4 Best Fertilizer for Corn | How & When to Use

There’s little more satisfying than picking an ear of sweetcorn that you have watched grow and nurtured throughout the summer months. The ceremonious unwrapping of the husk is akin to a highly anticipated present at Christmas time. Once disrobed, those vibrantly yellow, plump kernels lay in perfectly regimented lines ready to be devoured.

Whether you’re a dab hand at growing corn or fancy growing your own this year, one thing is for sure. Sweetcorn plants are heavy feeders and benefit both from a health and also growing perspective if they are fertilized regularly. So, if you want to be set up for sweet growing success here are my top tips for buying and using the best fertilizer for corn.

Choosing the Best Fertilizer for Corn

There are a few things that you need to get right if you want a successful sweetcorn harvest. Having enough sunshine and water are high up on the list of priorities, as is nutrient-rich soil and plenty of well-rotted compost. In addition, corn plants are heavy feeders and need regular applications of fertilizer to ensure a healthy and plentiful crop of corn.

The roots of sweet corn plants will quickly absorb any nutrients in the soil and so fertilizing at particular times during the growing season, is needed to boost the various stages of the sweetcorn plants’ growth pattern.

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N-P-K Corn Fertilizer Ratio

The fertilizer market is flooded with products that offer a whole plethora of benefits when it comes to the successful growing of corn plants.

The majority of these fertilizers will state the N-P-K ratio content of the product. N-P-K stands for (N) nitrogen, (P) phosphorus, and (K) potassium and these letters will be represented by a number.

For sweetcorn plants look for a fertilizer that contains an N-P-K ratio with a higher proportion of nitrogen this is because sweetcorn plants will quickly deplete the soil of this important macronutrient. In addition, your growing sweetcorn plant will also need phosphorus as well as potassium until it reaches maturity. For example, a sweetcorn fertilizer with the numbers 20-15-15 on the label means that this product contains 20% nitrogen, 15% phosphorous, and 15% potassium.

Granules Vs Liquid Fertilizer

Both granules and liquid fertilizers are popular choices when it comes to feeding sweetcorn and both are available to buy with varying amounts of N-P-K depending on your plant’s feeding requirements. The main difference between these two types of fertilizer other than whether they are solid or liquid is how they are administered. Let’s look at this in a little more detail now.

Liquid Fertilizer

Liquid fertilizers can be bought either as a concentrated formula that will need to be diluted with water or in a ready-to-use format.

The former will need to be measured out into a handheld pr backpack sprayer and mixed with water before applying. Ready-to-use liquid fertilizers require no messy mixing and can often be used straight from the container in which they are supplied. Some containers even come with a spray nozzle attachment that you simply screw on.

The downside of liquid fertilizers is spillages and drift either when the product is being mixed or if it is administered on a windy day. If drift occurs, fertilizer may land on leaves or stalks that can sometimes cause fertilizer burn.

Granular Fertilizer

When using granules to fertilize sweetcorn, the best method to use is a technique known as a side dressing. This is when a shallow trough is made approximately 6 inches away from the stalk of the plant and granules are then sprinkled into the trough before being watered in. This method ensures that the granular fertilizer can quickly be absorbed by the roots.

Organic Corn Fertilizer

When it comes to growing edible plants, organic fertilizers are always best because they don’t contain chemicals that could be harmful to our health if ingested.

If you have used a corn fertilizer and are unsure of the ingredient list, then make sure that you wash ready-to-eat vegetables well in plenty of water to remove any traces of fertilizer. 

Ideal pH for Corn to Grow

The ideal pH level for corn plants is 5.8 to 7. Planting in organic-rich compost, mulching, and providing additional nitrogen will all contribute to maintaining the required pH level throughout the year. It’s a good idea to test the soil pH levels regularly using a soil test kit since corn plants can quickly deplete nutrients from the soil.

If you need to lower the soil pH – and by this, I mean making the soil more acidic – I recommend that you mulch regularly and make sure your soil is rich in organic matter (compost) even before planting.

Soil that is naturally acidic tends can be problematic for corn plants and may lead to magnesium deficiencies. In turn, this reduces the corn plant’s ability to absorb nitrogen.

Use lime or wood ash to increase alkaline levels (raise the soil pH).

4 Best Corn Fertilizer Reviews

It’s a well-known fact that cooking sweetcorn as soon as possible after they have been picked ensures maximum sweetness and flavor as well as that deliciously creamy texture. But you’ve got to grow it first and to really hit the sweet spot of perfection your corn plants are going to need feeding.

