Cantaloupe leaves turning yellow indicates something wrong with your plant. It may be related to its living conditions, or it could be due to a foreign element.
The most common cause of yellowing cantaloupe leaves is overwatering. Other causes include underwatering, manganese toxicity or deficiency, pests, disease, and poor living conditions.
In this article, we will discuss the causes of yellowing cantaloupe leaves and how to remedy each one.
Why are my cantaloupe leaves turning yellow?
Overwatering
The most common cause of yellowing cantaloupe leaves is overwatering. When the plant’s soil is saturated with water, it cannot receive as much oxygen as it needs. The roots will become ineffective at absorbing water and nutrients from the soil, and thus the plant’s ability to produce chlorophyll is impaired. Chlorophyll gives plant leaves their green color, so no chlorophyll production means discoloration of leaves. The leaves will turn pale and yellow.
Overwatering also makes your plant more susceptible to disease and pests.
When you notice your cantaloupe’s leaves turning yellow, it is most probably due to overwatering, so take this as a sign that your watering schedule needs to change. Remember that cantaloupe plants need one to two inches of water every week,especially during the first stages of fruiting.
The moment you notice yellowing in the leaves, reduce the frequency of watering. You can either lengthen the time between watering or reduce the volume of water you use each time.
Underwatering
As mentioned above, cantaloupe plants need one to two inches of water every week. As much as cantaloupes do not like to be overwatered, you should also make sure you are not underwatering your plant.
Plants need water to be able to effectively transport nutrients from the soil to the plant. Even if the plant is in nutrient-rich soil, it will still suffer if it is not being watered and the soil is dry, because nutrients are gathered in the water which is absorbed by the roots of the plant.
The plant will turn yellow due to lack of nutrition and water. In hot weather, even if you water your plant it can become underwatered, because the weather makes the water evaporate faster and the plant’s roots may not be able to keep up.
Check the soil around your plant before watering. If the soil is dry, water the plant, but if the soil is still damp, wait a few days and check the soil again.
Manganese toxicity and deficiency
Manganese toxicity in cantaloupe plants occurs when the soil pH gets anywhere below 5.4. The acidity increases the availability of manganese in the soil, so the plant tends to absorb more manganese than required. These elevated manganese levels are toxic to cantaloupe plants, which only need a very small amount of manganese. Some fertilizers contain manganese, so if you suspect manganese toxicity to be the cause of the yellowing leaves, stop using your fertilizer and test your soil’s pH – it should be neutral or 6.0. If the pH is lower than 5.4, add dolomite or lime to the soil to make it less acidic.
Conversely, when the plant does not get enough manganese, it can suffer chlorosis and the leaves will also turn yellow. If you think the plant has a manganese deficiency, apply fertilizer with manganese to correct this.
Pests
Whiteflies are pests that can cause the leaves on a cantaloupe plant to turn yellow. They will suck on the plant’s sap and excrete honeydew that causes a black mold to grow. These conditions interfere with the process of photosynthesis, hence the yellowing of leaves. You can get rid of whiteflies by vacuuming them off and spraying the plant with biodegradable soap. Fortunately, both the honeydew and the mold can be washed off.
Spider mites
Spider mites are pests that can turn the leaves on a cantaloupe yellow and even brown, while the underside of the leaf is silvery-gray with yellow or red spots. These insects also drink the sap of the cantaloupe leaves. You can get rid of them by spraying the leaves with insecticidal soap or wiping them down with neem oil. You can prevent these bugs from attacking your plant by keeping the plant watered, because spider mites like to live in dry conditions.
Squash bugs
If your cantaloupe leaves are speckled with yellow flecks, it may have squash bugs. These yellow speckled leaves will eventually turn brown. Squash bugs are small brown bugs that can be removed easily from the leaf by picking them off. Unfortunately, picking them off the plant one by one is only effective if the infestation is small and has just started. Mulch can also be a protective cover for the squash bugs, so remove it while you are treating the infestation.
You can use diatomaceous earth or pyrethrin spray around the base of the plant to kill these bugs.
Melon thrips
These long, yellow insects have a black line down their back. They will attack the cantaloupe leaves which will turn yellow, then brown, and drop off.
Disease
Cantaloupe plants are susceptible to several plant diseases, including the mosaic virus. This virus can cause the plant’s leaves to become small and distorted and turn a mottled yellow. If you suspect the mosaic virus, make sure you pull off any infected leaves and dispose of them properly so that none of your other plants are affected.
This virus is introduced to the plant by insects. When you are pruning the infected plant, make sure you disinfect the tools after each cut so that you do not contaminate other parts of the plant or a completely different plant. Wash your hands after touching the infected plant.
Downy mildew is another organism that causes yellow spots to appear on the cantaloupe leaves. The undersides of the leaf will appear fuzzy and gray. You can control the spread of downy mildew by removing plant debris from around the base of the plant.
Poor living conditions
Air pollution can cause cantaloupe leaves to turn yellow, especially the older leaves at the crown of the plant.
Fungicides and de-icing salt in the soil can also cause the leaves to yellow, but instead of those at the crown, the leaves at the bottom and along the margins are the ones that turn yellow.
Conclusion
Yellowing cantaloupe leaves can be indicative of a problem with the plant’s nutrient uptake or a factor in its surroundings such as weather, disease, or the environment.
The key to fixing the yellowing leaves on your cantaloupe plant is to correctly identify what caused the problem in the first place.
The most common causes of yellowing cantaloupe leaves are overwatering, underwatering, manganese toxicity or deficiency, pests, disease, and poor living conditions.
Image: istockphoto.com / Chadchai Krisadapong