Corn leaves turning yellow

Yellowing Corn Leaves: Why Corn Plant Leaves Turn Yellow

Corn is one of the most popular crops to grow in the home garden. Not only is it delicious, but it is impressive when all goes well. Since this life we lead is unpredictable even with the best laid plans, you may find that your corn plants have yellowing corn leaves. What causes corn plant leaves to turn yellow and how do you go about treating yellowing corn plants?

Help, My Corn Plant is Turning Yellow!

We’ve been growing corn for the last few years with varying success. I chalked it up to our generally cool summers and the fact that the huge pine trees in the backyard are blocking most of our sun in the veggie garden. So, last year we grew corn in containers on the patio with full sun exposure. Bingo! Of course, we decided to grow our corn in containers again this year. Everything was going swimmingly until almost overnight we noticed the corn leaves were turning yellow.

So I turned to the handy dandy internet to find out why my corn plant was turning yellow and learned that there were a few possibilities.

First of all, corn is one of the heaviest feeders in the garden. Yellowing corn leaves are most probably an indicator that the crop is deficient in some nutrient, usually nitrogen. Corn is a grass and grass thrives on nitrogen. The plant moves nitrogen up the stalk so a nitrogen deficiency manifests itself as corn leaves turning yellow at the base of the plant. A soil test can help you determine if your plants are low in nitrogen. The solution is to side dress with a high nitrogen fertilizer.

Cool weather can also make corn plant leaves turn yellow. Again, this is due to a lack of nitrogen. When soil is cool and wet, the corn has trouble absorbing nitrogen from the soil. So this doesn’t mean there is no nitrogen in the soil, simply that the poor plants are too chilled to efficiently take up enough. The good news is that if cool weather is the culprit the plants will grow out of this yellowing as the weather warms up.

Insufficient water will also result in yellow leaves. Corn needs a lot of water, at least once weekly and depending upon the weather up to every day. This was a likely case for our corn yellowing, given that is was container grown and received full sun for most of the day.

Disease, such as maize dwarf mosaic virus, can also cause yellowing of leaves combined with stunted growth. This disease is spread by aphids lurking in nearby weeds, such as Johnson grass. Once the plants are infected, it’s over. Remove and destroy the canes and sterilize any tools or work gloves that have come into contact with them.

Nematodes also can contribute to yellowing corn leaves. Again, this has to do with a lack of nutrients. The nematodes, microscopic roundworms, live in the soil and attach themselves to the plant’s roots, preventing it from absorbing enough nutrients.

Treating Yellowing Corn Plants

If your soil test indicates a lack of nitrogen, side dress with a high nitrogen fertilizer when the plants have 8-10 leaves and again when the first silk appears.

Keep the corn watered on a regular basis. Again, at least once a week and up to once per day to keep the soil moist one inch below the surface. We had an extremely, unusually warm summer with temps into the 90’s, so we even watered twice a day since our corn was in containers. Use soaker hoses and mulch the soil with 2 inches of grass clippings, straw, cardboard or newspaper to reduce evaporation. Prior to planting, amend the soil with plenty of compost and peat moss.

Keep the area around the corn free of weeds to deter insects and disease. Rotate your corn crop if nematodes seem to be the problem. If nematodes seem to be in all areas of the garden, you may need to solarize. This involves covering the garden with clear plastic during the 4-8 hottest weeks of summer. Rather a bummer that you won’t have a garden, but this kills the nematodes as well as weeds and soil pathogens.

Why are my corn plant’s leaves turning yellow?

Backstory:

I picked up my Corn Plant about a month ago (January 21st) from a local nursery. The plant had just been watered and the lady told me that I will likely have to water it once a week. After a week passed the surface of the soil was still damp to the touch so I let it go a few more days before I gave it a thorough watering.

Please note that this is my first house plant so I am learning as I go. When checking for moisture content in the soil I was mostly looking at the surface or slightly below (half and inch or so). I have since read that waiting until the soil is drier a little deeper would be better. The other thing I did (that I have since read wasn’t a great idea) was to use tap water instead of purified water. The water in my area comes mostly from the ground and has a high mineral content. Worried this might have had an affect on the plant.