Here is my pick of the 4 best corn fertilizers. All of them selected having first tried, tested, consulted with experts and received feedback and reviews from corn growers.

1. Down to Earth Vegetable Garden Fertilizer 4-4-4

Down to Earth Organic Vegetable Garden Fertilizer

My first choice is from Down-to-Earth. It’s their Organic granular feed specifically designed for all types of vegetable gardening. It has an N-P-K ratio of 4-4-4 which means it is suitable for use right from the start of the growing season.

These guys know a thing or two when it comes to organic gardening and their recommendation for using this fertilizer perfectly complements corn plant growing.

They recommend applying it to vegetables that have been planted in nutrient-rich organic compost. Doing so helps to create the right environment for not only corn growing but for all of your vegetable growing needs.

I’ve found this to be the perfect fertilizer for newly planted corn seedlings. It is balanced and gentle enough to be used regularly without ever worrying about fertilizer burn, even to the most tender of plants. Click here for Down To Earth Organic Veg Fertilizer.

How To Use: Dig a 3-inch trough 6 inches from the base of your row of corn. Apply ½ cup for each foot of cornrow and work into the soil. Water in thoroughly. Repeat twice per month throughout the growing season.

Customer Reviews: This is reasonably priced and provides wonderfully organic results. Plus it doesn’t have the typical odor associated with organic products. This is the best fertilizer for corn for sure.


  • Equal-ratio NPK means it is gentle enough for heavily amended soil and new seedlings
  • No harsh, organic odor


  • May need to switch to a high nitrogen fertilizer as the season progresses

2. Espoma Garden-Tone Plant Food Fertilizer 3-4-4

Espoma Garden-Tone Plant Food, Natural & Organic Fertilizer

Next up is an organic granular formula from Espoma and it is the choice to opt for when soil is already nitrogen-rich from using compost and regularly mulching.

This one contains Espoma’s trademark Bio-tone microbes. These are known to provide a consistent and steady flow of nutrients into the soil. In turn, your corn plants will grow strong and robust roots, stalks, and also leaves.

This is a slow-release formula that allows you to apply the first application in spring to new corn plant seedlings and then repeat monthly thereafter throughout the growing season. Check the latest price of Espoma Garden-Tone Plant Food online here.

How To Use: Side dress approximately 10 days after planting out new seedlings by digging a 3-inch trough approximately 6 inches away from corn stalks. Work the recommended amount into the trough, dig in lightly, and then water. Repeat monthly throughout the growing season until harvest.

Customer Reviews: Corn growers report increased-size crops but say this is best used in soils that are already nitrogen-rich.


  • High yields from an organic product
  • Trademark Bio-tone formula adds additional nutrients to help condition soil


  • Organic odor may be attractive to pets

3. Dr. Earth Organic Tomato, Vegetable & Herb Fertilizer 4-6-3

Dr. Earth Organic Tomato, Vegetable & Herb Fertilizer

Dr. Earth’s Organic fertilizer is a versatile product that can be used either as a side dressing in granular form or as a water-soluble tea.

This one contains no less than seven different types of beneficial macrobiotics, plus probiotics that will help your corn plants to absorb nutrients more efficiently. This means bigger crops and sweet, tender ears of corn. Click here for Dr. Earth Home Grown Vegetable Fertilizer from Amazon.com.

I found this most beneficial for corn plants that were already benefitting from nutrient-rich organic soil that had been composted and mulched prior to planting. I used this once my plants were established and I knew they would benefit from some additional phosphorous to further enhance growth and encourage healthy growth and the development of those all-important husks.

How To Use: For new plantings: add 1 ½ cups for every 10 feet of cornrows. For established plants, apply ¾ cup for every 10 feet of growing area. Repeat every 2 months.

Customer Reviews:  This is a great value-for-money product that has a long shelf life for season-long usage.


  • Contains probiotics and seven beneficial microbiotics to nourish soil
  • Great value for money


  • Pets and wildlife may be attracted to the organic smell

4. The Old Farmer’s Almanac Organic Tomato & Vegetable Plant Food 8-4-8

The Old Farmer's Almanac Organic Tomato & Vegetable Plant Food

My final pick from Farmer’s Almanac is an organic plant food that boasts a prestigious OMRI listing.

