Corn plants, Dracaena fragrans, are very popular tropical house plants due to their incredible air purification skills, long lifespan, and beautiful crown of foliage. In the right conditions and enough space, these hardy plants can grow up to 15 feet tall!
But, if you see your corn plant starting to yellow, you should quickly determine the cause, before it rapidly becomes unhealthy and dies.
In the article that follows, I’ll be explaining why yellowing leaf issues occur and how to save your corn plant when these problems arise.
Why Do Corn Plant Leaves Turn Yellow
The untimely yellowing of leaves due to environmental factors is called chlorosis. The condition disturbs the plant’s chloroplasts which are responsible for photosynthesis and makes the leaf green color.
When the photosynthetic process of a plant is interrupted, the plant losses its pigment and turns pale or yellow.
What Causes Corn Plants Leaves to Turn Yellow
Several environmental factors can naturally cause chlorosis, including problems with soil moisture, nutrient deficiencies, excessive sun exposure, pests, and diseases. Here’s a look at some common symptoms in close detail.
Corn Plant Leaves Turning Yellow and Falling Off in Summer
Nutrient deficiencies such as nitrogen will show signs of stunted growth, severe wilting, and the yellowing of the entire leaf surface starting with the older, lower leaves first. This can lead to unfortunate leaf drops during productive summer months.
If temperatures frequently drop below 60 degrees Fahrenheit, corn plants are likely to experience a serious injury that creates yellowing dead spots on the leaves followed by a massive leaf drop event.
The lower leaves of your corn plant will naturally senesce and turn yellow every 2 to 3 years, so it’s just part of the natural regenerative process of a plant to shed its older leaves.
Corn Plant Leaves Yellowing with Brown Patches
When yellowing leaves appear with brown edges, it is usually a sign of severe underwatering or extremely low relative humidity levels.
Too much direct sunlight or too much intensity of light will cause corn plant leaves to yellow, curl, and brown on the edges.
Yellow leaves with brown edges are also a sign of over-fertilization of the soil or fertilizer burn on the leaves.
Corn Plant leaves with Yellow Tips or Edges
Yellowing tips on your corn plants most often indicate damage from fluorinated and chlorinated water.
Yellowing of the leaf edges of corn plants can indicate there is a lack of potassium in the soil.
Corn Plant Leaves with Yellow Veins
A high pH, often caused by over-fertilization, will cause nutrients such as iron to become deficient, which causes interveinal chlorosis in corn plants on their youngest leaves.
Magnesium is an essential nutrient that is missing from the soil and will cause the foliage to get yellow interveinal striping on its lowest leaves.
Eventually, the deficiency gives the leaves round dead spots and reddish-purple leaf tips.
Corn Plant Leaves are Yellow and Drooping
The most likely cause of yellow and drooping leaves on corn plants is improper soil moisture. Over and under-watering can cause leaf chlorosis, wilting, root rot, and eventual plant death.
Corn Plant Leaves Turned Yellow with Brown Spots
Fungal diseases and pest predation are often the culprits of yellowing leaves and brown spots.
Tip Blight Disease, or anthracnose, will cause corn plant leaves to turn yellow, leaf edges to brown, and dark spots with yellow halos to form all over the foliage. If left untreated, the corn plant will die.
Corn Plant Leaves with Yellow Spots
Tiny yellow dots on the foliage of your corn plant are most likely caused by a spider mite infestation. If the population is allowed to grow, a fine webbing will eventually encase the entire plant and it will die.
Treating and Preventing Yellowing Corn Plant Leaves
Corn plant leaf chlorosis is the first indication of a potentially serious issue and should be treated quickly to prevent any further issues.
Here’s what to do to treat and prevent yellowing leaves in corn plants:
Watering Problems – Over and Underwatering
Use containers with drainage holes and remove any water in the saucer that will move through osmosis into the soil, creating a saturated and toxic environment inconducive to root growth.