A few days ago I noticed some of the leaves turning yellow on the small stalk. They have since started to turn brown at the base. The centre of the sprout is also brown where new leaves should be coming out. The other sprout on the same stalk seems to be doing just fine.

I have yet to water the plant again as the soil is still damp below the surface. All of the rest of the sprouts are looking really healthy and green.

Questions

Any ideas why the leaves are turning yellow and brown at the base?

Is this a result of overwatering, mineral content in the water or something else?

Should I be trimming this sprout before it affects the rest of the plant?

Any advice will be greatly appreciated.

Thanks!

Corn

Nitrogen

When young corn leaves turn pale yellow or light green, have thin stalks and are slow to come to flower, it might be a nitrogen deficiency. The older plants exhibit a “V – shaped” yellowing at the tips of leaves and older leaves show symptoms first, with these tips and mid-ribs eventually senescing.

Potassium

Light green or streaked with yellow leaves can indicate a potassium deficiency. This yellowing or “scorching” of the leaf margins, more common on the lower leaves, turns to necrosis, and in older plants, leaf tips and margins turn brown.

Magnesium

Older leaves which develop a yellow/white interveinal chlorosis are often a symptom of magnesium deficiency.

Sulphur

Sulphur deficient plants are stunted with pale green to yellow leaves. Leaves commonly take on a striped appearance with light yellow coloured veins. Lower leaves can remain green, in contrast to nitrogen deficiency, where they are the first to chlorose.

If corn plant growth is reduced and there is a characteristic chlorosis between the veins of the younger, upper leaves, the plant most probably has an iron deficiency.

Zinc

The appearance of a pale yellowish green chlorotic stripe near the leaf base – or on each side of the mid rib are the first signs of a zinc deficiency. Silking, tasseling and maturity are delayed, leading to reduced yield. Zinc deficiency is increased on calcareous soils with high pH and high levels of phosphorus. Of all the micronutrients, zinc is most likely to be needed in corn, with deficiencies most commonly detected between the V2 to V8 stage.

Copper

If the plant has a copper deficiency, the young leaves are yellow or light green and at later stages of growth these leaves curl and the leaf tips wilt, turn white-grey and die.

Manganese

Under severe manganese deficiencies, young and medium formed leaves have uniform, white-yellow stripes in the midsection of the leaf. The stripes become necrotic with the dead tissue falling out of the leaf. Symptoms are similar to those for iron, and leaf tissue analysis is needed to confirm the deficiency. Manganese deficiency is most likely to appear on highly weathered tropical soils, particularly well aerated soils.

Plants that Resemble Corn Stalks

House Plants That Resemble Corn

One of the most well-known plants that resemble corn stalk is the Dracaena fragrans massangeana, or more simply, the corn plant.

The Dracaena plant does not produce an actual stalk of corn, nor does it tassel or produce ears. Instead, the leaves look like the leaves of a healthy corn stalk. The plant itself has one thick stem that resembles a tree branch. The leaves typically grow at the top of the stem.

Corn plants are easy to grow and exceptionally hardy, only requiring regular watering and indirect sunlight to thrive.

Tip: Although people plant this variety to enjoy the bright green foliage, you may even get an occasional bloom!

Outdoor Plants That Resemble Corn

There are only a few indoor plants that look like corn, but outdoors is another story! Have you ever wondered where the bristles of your favorite broom come from? The answer is from a plant called broomcorn. Although the plant does not produce leaves that look like corn, the bulk of this plant looks like corn tassels!

Additionally, there is the grain sorghum, which looks like a corn stalk but is much shorter. The top of the plant, called a head, can be yellow, red, or even a striking bronze color.

Millet is also a grain-like plant whose leaves resemble those of a corn plant. If you did not plant millet but find it growing in your yard, it likely comes from seed falling from your bird feeder!

Weeds That Look Like Corn

There are other corn-like plants that you can easily find growing in your garden or lawn, but these are not plants you can get excited about. Instead, they are weeds, and you should eradicate them as quickly as possible. Some of the more noxious varieties include:

  • Johnson Grass
  • Quackgrass
  • Giant Reed
  • Crabgrass

If you notice any of these weeds in your garden or lawn, you should employ a reliable method of organic weed control in addition to pulling the plants by hand. Be sure to remove the plants before you notice seed heads appearing, as the seeds spread very quickly.

