Why are my Corn Plant Leaves Turning Yellow?

Whether boiled in a pot on the stove, grilled in their husks on the barbecue, or canned and jarred for later use, there’s nothing that brings to mind the taste of summer quite like fresh corn on the cob. Corn plants are hearty, resilient, and relatively easy to grow, making them a favorite of container gardeners everywhere. However, the last time you went to check up on your garden, you may have noticed some troubling yellow spots on your corn plants.

If you want a complete guide on growing you own corn plant at home or more Infos on how to avoid disease and tips on how to care for your corn plant, then you can check out my guide on growing corn plants at home right here.

So why are my Corn Plant Leaves Turning Yellow? To make it short, here are the most common reasons in one look. Underwatering, nitrogen deficiency, cool weather, pests, nutrient deficiencies, and disease.

Under Watering

Like all vegetable crops, corn plants need ample water.

Corn is a heavy feeder, and if it is under-watered and left exposed to heavy sun, its leaves can burn, resulting in an unpleasant yellowish-brown color.

To prevent this, make sure you water your corn plants every other day or three to four days per week.

For optimal results, spread woodchips, newspapers, dried grass cuttings, or your mulch of choice on the surface of your soil to retain moisture, and make sure to select a container with enough drainage holes to allow for adequate circulation.

In addition to keeping your leaves looking healthy, ample water actually adds to the sweetness and juiciness of your corn, so it’s a win-win situation!

Nitrogen Deficiency

Soil fertility is crucial for growing robust and high-yielding corn crops, and yellow leaves on your plants may well be the result of a nutrient deficiency in your potting soil.

If this is the case, your corn plants are likely suffering from a nitrogen deficiency: the reason your leaves are turning yellow is because younger and healthier leaves are robbing them of their nitrogen to make chlorophyll and to continue growing.

What can you do? Well, you can add a high nitrogen fertilizer to compensate for the deficiency! This will instantly feed your plants and add to soil fertility.

Be vigilant, however, especially if your corn plants are seedlings or young transplants, because so-called “hot” fertilizers can “burn” plants if they are used undiluted: for this reason, it’s a good idea to mix or cut your nitrogen fertilizer with potting soil or sand.

Another neat organic trick for those feeling adventurous is to plant peas in the same container as your corn plants: peas naturally affix nitrogen from the air, enriching the corn, while the corn serves as a natural trellis for the peas.

It is amazing to witness such natural cooperation in your very own garden! And you get to eat some delicious peas, to boot.

Cool Weather

Cool weather, complemented by excessive rain or shade, may be responsible for those nasty yellow leaves troubling your corn plants.

If the soil is too wet and cold, the corn has difficulty accessing the nutrients embedded in the soil; if the growing area is too shady, the plants will be deprived of crucial vitamins and heat from the sun.

Container gardeners have an advantage over traditional growers in that they have better flexibility and control over the conditions of their plants.

If those nasty leaves persist, try to move your corn plants to an area with more heat and light and better air circulation.

Remember that gardening requires trial and error–don’t get discouraged!

Pests

Pests are, well, a pest. Unfortunately, insects and pests such as nematodes, earworms, and aphids do sometimes afflict corn plants as they do other vegetable plants.

The best way to control pests is preventative: scour the stalks and leaves for critters and remove immediately if you see them; remove weeds, long grass, and debris from the surrounding area; and ensure you buy your seeds or transplants from vetted, non-contaminated sources.

There are a variety of organic and chemical pesticides available on the market for container gardeners, but the route you may decide to choose for pest control will depend on your budget, ecological practices, and other personal and external factors.

Other Nutrient Deficiencies

Although they are less prevalent than nitrogen deficiency, a shortage of other nutrients in your soil could be resulting in those stubborn yellow leaves.

These include, but are not limited to, potassium, magnesium, sulfur, copper, manganese, and zinc.

Each nutrient deficiency has certain distinctive signs: for instance, “burned” yellow streaks afflicting the lower leaves of the plant, which then turn to brown rot, are a symptom of potassium deficiency, while the appearance of a light yellowish stripe on the leaf base or rib signal the beginnings of zinc deficiency.

If you are having trouble identifying any specific signs associated with particular deficiencies, you might want to try taking a soil test.

Soil tests are cost-effective and easy, and they will inform you about the pH level of your soil, particular nutrient deficiencies, and will allow you to asses the overall health of your soil.

Plus, they’re a fun teachable moment for friends and family to dabble in some chemistry!

Disease

You’ve tried giving your corn plants more water; you’ve added nitrogen-rich fertilizer to your potting soil mix; you’ve gotten rid of any potential pests; you’ve moved your plants away from the shade and into the sun; and you’ve tested for nutrient deficiencies and pH abnormalities–no luck.

Unfortunately, if all else fails, and the yellowing is spreading and getting worse, turning to blight and rot, your corn plants may be infected with a disease.

In such an event, the best bet is to dispose of the corn plants, the contaminated potting soil, and any organic matter nearby to ensure the disease doesn’t spread to the rest of your garden.

You will also want to sterilize any tools and accessories employed in the job.

It is disappointing when plants don’t pan out but remember: if at first, you do not succeed, try again!

Good luck out there green thumbs!