The Complete Guide To Growing Hydroponic Broccoli

The Complete Guide To Growing Hydroponic Broccoli

It is currently September here in Michigan, which means the colder months are upon us. While many are doing fall cleanup in their gardens outside, I am planning my winter garden inside – with my hydroponic garden setup! One of my favorite hydroponic crops to grow is broccoli. In this article, we’ll walk you through the best equipment to use, what varieties fare best with hydroponic systems, and a step-by-step guide on how to grow hydroponic broccoli.

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What Varieties Of Broccoli Are Best For Hydroponics

When choosing a variety of broccoli for hydroponic cultivation, it’s best to select those that are well-suited to compact growth, have a shorter maturity period, and produce smaller, tight heads. Here are some broccoli varieties that are commonly recommended for hydroponic growing:

  1. Green Magic: Green Magic broccoli is a popular choice for hydroponics due to its compact growth habit and short maturity period. It produces small to medium-sized, dark green heads with excellent flavor.
  2. Di Cicco: Di Cicco is an heirloom broccoli variety known for its side-shoot production. This means it continues to produce smaller florets even after the main head is harvested, providing an extended harvest period. It’s ideal for continuous cropping in hydroponics.
  3. Calabrese: Calabrese broccoli is a traditional variety that produces well in hydroponic systems. It forms tight, compact heads and has a relatively short maturity period.
  4. Belstar: Belstar broccoli is a hybrid variety specifically bred for controlled environment and hydroponic cultivation. It has a uniform, dome-shaped broccoli head and is resistant to bolting.
  5. Pacman: Pacman broccoli is known for its unique appearance, with a central head surrounded by numerous small side shoots. This variety is well-suited for hydroponic systems, as it continues to produce side shoots after the main head is harvested.
  6. Apollo: Apollo broccoli is a compact, early-maturing variety that is suitable for hydroponic cultivation. It produces small to medium-sized heads and has good disease resistance.
  7. Marathon: Marathon broccoli is another hybrid variety designed for controlled environment and hydroponic production. It has a relatively short growth cycle and produces uniform, dense heads.
  8. Gypsy: Gypsy broccoli is a compact variety that matures quickly. It’s well-suited for hydroponics and produces smaller heads with a mild flavor.

How To Germinate Broccoli Seeds

Broccoli seeds will take up to 14 days to germinate. There are a few methods you can use to germinate seeds for hydroponic gardening, but I always start my seeds in rockwool plugs like these. Soak rockwool plugs for a full day, then sow your seeds directly into the top of the soaked cube. Gently press the seed down to ensure good contact.

Using a tray with a lid (like this) you can easily maintain humidity while the seeds germinate. Keep seeds consistently moist with a spray bottle and lift the lid a few times a day to prevent mold from growing. Broccoli seeds typically germinate best at a temperature range of 70°F to 85°F.

​Transplanting Broccoli Seedlings Into Your Hydroponic System

Once your broccoli seedlings have 2-3 true leaves, they are ready to transplant into your hydroponic system. For a standard bucket hydroponic setup, I recommend using a material like clay pebbles as the growing medium. Fill your bucket lid most of the way up with clay pebbles, leaving a small hole in the middle for your seedling.

Place your seedling in the small hole and fill in the space around it with additional pebbles. The top of the rockwool plug should be level with the top of your pebbles. Make sure the root system of your seedlings can easily reach the waters.

Harvested heads of broccoli grown in an indoor hydroponic setup.

Hydroponic Broccoli Heads

What Type Of Hydroponic System Works Best For Broccoli?

​DWC Hydroponic Bucket System

If you are new to hydroponic gardening, you will want to invest in the type of hydroponics systems that are easy to assemble and maintain. I recommend starting with a deep water culture system like a bucket hydroponic setup. This type of system involves just a handful of components and is relatively easy to set up and maintain. There are many tutorials on how to do DIY bucket hydroponic systems available online, but you can also buy a complete bucket kit for relatively low cost overall.

My first hydroponic system was the VIVOSUN Hydroponics Grow System Kit and it is still one of my favorites 3 years later. This kit contains everything you need (except lights) and is very easy to assemble. As broccoli is a medium-sized plant, you can fit up to 4 broccoli plants in one 5-gallon bucket by purchasing an adapter lid with more plant plugs.

Hydroponic Tower System

Broccoli can also be grown in some of the larger hydroponic towers as well. Hydroponic towers are great for small spaces because their footprint is small relative to how many plants most towers can accommodate. Not all hydroponic towers are great options, you will want to be sure the holes in your tower are spaced far enough apart to accommodate a mature broccoli plant. Additionally, you will need extra lighting to ensure each side of the tower receives appropriate light for growing broccoli.

