How to Grow Kale in a Greenhouse

Attention: Are you interested in growing your own nutritious and versatile vegetables? Look no further than kale! With its numerous health benefits and ease of cultivation in a greenhouse, kale is the perfect crop for you.

In this article, I will reveal the secrets to successfully growing kale in a greenhouse. From selecting the ideal variety to effectively managing pests and diseases, I will guide you through every essential step towards a bountiful harvest.

Get ready to embark on this exciting journey!


Key Takeaways

  • Choose a kale variety that can tolerate the specific conditions in your greenhouse.
  • Maintain the right temperature range and humidity level for healthy growth.
  • Provide adequate sunlight or use grow lights for photosynthesis.
  • Ensure proper ventilation to prevent heat buildup and disease.


Choosing the Right Variety of Kale

When choosing the right variety of kale, it’s important to consider the climate of your greenhouse. The first step is to assess the temperature and humidity levels inside your greenhouse.

Kale thrives in cool weather, so if your greenhouse tends to get too hot, you’ll need to choose a variety that can tolerate higher temperatures. On the other hand, if your greenhouse is on the cooler side, you can select a variety that is more cold-tolerant.

Additionally, consider the amount of sunlight your greenhouse receives. Some kale varieties require more sunlight, while others can handle partial shade.


Preparing the Greenhouse Environment

To ensure optimal growth, it’s important to create the right environment inside the greenhouse for growing kale. I’ve found that by paying attention to the following factors, I can create the ideal conditions for my kale plants:

– Temperature and Humidity:

Maintaining a temperature range of 60-70 degrees Fahrenheit during the day and around 50 degrees Fahrenheit at night is crucial for kale’s growth. Keeping the humidity level around 40-50% helps prevent diseases and promote healthy growth.

– Light and Ventilation:

Providing 10-12 hours of direct sunlight or using grow lights is essential for kale’s photosynthesis. Ensuring proper ventilation by using fans or vents helps prevent heat buildup and disease.


Planting Kale Seeds or Seedlings

When it comes to planting kale, there are a few key points to consider: seed vs seedlings, planting techniques, and germination time frames.

Personally, I prefer starting with seeds as it allows me to have more control over the entire growing process.

Additionally, when planting, I find it crucial to ensure proper spacing to allow the kale plants to thrive and receive adequate sunlight.

Lastly, it’s important to note that germination time frames can vary depending on factors like temperature and soil moisture, so it’s essential to keep an eye on the plants and provide the necessary care during this crucial stage.


Seed Vs Seedlings

The decision to use seedlings or seeds depends on your specific greenhouse setup and desired time frame. When it comes to growing kale, there are pros and cons to both options. Here are a few things to consider:



  • Ready to transplant: Seedlings are already established and can be transplanted directly into your greenhouse, saving you time and effort.
  • Reduced risk: Since seedlings have already sprouted, you have a higher chance of success compared to starting from seeds.


  • Limited variety: Seedlings may have limited variety options compared to seeds, as not all kale varieties are readily available as seedlings.
  • Cost: Buying seedlings can be more expensive than purchasing seeds.



  • More variety: Seeds offer a wider range of kale varieties to choose from, allowing you to experiment and find the perfect one for your taste and preferences.
  • Cost-effective: Seeds are generally cheaper than seedlings, making them a more budget-friendly option.


  • Longer time frame: Starting from seeds requires more time and patience, as you’ll need to wait for them to germinate and grow into seedlings before transplanting them into your greenhouse.
  • Higher risk: There is a higher risk of failure when starting from seeds, as not all seeds may germinate successfully.

Ultimately, the decision between using seedlings or seeds depends on your specific needs, preferences, and resources. Consider your greenhouse setup, desired time frame, and the level of risk you’re willing to take, and choose the option that aligns best with your goals.


Planting Techniques

Planting techniques can vary depending on your specific preferences and the resources available to you. When it comes to growing kale in a greenhouse, I have found a few techniques that work well for me.

First, I like to prepare the soil by adding compost and ensuring it is well-drained. Then, I start by planting kale seeds directly into the soil, spacing them about 6 inches apart. I gently cover the seeds with a thin layer of soil and water them lightly.

Alternatively, you can also start with kale seedlings, which can be transplanted into the greenhouse soil. Regardless of the method you choose, it’s important to keep the soil consistently moist and provide adequate sunlight.

With proper care and attention, your kale plants will thrive in the greenhouse environment.


Germination Time Frames

To ensure successful germination, I keep the soil consistently moist and provide adequate sunlight for my kale seeds or seedlings. It’s important to monitor the moisture levels in the soil regularly, as kale seeds need moist conditions to sprout.

I make sure to water the soil evenly and avoid over-watering, as this can lead to rotting or fungal diseases.