In short, if you notice anything that looks like corn in an area where corn should not be growing, identify it as soon as possible. By doing so, you may be able to prevent weeds from overtaking your land.

Plants of the Dracaena family are very easy houseplants to care for, but on occasion they present yellow leaves, a telling symptom of overwatering.

Here’s how to double-check that your plant has been getting too much water and care for it so the leaves turn back green again.

  • Shown here is an overwatered Dracaena massangeana.

Dracaena leaves turn yellow

Overwatering is the most common cause for Dracaena leaves to turn yellow.

  • Leaves of the dracaena lose their green color and turn pale.
  • They lose their crisp, semi-rigid bearing and start feeling soft and limp.
  • Instead of reaching for the sky, they droop down and sag towards the floor.
  • Yellow-brown spots develop at the center and edges of leaves which die off and dry up.
  • Younger, topmost dracaena leaves are less affected than older, lower leaves.
  • If you lift the plant out of its pot, roots are swollen, translucent and mushy or soft to the touch. These are the first stages of root rot.

Usually these telling signs develop over the course of a couple weeks to a month.

Note that tips of dracaena leaves turning brown is another problem unrelated to overwatering: plant necrosis due to fluoride and salts in water.

How to check for overwatering

Finger-check for moisture

First of all, you should check with your finger how wet the soil feels.

  • Soggy soil that smells moldy or foul is a clear indication.
  • Sometimes the first inch of soil seems fine but below that it’s very wet.
  • Soil gives a slimy sensation when you rub your fingers together.
  • If you use plant mulch or organic material, it tends to turn blackish in case of excess water (twigs and wood that never dry turn dark colors.

In some cases, you can even see that plants send roots up out of the soil like in the case of this rotting sunpatiens.

Check the underside of the pot

  • There should be a draining hole in the container so that excess water can flow out.
  • Sometimes roots have grown through the holes and thickened so much that the drainage holes are “clogged”.
  • Usually pots rest upon a saucer to collect excess water. In case of overwatering, this excess water remains in the saucer or pot-holder and is never thrown out.

Wrong watering schedule

  • Perhaps you water the plant every day or couple days.
  • Perhaps too many persons are involved and everyone waters the plant too often.

How to save a dracaena with yellowing leaves

Follow these simple steps to save your yellowing dracaena:

  • Stop watering daily. Make watering your dracaena a weekly task, no less. Check with other persons so that it isn’t done redundantly. Use a watering planner or simply a small calendar with marks on the date to show it’s been watered.
  • Check for holes at the bottom of the pot for optimum drainage. If it’s a plastic pot, sometimes the holes aren’t drilled yet or cut out. Use a drill or cutter and make at least three holes. If it’s a terra cotta or clay pot, use a ceramic drill bit for that, or simply protect the hole from clogging with a piece of mesh wire.
  • Change the soil mix of your dracaena to something that drains much better. You can use river sand for a third, potting soil mix for a third, and garden soil. River sand isn’t salty. If you only have sea sand at hand, set it out in a thin-meshed sieve for a couple months and rainwater will wash the salts out. Don’t add any perlite or hydrogel crystals.
  • Remove rotting roots that may already have started turning mushy. These won’t recover and will be an open invitation for root rot fungus and the like. You can leave yellowed leaves until you’re certain they’re dead. Sometimes pale leaves can recover.
  • Layer gravel or clay pebbles at the bottom of the pot over a good two inches (5 cm).
  • Remove the pot-holder and ensure that excess water is quickly thrown out. After watering the plant, promptly empty the saucer under the pot from any water that may have collected in it. A good solution is to spread gravel or clay pebbles in the saucer and rest the pot atop it. Not only will this keep excess water from touching the dracaena pot, it will also help the excess water evaporate, thus increasing air moisture which is good for the plant.

Learn more about Dracaena water needs

The Dracaena plant evolved in a context of arid droughts interspersed with flash floods and heavy rain. This led the plant to develop specific qualities that make dracaena resistant to underwatering.

However, these tweaks that nature gifted Dracaena for dry climates become a huge disadvantage when the plant sits in a constantly moist environment like marshes, swamps, or overwatered pots.

