. You can reduce the chances of rot caused by excessive moisture. Make sure your onions are planted in well-draining soil and have enough space to breathe and dry out between watering.

growing spring onions in the garden
Carley Miller
Carley Miller is a horticultural expert at Bustling Nest. She previously owned a landscaping business for 25 years and worked at a local garden center for 10 years.
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