In terms of sunlight, I place my kale seeds or seedlings in a location that receives at least 6 hours of direct sunlight each day. This helps the seeds to germinate faster and promotes healthy growth.

Additionally, I use a seedling heat mat to maintain the ideal temperature for germination, which is around 70-75°F (21-24°C).

Following these steps has resulted in successful germination for my kale plants.


Providing Proper Watering and Fertilization

When it comes to growing healthy plants, two crucial factors to consider are watering frequency and amount, as well as choosing the right fertilizer.

As a gardener, I’ve learned that finding the balance between under-watering and over-watering is essential for plant growth.

Additionally, selecting the appropriate fertilizer not only provides essential nutrients but also ensures that plants thrive.


Watering Frequency and Amount

Make sure you’re not overwatering the kale in the greenhouse. It’s important to find the right balance when it comes to watering frequency and amount. Overwatering can lead to root rot and other issues that can harm the kale plants.

Here are some tips to help you water your kale properly:

Watering frequency:

  • Check the soil moisture regularly by sticking your finger about an inch deep into the soil. If it feels dry, it’s time to water.
  • Water the kale plants deeply but less often. Aim to water them once or twice a week, depending on the weather conditions.

Watering amount:

  • Provide enough water to thoroughly moisten the root zone.
  • Avoid excessive watering that leads to waterlogged soil.


Choosing the Right Fertilizer

You’ll want to choose the right fertilizer for your kale plants in order to provide them with the necessary nutrients for healthy growth. When it comes to fertilizers, there are a few options to consider.

Personally, I prefer using an organic fertilizer for my kale plants. It’s important to look for a fertilizer that is specifically formulated for vegetables or leafy greens. These fertilizers typically contain a balanced mix of nitrogen, phosphorus, and potassium, which are essential for plant growth.

Additionally, organic fertilizers are gentle on the soil and promote long-term soil health. I find that using organic fertilizers not only helps my kale plants grow better, but it also ensures that my harvest is free from harmful chemicals.


Managing Pests and Diseases

To keep pests and diseases at bay, it’s important to regularly inspect your kale plants in the greenhouse. I make it a habit to check my plants every few days to catch any signs of trouble early on.

Here are a few things I keep an eye out for:


  • Aphids: These tiny insects can quickly multiply and damage your kale plants. Look for clusters of small, green bugs on the leaves.
  • Caterpillars: These voracious eaters can munch through your kale in no time. Keep an eye out for chewed leaves and frass, which looks like small black droppings.


  • Downy Mildew: This fungus thrives in cool, humid conditions. Look for yellow or brown spots on the leaves, along with a fuzzy white or gray growth on the undersides.
  • Powdery Mildew: This fungus appears as a powdery white coating on the leaves. It can spread rapidly in warm, dry conditions.


Harvesting and Storing Kale

After successfully managing pests and diseases in my greenhouse-grown kale, it’s time to reap the rewards of my hard work.

Harvesting and storing kale is a straightforward process that ensures I have a fresh supply of this nutritious vegetable throughout the year. When the leaves are large and vibrant, I simply snip them off the plant, leaving a few inches of stem to encourage regrowth. It’s important to harvest regularly to prevent the leaves from becoming tough and bitter.

Once harvested, I wash the kale thoroughly and dry it before storing it in airtight containers or freezer bags. I can store kale in the refrigerator for up to a week or freeze it for longer-term storage.

Having a bountiful supply of homegrown kale is incredibly satisfying and encourages me to continue nurturing my greenhouse garden.


Frequently Asked Questions


Can Kale Be Grown in a Greenhouse During All Seasons?

Yes, kale can be grown in a greenhouse during all seasons. It thrives in the controlled environment, allowing for consistent temperature and protection from harsh weather conditions.


What Is the Ideal Temperature Range for Growing Kale in a Greenhouse?

The ideal temperature range for growing kale in a greenhouse is between 60 and 70 degrees Fahrenheit. This allows for optimal growth and ensures that the kale plants receive the right amount of warmth and sunlight.


How Long Does It Take for Kale Seeds to Germinate in a Greenhouse?

It usually takes around 5-7 days for kale seeds to germinate in a greenhouse. I find that maintaining a consistent temperature and providing adequate moisture helps speed up the germination process.


Can Kale Be Grown Hydroponically in a Greenhouse?

Yes, kale can definitely be grown hydroponically in a greenhouse. It’s a great way to maximize space and control nutrient levels. Plus, it allows for year-round growth and eliminates the need for soil.


Is It Necessary to Use Artificial Lighting in a Greenhouse to Grow Kale?

No, it’s not necessary to use artificial lighting in a greenhouse to grow kale. Natural sunlight can provide the necessary light for kale to grow properly.

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