A study for Dracaena marginata has shown that the optimal watering schedule for dracaena is every 5 to 7 days.

A good way to water this plant is the “drench & drip-dry” method.

  • Partly fill a sink or large pail with water.
  • Place the pot in the sink or large pail. Water should reach soil level for the pot.
  • Let the pot sit in water for about 10 minutes.
  • Lift the pot out and rest it atop a grill or similar so that all excess water can drain out.
  • When the dripping has stopped, return the plant to its place. Voilà!

Only water when the soil has turned completely dry. To check, stick your finger down to a depth of 2-3 inches (5-8 cm). It should come out dusty and dry. If there’s even just a little moisture left, don’t water yet.

Winter watering of Dracaena:

Winter triggers dormancy in plants of the Dracaena family. The same rules as above apply, except that it may take up to a month for the soil to dry from the previous watering. Water every 15 to 30 days, no need to water weekly when the plant is in this rest phase.

Smart tip about watering your dracaena

Best is to use rain water that is collected as runoff from rain or from trees. Set basins under the drip line of trees or under the roof gutter spout. This water is free from municipal water additives which eliminates risk of leaf tip necrosis. Additionally, it’s loaded with nutrients from lichen, moss, bark, leaves and animal life that collect in dust that the rainwater picks up.

Read also

  • How to care for your Dracaena houseplant
  • Why Dracaena can survive underwatering
  • Dracaena marginata and Dracaena massangeana, the two most common Dracaena varieties.

Credits for images shared to Nature & Garden (all edits by Gaspard Lorthiois):
Many thanks to Phishmcz for the image

Dracaena Fragrans (Corn Plant)

Corn Plant Care Guide

Light

Most of those in the Dracaena genus including the Corn Plant do best in light shade or gentle filtered sunlight. The leaves will scorch if too bright and if it’s too dark the new leaves will be quite small and the stripe(s) may look quite different to those found on the older ones.

Watering

These plants benefit from a little “drying time” between waterings. So water well and then wait for the top inch of the soil to dry out before watering again. If your Corn Plant is placed in a good spot with reasonable light and warm temperatures, (excluding Winter) you can keep the soil moist at all times.

Regardless of your placement, in Winter reduce the watering like you would for almost all houseplants, but the soil shouldn’t be allowed to dry out completely.

Humidity

Reasonable humidity is required to prevent blemishes on the Corn Plant’s leaves. Misting is a good way to achieve this as well as helping to keep the leaves dust free.

Feeding

Regular feeding in Spring and Summer is recommended. You don’t need to feed in Winter or feed newly repotted plants.

Temperature

The Ideal growth range is between 16°C – 24°C / 60°F – 75°F. No lower than 10°C / 50°F and avoid even light frosts at all costs.

Repotting

You only need to really repot every two or three years. But there is no harm in doing it more frequently if you feel it’s needed and of course if you have the space and a big enough pot for it.

Propagation

There are three main ways to propagate and typically you can do all three methods at once to create multiple plants. In time the canes will become leggy as the leaf area shifts higher and higher up the plant which means you can:

  • Remove the crown and pot it up in potting compost to start a new plant, use a rooting hormone and to increase your chances further, provide bottom heat.
    Tip – if you can’t provide bottom heat, only attempt this in Summer and keep it warm.
  • Once the crown has been removed you can cut the remaining cane back to about half the original length (or more or less depending what you are trying to achieve visually). New growths should eventually form at the cut edge.
    Tip – because several new growths can form at the cut, this is how you can create a multi-caned plant.
  • Assuming you’ve done both things above, you will have a piece of cane left which can be cut into bits and used to create a “Ti Tree”. Allow to dry slightly before sticking straight up in potting compost. Keep the soil warm and moist.
    Tip – the pieces need to face “up” in the direction they were growing when part of the parent plant so you may want to mark the cane before you get started.

Speed of Growth

It’s quite slow growing, but there is enough new growth to notice its “alive” and draw attention to itself (that might sound wacky, but seasoned indoor plant owners will know what we mean).

Height / Spread

This depends on how tall your ceiling is! To be fair, while natively it could reach 15m / 49ft or more, indoors you will probably run out of large enough pots to allow the plant to ever reach such a size, so expect it to only reach 2m / 6ft after many years.