The Gardyn Home Kit 3.0 is our top choice for vertical growing systems among indoor growers. For starters, this systems is absolutely stunning! It has a sleek, modern design with a small footprint that looks beautiful in any room of your home. The Gardyn tower system includes everything you need to start your hydroponic setup, from nutrients and seeds to grow lights and cubes. The system is overall easy to use and maintain, uses less water than other hydroponic setups, and is a great way for home gardeners to start hydroponic gardening.

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Best Nutrients For Hydroponic Broccoli

Set up your hydroponic system according to the factory instructions. Add your chosen nutrients. I use the Fox Farm Hydro Liquid Nutrients for any of my hydroponic crops. This is an organic fertilizer that I have had a lot of success with overall, especially rapid growth for mature plants. There are a lot of nutritional solutions on the market overall, but I have found that once you find a good brand you can typically use that on the majority of plants you grow.

Optimal Light Conditions For Hydroponic Broccoli

  • Broccoli plants require moderate to high light intensity for optimal growth. Providing them with an average of 12 to 16 hours of light per day is recommended during the vegetative growth stage.
  • Broccoli plants benefit from a full spectrum of light, but they have specific preferences for certain wavelengths. Blue light (400-500 nanometers) is crucial for vegetative growth and leaf development, while red light (600-700 nanometers) promotes flowering and head formation.
  • High-quality LED grow lights designed for plant growth often provide a balanced spectrum that includes blue and red light, making them suitable for hydroponic broccoli.
  • Once the broccoli plants begin to form heads (the flowering stage), reduce the light duration to 8 to 10 hours per day. This reduction in light duration helps trigger head formation.
An indoor grow light illuminates a single vegetable plant for an indoor garden.

Pest And Disease Management

While hydroponic cultivation can help reduce the risk of some pests and diseases that affect soil-grown crops, hydroponic gardeners can still run into issues. Here are some common pests and diseases to watch out for when growing hydroponic broccoli, along with tips on how to prevent or manage them:

Common Pests:

  1. Aphids: These small, soft-bodied insects can cluster on the undersides of leaves and feed on plant sap. They can be controlled through the use of insecticidal soap or neem oil.
  2. Whiteflies: Whiteflies are tiny, winged insects that can quickly infest broccoli plants. They feed on plant juices and can spread diseases. Use yellow sticky traps or neem oil to control them.
  3. Cabbage Loopers: The cabbage looper is a green caterpillar that can chew on broccoli leaves. Hand-picking or using biological controls like beneficial nematodes can help manage them.
  4. Spider Mites: Spider mites are tiny arachnids that can damage plant leaves by feeding on them. Use a strong spray of water to dislodge them or apply neem oil.

Common Diseases:

  1. Powdery Mildew: Powdery mildew appears as a white, powdery substance on plant leaves. Maintain good air circulation, keep humidity levels in check, and apply fungicides if necessary.
  2. Downy Mildew: Downy mildew causes yellow spots on leaves with downy growth on the undersides. Ensure proper ventilation, manage humidity, and apply copper-based fungicides as a preventive measure.
  3. Root Rot: Root rot is a fungal disease that affects the roots, leading to wilting and plant decline. Maintain a well-aerated root zone and avoid overwatering to prevent root rot.
  4. Pythium: Pythium is another fungal pathogen that can cause damping-off of seedlings and root issues. Preventative measures include using clean growing media and maintaining proper sanitation.

Prevention and Management Tips:

  1. Quarantine: Inspect new plants or growing media before introducing them to your hydroponic system to avoid introducing pests and diseases.
  2. Good Hygiene: Practice good hygiene by sanitizing equipment and tools, and regularly cleaning the hydroponic system to prevent the buildup of algae and pathogens.
  3. Monitor Regularly: Regularly inspect your broccoli plants for any signs of pests or diseases. Early detection allows for prompt intervention.
  4. Biological Controls: Consider using beneficial insects like ladybugs or parasitic wasps as a natural way to control pests in your hydroponic system.
  5. Proper Ventilation: Ensure proper ventilation and air circulation in your hydroponic grow area to reduce humidity levels and prevent the buildup of moisture, which can promote fungal diseases.
  6. Clean Water: Use clean, filtered water in your hydroponic system to avoid introducing contaminants or pathogens.
  7. Organic Controls: If you prefer organic methods, explore options like neem oil, diatomaceous earth, or beneficial microorganisms for pest and disease control.

By following these preventive measures and monitoring your hydroponic broccoli plants regularly, you can minimize the risk of pests and diseases and ensure a healthier and more productive crop.