Whilst not specifically for corn plants and used more widely as a general-purpose vegetable fertilizer, this feed provides both quick and slow-release nutrients in all stages of growth. I opt for this if my corn plants look a little stressed and need a boost before the husks begin to fully develop.

Use this granular fertilizer if you are a little averse to the harsh odor that some other organic feeds can often omit. Prices for Old Farmer’s Almanac Organic Plant Food can be found here.

How To Use: Following the recommended doses per foot of cornrow, sprinkle granules evenly in a 3” trough. Repeat every 6-8 weeks.

Customer Reviews: A great all-around vegetable fertilizer that provides results even in harsh climates and regions with short growing seasons.


  • No Harsh odors or manure
  • Immediate results for ailing corn plants


  • Over-watering organic feeds may result in fungus growth

How to Fertilize Corn

Provide young plants or corn seedlings with a head start by ensuring that the soil in which you plant them is packed with nutrient-rich organic matter. The best way to do this is by adding compost to the soil before planting.

You can continue this supplementary boost of organic nutrients, by regularly adding a layer of mulch over the soil.

Once planted young plants and seedlings need a light and balanced fertilizer. Corn plants need nutrients from the get-go to encourage roots, stalks, and leaves to grow steadily and healthily. Once these elements are established, the plant will be able to accommodate the next growth stage of the ears and husks.

Too strong or too much feed in the early growing stages can stunt growth or even kill-off young, immature plants.

Once established, corn plants need regular feeding with a high-dose nitrogen fertilizer. Nitrogen helps to further develop roots, and corn plants absorb it quickly and in abundance with soil rapidly becoming depleted of nitrogen as the growing season progresses.

In addition to nitrogen, phosphorus and potassium are also important as they help to strengthen roots and increase the stability of stalks. In addition, these vital macronutrients help to ward off any potential pests and diseases as well as increase crop yield.

Fertilizer can be applied either in liquid form or as a granular feed. The most commonly used technique is called side dressing. Where a shallow trough is dug approximately 6 inches away from the stalk of the corn plant. Granules are sprinkled into the trough and then watered in. This method ensures that nutrients are quickly transferred and absorbed by the roots which is exactly where the corn plant needs them.

How Often Feed Corn

Corn plants can handle being fertilized regularly throughout the growing season. Begin fertilizing seedlings and young plants with a gentle fertilizer as soon as they have been planted outdoors.

Continue to fertilize regularly as the season progresses with a high-dose nitrogen fertilizer. This can be continued right up until harvest time.

Over Fertilizing Corn

It’s difficult to over-fertilize corn plants since they are heavy feeders and need high doses of nitrogen and phosphorus in order to thrive.

To avoid subjecting your corn plants to potential fertilizer burn, avoid splashing liquid fertilizer or sprinkling granules too close to the stalk or leaves. If you do manage to get fertilizer products on these areas of your corn plant, rinse thoroughly with water to wash any excess fertilizer away.

You may also be interested in Why Has My Corn Plant Got Yellow Leaves

When to Fertilize Corn

Begin a regular feeding program for your corn as soon as you plant them outdoors. This will depend on your region but for most it will be early to mid-spring.

Fertilizing can continue regularly depending on the fertilizer product that you choose and the specific manufacturer’s instructions.

Feeding can continue throughout the growing season right up until harvest time.

Verdict: Best Fertilizer for Corn

So, there we have it. Not only does corn need regular and consistent watering and soil that is rich in nutrients, but they also need feeding regularly throughout the growing season. Not only that, they prefer different amounts of macronutrients depending on where they are in the growing cycle. So what is going to benefit your corn right now? Is it Down to Earth Organic Vegetable Garden Fertilizer? An N-P-K balanced organic fertilizer perfectly complements already nutrient-rich soil.

Or do your corn plants need Espoma Garden-Tone Plant Food? An organic, granular fertilizer that contains their trademark Bio-tone microbes that will provide a consistent and steady flow of nutrients into the soil to ensure your corn plants grow strong with robust roots, stalks, and also leaves.

Alternatively, will your corn plants benefit from Dr. Earth Organic Tomato, Vegetable & Herb Fertilizer? This feed gives you the option of either conventional side dressing or using it as an organic fertilizer tea. Perfect for boosting phosphorus once corn plants are established.

FAQ’s Fertilizing Sweet Corn

If you still have questions about growing corn, take a look at some of the regularly asked questions that I get asked here at The Yard & Garden.