Flowers

You rarely find flowers on indoor plants from the Dracaena genus, D. fragrans though is the exception. Pay attention when we say the flowers are still not frequent enough to call their appearance “common”, but they do occur occasionally if the plant is mature and being treated well.

Sprays of small numerous white flowers will come shooting out of the crown and they have a highly fragrant almost sickly sweet scent.

Are Corn Plants Poisonous?

The sap found within the leaves and stems do have small levels of a toxic substance that, while unlikely to be fatal, can cause irritation in people and pets when eaten.

Anything else?

Don’t forget to clean the leaves when they get dusty and if your Corn Plant gets too big… Don’t be afraid to cut it down to size and start again.

Corn Plant Problems

No Flowers

In most cases if you end up with flowers you are very lucky. You’ll need a mature, well cared for plant that is basically happy. Even then, the flowering is unpredictable and does not occur every year or with any sort of pattern.

Yellow lower leaves / leaf drop

All Dracaenas including the Corn Plant are False Palms, with a crown of leaves sitting at the top of their stems, new growth forms at the very tips of these stems and the older leaves at the bottom of the crown will gradually yellow and fall. This happens quite often, but providing new leaves are forming as well it’s normal.

Leaves with brown spots

Normally this is a sign of underwatering. You must try to keep the soil moist at all times where possible because although the plant will cope with periods of occasional dryness, if it’s prolonged then damage will result.

If the brown spots are are more “blotches” than dots, it’s caused by overwatering. The plant in the photo shows brown spots as well as the next problem:

Bleached dry leaves

Scorched leaves caused by too much sun. Move to a more shadier area.

Leaves have brown tips and yellow edges

This is often caused by dry air or cold draughts. Increase humidity and keep warmer.

Soggy Cane / Stem

Too much water over a long period, usually when it’s also cold. If this happens then your Dracaena is probably already on its way out and can’t be saved in its present form. Although if any parts of the stem feel firm, or the leaf crown is intact you could try and propagate.

About the Author

Tom Knight

Over the last 20 years Tom has successfully owned hundreds of houseplants and is always happy to share knowledge and lend his horticulture skills to those in need. He is the main content writer for the Ourhouseplants Team.

Also on Ourhouseplants.com

Credit for Dracaena fragrans flowers – Article / Gallery – Ripepette
Credit for Dracaena fragrans ‘massangeana’ – Article / Gallery – KENPEI

Community Comments

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Are the yellow leaves on my Massangeana due to root rot?

Could be two things:

Spider mites like Dracena Massangea that are located in dry conditions like the inside of your home or an office. (Dry is relative humidity < 40% for tropicals). They can be easily detected by examining the underside of the leaf in good light. You could see small white specks. A magnifying glass will allow a definitive diagnosis. Severe cases have webs usually located in the axils of the newest growth.

A solution of dish soap and water applied by running a cloth over the underside of all the leaves at about 6 day intervals for 3 or 4 repetitions should control or eliminate them.

The most common cause is overwatering and consequent root rot. This does not look like the case here.

EDIT Root rot starts from the soil and works upward. New stalks can continue to look green for a while until the last of the available water is used. The final symptom is often papery dry leaves at the point of newest growth. A good test for root rot is to grip the trunk and see if it the bark is firm or has softer hollow areas that run vertically. As root rot progress vertical sections of the trunk stop moving water up.

However the last cause is competition amongst the trunks. These trees are usually grown in Costa Rica then cut down with chain saws and shipped like logs to Florida for finishing. The smaller trunks can be out competed by the larger ones. Here, the only solution is to move the plant to a sunnier location and rotate the pot once a week to ensure even lighting.

Your last question is about rooting cuttings. This is ridiculously easy for a healthy plant in good light. Cut a section of new stalk off that has at least 3 or 4 inches of bare stem and place in water in good light.

A plant with rot or mites is not going to have cuttings that do much better so you need to diagnose the primary issue first before taking cuttings.

In my ten years as an interior landscaper I noticed the most long lived massangea were the ones planted in a clay soil. This is totally contrary to what you would expect but an interesting idea if you have clay soil and a healthy plant. The dangers of microbes and “bugs” in soil from outside are exaggerated in my opinion.

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