How To Harvest Hydroponic Broccoli

Harvesting hydroponic broccoli requires careful timing to ensure you pick the heads at their peak flavor and quality. Here are the steps to harvest hydroponic broccoli:

  1. Monitor Growth: Keep a close eye on your broccoli plants as they grow. Keep in mind that broccoli is a cool-weather crop and will not want a very warm growing space. The heads should be firm and tight, with compact florets. When they reach the desired size, it’s time to harvest.
  2. Determine Readiness: Broccoli heads are ready to harvest when they are 4 to 8 inches (10 to 20 centimeters) in diameter, depending on the variety. The ideal size may vary, so refer to the specific recommendations for the broccoli variety you are growing.
  3. Use Sharp Pruning Shears or Knife: To harvest broccoli, use clean, sharp pruning shears or a knife. It’s essential to make a clean cut to avoid damaging the plant.
  4. Positioning the Cut: Locate the main stem just below the head of broccoli. Position your shears or knife at a slight angle, about 5-6 inches (13-15 centimeters) below the head, and make a clean, swift cut.
  5. Harvest in the Morning: For the best flavor and nutrient retention, harvest broccoli heads in the morning when they are at their freshest.
  6. Leave Some Stalk: After harvesting the main head, don’t remove the entire plant. Leave the plant in place, and it may continue to produce smaller side shoots or florets. These side shoots are edible and can be harvested as they reach an appropriate size.
  7. Check for Pests: While harvesting, inspect the plants for any signs of pests or disease. Remove any affected leaves or plant parts to prevent further infestation.
  8. Handle with Care: Handle the harvested broccoli heads carefully to avoid bruising or damaging them. Place them gently in a container or basket.
  9. Storage: Hydroponically grown broccoli is best when consumed shortly after harvest. However, if you need to store it, place the harvested heads in a plastic bag or airtight container in the refrigerator. Use them within a few days for the best quality.
  10. Continuous Harvest: As mentioned earlier, hydroponically grown broccoli plants can continue to produce side shoots after the main head is harvested. Keep monitoring your plants, and when the side shoots reach a suitable size (3-4 inches or 7-10 centimeters), repeat the harvesting process.

Harvesting hydroponic broccoli at the right time ensures that you enjoy the freshest and most flavorful heads. Regular harvesting can also encourage the plant to produce additional side shoots, extending your harvest period.

Why Broccoli Is A Great Crop For Hydroponic Gardens

  1. Short Growing Season: Broccoli is a cool-season vegetable that typically requires a longer growing season in traditional soil-based gardens. In hydroponics, you can control the environmental conditions, including temperature and light, allowing you to grow broccoli year-round regardless of the outdoor climate.
  2. Space Efficiency: Broccoli plants can be grown closely together in a hydroponic system, making efficient use of space. This is particularly advantageous for growers with limited space.
  3. Higher Yields: Hydroponic systems provide a consistent supply of nutrients and water directly to the plant roots, resulting in faster growth and potentially higher yields compared to soil-based cultivation.
  4. Nutrient Control: Hydroponic systems allow precise control over nutrient levels and pH, ensuring that broccoli plants receive the ideal balance of nutrients for optimal growth. This can lead to healthier and more productive plants.
  5. Reduced Pest and Disease Pressure: Hydroponic systems can be set up in a controlled indoor environment, which reduces the risk of pests and diseases that can affect broccoli in traditional gardens. This can lead to a decreased need for pesticides and fungicides.
  6. Water Efficiency: Hydroponics is generally more water-efficient than soil-based gardening since water is recirculated in the system. Broccoli plants receive water directly at their roots, reducing water wastage.
  7. Consistent Quality: Hydroponically grown broccoli tends to have consistent size, shape, and quality. This can be particularly appealing to commercial growers and consumers who value uniformity.
  8. Faster Growth: Hydroponic systems often promote faster growth due to the ideal growing conditions provided. This can result in quicker harvests and more frequent crop cycles.
  9. Year-Round Production: With hydroponics, you can control the environment to provide the required conditions for broccoli growth regardless of the season. This allows for continuous, year-round production.
  10. Cleaner and Controlled Environment: Hydroponic systems are typically grown indoors or in protected environments, which means less exposure to external contaminants and pollutants, leading to cleaner and potentially healthier crops.

While broccoli can thrive in hydroponic systems, successful cultivation requires attention to factors such as nutrient balance, lighting, temperature, and humidity. However, when properly managed, hydroponic broccoli can offer numerous advantages for growers seeking efficient, high-quality, and year-round crop production.

Learn More About Hydroponic Gardening

Hydroponic gardening is a great way to extend your garden through the winter months. This type of gardening can be highly rewarding as it results in fast growth and high crop-yield. To learn more about hydroponic gardening, check out these guides!

An indoor hydroponic garden with LED lights and the best air pumps for healthy crop production.

Indoor Hydroponic Garden with LED Lights