How to Grow Sweet Corn in Greenhouse | Greenhouse Corn Guide

Make the most of your time and keep abreast of greenhouse tasks, from planting to harvesting Corn, with the help of advice you can trust.

Each one of us loves to munch golden yellow kernels, aka corn on the cob, summer corn salads, and the creamed corns. Yum!

Corns are a rich source of fiber, vitamins (Vitamin B12), minerals, and antioxidants.

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Most of us wonder whether it is possible to grow sweet corn inside a greenhouse! well, mark my words.


You can easily grow your greenhouse corn. Today we will guide you, on how to grow sweetcorn in the greenhouse. Are you ready?

Before getting into the details on how to grow sweet corn in your greenhouse, We assume that you already own a greenhouse. Most of the corn varieties grow up to 4-9 feet tall, therefore, the roof above the space in your greenhouse where you are planning to grow corn should be at least 9 feet tall. In case, if you don’t own a greenhouse, we have a detailed and easy to follow article on “How to build a greenhouse” which will help you build your own greenhouse (make sure that when you are building your greenhouse, the poles should be long enough so that the greenhouse is 9 feet tall).

Greenhouse Corn Requirements

To have the best results while growing sweet corns in your greenhouse one need to provide it with the ideal soil, sunlight and of course pollination.

Sweet corn is wind-pollinated in the fields. I will guide you in detail on how to provide this crop with pollination requirements inside your greenhouse.

Provide the crop with all these essentials and see how well they grow.

Let us start with the requirements.

1. Get to know your Greenhouse soil better

Do not let your grown veggies to struggle for ideal soil which suits them. It is a good idea to check soil pH whether it’s alkaline or acidic.

It is discouraging to see plants thrive for the best soil type. Checking the soil pH will help you decide which plants and seeds to choose.

The pH of the soil can be tested with kits Luster-Leaf-1601-Rapitest-Phosphorous. Sweet corn grows best at PH range from 6.0 to 6.6. It needs to have moderate to high levels of phosphorus and potassium.

To know the structure of the soil, feel the soil in your hand. It might contain a high proportion of clay, making it heavy and wet.

It might be having sand, making it light and dry – or something between the two, the perfect balance being known as loam.

The sandy loam soil is the soil that sweet corn and other vegetables thrive for.

It should be enriched with micro and macronutrients. For this, you need to regularly add bulk organic matter to your greenhouse soil.

Add bulk of compost or well-rotted manure, or mulching with leafmould. I recommend Charlie’s Compost

2. Watering

Sweet corn needs a sufficient amount of water during their growth cycle and after germination.

3. Light requirements for Sweet Corn

Sweet corns need adequate amount of sun exposure to make it available to the plant. You need to plant them in area in the greenhouse where maximum sunlight reaches the sweet corn.

Use grow lights in the greenhouse if you do not have the area with sunlight exposure or you are growing during winter. Checkout: “GREENHOUSE GROW LIGHTS” for more information on grow lights.

4. Pollination | How to provide Pollination in Greenhouse?

To provide the artificial means of pollination in the greenhouse for the sweet corns. You need to have a great ventilation system installed in the greenhouse. Like, use ventilators Amtrak-Galvanized-Upgraded14-Solar-Ventilates.

Another option is to use Riga Greenhouse Exaco-RIGA-XL-Square-Greenhouse it has installed ventilators and a lot more.

You can also use mechanical pollinators like the VegiBee-Garden-Pollinators. Or you can just hand pollinate them. Check out this video, where this dude is hand pollinating his greenhouse corns.

5. Area to plant Sweet Corns

These golden yellow kernel crop needs a huge area to grow. If you are planning to plant corn in the greenhouse so start to prepare enough space.

This needs careful planning because you are not only going to plant sweet corn there are other vegetables too.

So make sure you section and plan your greenhouse space accordingly.

If you do not have enough space then I would recommend Riga Greenhouse it will fit in your needs perfectly. Why? Because it provides the best ventilation with plenty of roof vents and the barn-style doors on both gables. Is not it amazing?

Here is the guide on how to plant, grow and harvest Sweet corn in the Greenhouse.

Planting | When to plant Greenhouse Corn

  1. Start sowing sweet corn seeds Gracefulvara-100PCS-Vegetables-Garden-Organic as the instructions given by the supplier.
  2. Plant seeds two weeks after the last spring frost date. Start planting earlier, sweet corn reasonably requires a long growth cycle.
  3. For successful germination, the soil temperature should be above 60°F (16°C) you can use Luster-Thermometer-Silver-Stainless-Steel to check soil temperature.

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Preparing Sweet corn bed

We already talk about the soil type and soil pH that sweet corn needs to grow in. Corn needs a lot of water so the soil should be well-drain. To hold moisture.

Plan your sweet corn plot rightly. By which I mean.

The planting pattern should be in blocks rather than following long rows pattern to plant corns. The blocks of corn should be at least 4 rows deeps.

