Why Is My Corn So Small? Causes and Solutions

If you’ve ever grown your own corn plants, only to be disappointed by small ears of corn, then this article is for you. There are a number of reasons your corn plants or cobs might not be the swaggering size you’d hoped for. So we set out to answer the question: why is my corn so small? Let’s find out.

Small Corn - Why Is My Corn So Small

The most common reasons corn is small is due to a lack of soil nutrients, watering problems, compacted soil, as well as pests, and lack of pollination.

Armed with the right knowledge, you can create the right conditions for corn to flourish happily. 

Related: How To Grow Corn: A Beginners Guide To Growing Corn

Lack of nitrogen can cause small corn

Growing Corn - Why Is My Corn So Small

Corn needs feeding if it’s going to feed other people and nitrogen is its dinner of choice. If the soil is nutrient deficient, your corn is going to struggle to give you the yields you’re looking for resulting in small corn.

Why? Because corn requires nitrogen for amino acids, protein, and chlorophyll production. Which in turn is the key ingredient for successful photosynthesis. Without all of this, the corn plants’ ability to reproduce seed (tasty corn kernels for us) is going to be hampered.

Prepare your planting area with plenty of natural, aged compost. Or add organic fertilizer products such as these soybean or cottonseed meal.

The advantage of plant-based fertilizers rather than blood or bone-based products is that they’re less likely to attract animals to your yard. Though they do tend to be less nitrogen dense and slower releasing. So you may need to apply them in higher concentrations. Check the packet for instructions!

Watering problems cause small corn

Corn Growing in Dry Soil - Why Is My Corn So Small
Corn growing in dry soil

Despite their sometimes imposing height, corn plants actually have deceptively shallow roots. During dry periods corn crops can struggle to reach deep enough beneath the soil surface to tap into the water it needs. A lack of water can cause corn to be small and stunted.

For this reason, you need to make sure you’re watering corn regularly and keeping the soil moist. 

Watering corn plants 2-3 times a week during drier spells may be necessary to keep them from getting parched. This is particularly true as corn also prefers to be planted in open, sunny areas. Often leaving it more prone to the effects of drying out.

At the same time, over-watering or poor draining soil can lead to stunted or even diseased corn crops. Corn doesn’t do well in standing water or long periods of damp.

It can be a difficult balance for gardeners to strike. But the best way to grow a thriving crop of corn is to ensure the soil you’re planting in is cultivated, well-drained, and not compacted. 

This way you will be able to keep the soil moist and fertile, without risking it turning into a lake when a rain cloud passes through.

Compacted soil can cause small corn

As well as reducing the soil’s draining capacity, an overly compacted planting area can make it difficult for corn roots to establish themselves. Compacted soil can also restrict the uptake of nutrients and water.

Soil, and the plants that live in it, needs to breathe, and overly compacted soil can result in oxygen deficiency.

Try to make sure you’re planting in well-tilled, well-drained soil. Using a pitchfork or garden hoe to till and turn the earth roughly a foot (30 cm) down should give you a good starting point.

Prepping the earth in this way also gives you a chance to get nutrients into the bed before planting. So make sure when you’re tilling you throw some aged compost, manure, or natural fertilizer in there as well.

Pests can cause corn to be small

Worm Pests on Corn - Why Is My Corn So Small

Is something else eating your corn before you can? Corn earworm is just one hungry pest that likes to nibble on corn before we’ve had a chance to get our hands on it. It can appear as a brown-headed caterpillar. It finds its way into the central spiral of the corn and feeds on developing tassels.

Applying mineral oil or vegetable oil to the silk at the tip of the corn ear roughly 5 or 6 days after it has first emerged can help guard against this.  

Other bugs, such as mealybugs and aphids, can be guarded against by making sure you’re regularly clearing the area of decaying or fallen leaves. And by gently removing insects with water or a soap and water spray. Insecticidal soap or horticultural neem oil is also useful for managing these pests organically.

The sort of pests you encounter in your own garden is likely to depend on the season and region you’re in. As a general rule, the more varied your planting and the more biodiverse your garden, the more evenly distributed potential pests are likely to be. And the more effective the ecosystem is likely to prove in keeping them in check.

Wasps and other beneficial insects are nature’s natural insecticides. So making sure you have a garden that all critters love is a good way of ensuring no one pest takes over the whole garden!

Lack of pollination for corn plants

What if your corn is roughly as big as you expected, but there seem to be kernels missing? Leading to patchy corn ears that look like they might have been nibbled?

Missing corn kernels are usually because the corn hasn’t pollinated properly.

Unlike a lot of vegetable crops, corn relies on wind pollination. Each individual seed on the corn cob needs to be pollinated in order for it to develop. Pollen is passed from the male ‘tassels’ at the top of the corn to the individual silky strands attached to each kernel.

This is why it’s best to plant corn in blocks rather than in a single row. This will maximize cross-wind pollination and give each corn plant the best chance of getting pollen from its neighbor. It’s also why corn crops tend to take up more room than other crops. You may need a decent corn patch to give each corn plant the best chance of reproducing.

Leave about 12 inches (30cm) between each corn plant and try giving the stalks a gentle shake from time to time. This will help disperse the pollen in the corn plant and move things along!

Corn varieties and guarding against disease

Corn Growing - Why Is My Corn So Small

Corn comes, quite literally, in all shapes and sizes. And some dwarf corn varieties won’t necessarily need to grow tall in order to produce decent ears. If your corn plant isn’t reaching the dizzying heights you hoped for, it might be that it’s not genetically programmed to!

When picking a variety of corn to plant, think about the space you have. Including the height of crop your garden is able to deal with. Remember, tall corn means shade for other areas. As well as the climate you’re growing your corn in.

You can also guard against diseases by opting for clean, inoculated corn seed from trusted distributors or nurseries.

Disease and crop infection is a sure-fire way of damaging your corn harvest. So picking resilient corn seeds can help steer you away from disappointment even before you’ve started planting.

Quick corn growing tips

  • Corn grows best in warm weather with temperatures around 68-86 °F (20-30 °C). If you are growing corn outside of this ideal temperature range then your corn may be small. Plan to provide corn with the correct growing climate to minimize the risk of your corn being small and not developing properly.
  • Provide corn plants with full sun to help them thrive. This means at least 6-8 hours of sunlight a day.
  • Keep in mind corn takes 60-100 days to mature, with an average being 90 days. So make sure you allow corn to reach maturity before harvesting them for deliciously sweet ears of corn.

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