Water on a timely schedule every 7 to 10 days during the growing season. During times of winter dormancy, decrease watering frequency to once every 2 – 3 weeks, so that the soil doesn’t remain saturated when growth has significantly reduced or stopped.
If you suspect the soil is becoming frequently saturated, then transplant your corn plant into potting soil with better drainage.
Use a well-draining soil mix with the following ratio:
- 1 part Coco Coir
- 1 Part Perlite
- 1 part Vermiculite
- 1 Part Worm Castings
Using Unfiltered Tap Water
Corn plants are sensitive to chemicals and heavy metals in tap water. Chlorine, chloramine, fluoride, and other chemicals or minerals build up in the soil over time and lead to leaves turning brown and crispy at the edges. This is often accompanied by a yellow halo around the outer edge of dry brown dead sections of the leaf.
There are certain plants that I only ever water using rainwater, which I collect in a rain barrel. Calathea is especially sensitive to the tap water in my region, but Dracaena is also renowned for its sensitivity to tap water too. When symptoms appear, flush your corn plant with rainwater or filtered water 3 – 4 times to remove the high concentration of chemicals in the soil, then supplement with a liquid fertilizer.
If over-fertilization occurs, flush the soil with water until it floods, repeat several times for 1 week. Refrain from using additional liquid fertilizer supplements, and instead, add 1 inch of top dress that contains 50% organic potting soil and 50% worm castings every 6 months.
How to Fertilize a Corn Plant
Corn plants are more likely to lack nitrogen than any other nutrient because nitrogen is often removed from the soil through leaching and heavy watering.
If chlorosis from nitrogen deficiencies occurs, then increase your supplemental top dress application to once per month.
Potassium deficiencies are likely to occur after times of underwatering and can be fixed by using a liquid fertilizer formula with an N-P-K ratio of 3-1-2 or 3-1-3 and sticking to a watering schedule.
Since corn plants are sensitive to salt, fertilize with a top dress of worm castings instead of adding Epsom salt regiments, which is the typical prescription for magnesium deficiencies.
Corn plants need a soil pH of 6 to 6.5.
Check the soil with a handheld pH meter and adjust accordingly with specific pH up or down formulas available at your local grow store.
Excessive Sunlight Exposure
Corn plants are tropical understory species that prefer filtered, bright sunlight. They will get severely sunburnt if left in the sun but will return to normal if promptly relocated to a more suitable location with 6 – 8 hours of filtered sunlight.
Relocate your corn plant to a spot that has 63 – 73% shade, trim any brown leaves on your corn plant, and feed a supplemental fertilizer to help it recover.
Rapid Temperature Fluctuations or Low Humidity
All 120 varieties of Dracaenas prefer temperatures between 70 – 80 degrees Fahrenheit.
Place them in a warm draft-free room and keep the relative humidity between 60 – 100% by adding a heated humidifier.
Spider mites, scales, and other common houseplant pests can be treated by applying all-natural essential oil sprays that contain neem, lemongrass, and lavender.
Periodically wiping the leaves and isolating new plants from greenhouses helps prevent new infestations.
Tip Blight Disease, or anthracnose, is best treated with a blight-specific fungicide or prevented with all-natural essential oil sprays. Always use as directed.
FAQ Corn Plant with Yellow Leaves
Will yellowing leaves turn green again?
Generally, yellowing leaves will not turn green again. It is best to cut off any dying leaves before they attract pests that can infect your corn plant with fungi infestations and bacterial diseases.
- The University of Florida IFAS Extension Cultural Guidelines for Commercial Production of Interiorscape Dracaena
- Department of Plant Pathology Tip blight disease of Dracaena fragrance caused by Lasiodiplodia the bromate (Botryosphaeriaceae), from India
Ben's horticultural interest grew when graduating from Hertfordshire University in 1997. Having contributed to numerous publications including Better Homes & Gardens, Garden Design Magazine, and The English Garden. He is also the author of Propagating Houseplants Made Easy.