This block pattern will make certain that the corn which is pollinated by VegiBee pollinators or ventilators in the greenhouse- has a greater chance of producing viable ears.

The pattern of planting corn is demonstrated in this video!

You should always cover your greenhouse corn bed with ground cover MAT because it will prevent weeds from growing in your greenhouse corn bed.

SO, You will not have to worry about weeds growing along with the corn. I would recommend you to use Dewitt Sunbelt Ground Cover.

This dude has covered his greenhouse cord bed with Ground Cover MAT and he is explaining, how greenhouse corn can be profitable.

How to Plant Greenhouse Corn

There is no need to sow the seeds on to modular trays or seeds tray. Plant them directly in the greenhouse. This will prevent sweet corn roots to get damaged due to transplanting. (However, the roots will recover fast, so if you want to use seedling trays you can just use them without worrying).

Plant sweet corn seeds 1.5 – 2″ deep and should be spaced 4-6″. Plot rows no closer than 30-36 inches.

Rows planted closer together may cause nutrient stress and cause shaded conditions.

Fertilize the plant with the following:

Provide the sweet corn with plenty of nitrogen, potassium and phosphorus supply. Nitrogen will not only boost sweet corn growth and is necessary for the production of amino acids. Nitrogen supply influences the flavor and nutritional content of sweet corn.

Apply 1 gram of nitrogen to your greenhouse corn per square feet, followed by side-dressing with 1-2 grams of nitrogen when the plants reach a height of 12-18 inches. This will provide an additional boost to your greenhouse corn. But if you want to grow organic then add bulk of decomposed compost (Charlie’s Compost).

You can also provide sweet corn with nitrogen sources by using forage legumes.

Sweet corns need moderate to high levels of phosphorus and potassium. Supply them with Rock phosphate Espoma-RP28-Rock-Phosphate-28-Pound and sulfate of potash-magnesia (K-Mag Sul-Po-Mag-0-0-21-5-Magnesia-Greenway-Biotech).

Apart from these fertilizers, you can incorporate bulk composts, manure, and rock mineral fertilizers.

After following all these steps, then it is time to water the plant. Done!

Care| How to Grow Sweet Corn in Greenhouse

In what ways we can take care of sweet corns. Let us see.

Keep sweet corn well watered as it has a shallow root system. Provide them with 5 gallons of water per sq. yard.

Reduce evaporation by using non-chemical weed suppression techniques like Flame weeding and living mulches.

When corn reaches a height of 3 to 4″, thin them so they are 8 to 12″ apart. Also, do not damage the roots while weeding.

Harvesting and Storing

How to harvest Sweet corn?

When to harvest sweet corns? The time to harvest sweet corn is when you see tassels begin to change their color to brown. The cobs start to swell. The kernels are full and milky.

This is the time when you should start harvesting.

How to remove the fruit from the rest of the body? Pull the ears downward and twist to take off the stalk.

Be mindful: if you miss the optimal harvest time, the corn’s flavor will drop fast, as sugars convert to starch.

Soon after harvesting sweet corn lose their sweetness. It is advisable to use them after harvest.

How to store Sweet corn

Freeze them in freezer bags (generally, 3 or 4 ears fills a quart), pat them flat (to remove air and so that they will stack easily) and seal the bag. 

Pest and diseases of Sweet Corns

The sweet corns are affected by a large number of insect pests, among the most widespread and damaging are corn earworm, European corn borer, corn rootworm, and cutworm.

Corn earworm

It is the most destructive pest of sweet corn.

It is also known as tomato fruitworm, cotton bollworm, and soybean pod worm.

Basically it is the larval stage of a moth. Which lays its eggs in the corn skill.

These worm pests cannot be controlled because they are protected by the husk while feeding.

There are biological control agents that prey on corn earworm eggs and larvae. These beneficial bugs are lady beetles, lacewings, syrphid fly larvae, and parasitic wasps.

We have detail article on beneficial insects here is a link: “ttps://

You can attract these beneficial bugs in your greenhouse by using a farmscaping strategy. In this strategy, we plant sweet alyssum, which is a short-lived flowering plant.

The flowers of sweet alyssum are attractive to parasitic wasps that prey on corn earworms.

Grow them in strips and sweet corn borders in the greenhouse to persuade the beneficial insects to stay in the greenhouse and control the pests that are affecting the sweet corns.

Finally, I want to mention one more thing. If you are growing corn for commercial purposes, then growing corn inside a greenhouse is not profitable. I would highly recommend that you grow corn outside in grow beds. However, you can grow corn seedlings inside your greenhouse and then transplant them outside, this will also increase your growing season. Check out this video.

But! Growing corn inside Greenhouse is Amazing and More fun,

If you want to have some fresh corn for your family, I would definitely recommend you grow corn inside the greenhouse.

I hope that you got a ton of information from this article. If you want to return the favor, share this article with your friends, It will help us a lot.

How to grow corn in greenhouse, Green house corn guide (2)