1. Introduction

At Grow Sow Greener UK, we believe that growing your own food isn’t just a hobby—it’s a step toward a healthier, more sustainable world. Our mission is simple: to empower as many people as possible to cultivate their own fresh, nutritious produce, no matter their space, experience, or resources.

Microgreens, especially Broccoli Calabrese, are an excellent way to start. These tiny greens pack a powerful punch—bursting with flavor, loaded with essential nutrients, and incredibly easy to grow in just a matter of days. Whether you have a spacious garden or just a sunny windowsill, you can grow your own superfood with minimal effort.

But why should you bother growing your own microgreens instead of buying them? Food security, health, and sustainability are just a few of the compelling reasons. Store-bought greens travel miles before reaching your plate, losing nutrients and increasing your carbon footprint. Growing your own means fresher food, reduced waste, and the satisfaction of knowing exactly where your greens come from.

In this guide, we’ll take you through everything you need to know to successfully grow Broccoli Calabrese microgreens at home—from seed selection to harvest. Along the way, we’ll highlight the environmental, health, and cost-saving benefits of growing your own.

This guide is crafted for both professional and home growers and details every step of the process using our specialized tray systems.

2. Organic Broccoli Calabrese Microgreens: Variety Overview & Health Benefits

Key Features:

• Latin Name: Brassica Oleracea Botrytis Cymosa
• Certified Organic: Yes
• Seed Treatment: Untreated and lab‐tested for pathogens
• Flavor & Texture: A mild, fresh, slightly peppery, and earthy flavor with nutty, crisp, delicate notes..

Nutritional Benefits:

• Rich in Calcium, iron and phosphorus, the antioxidant sulforaphane and vitamins A and C
• Excellent source of fiber, calcium, magnesium, iron, and other essential minerals
• Cardiovascular health, anti-inflammatory, immunity booster, digestive health, helps prevent cancer, promotes skin brain and respiratory health.

3. Equipment & Materials

3.1 Tray Systems Overview

We offer two specialized tray systems designed for your growing scale:

• 1122 Tray System (Professional-Grade):
  • Usage: Ideal for urban vertical farms and professional growers.
  • Design: A three-tray system consisting of:
    • A bottom reservoir tray that holds water for bottom watering.
    • A growing tray with holes for filling with compost.
    • A top reservoir tray that serves as a cover.
  • Functionality:
    • The bottom tray delivers water via capillary action through the holes in the growing tray.
    • The top tray creates a blackout/humidity dome, ensuring even moisture and optimal germination.
  • Dimensions: 56cm x 28cm x 3cm (22" x 11" x 1 3⁄8")
  • Materials: BPA-free recycled food grade PP; heavy-duty injection moulded
  • Weight: 350g per tray
• Home Professional Tray Set (For Part-Time/Home Growers):
  • Usage: Ideal for home growers, this tray set fits neatly on windowsills and counters, with a 6cm depth that retains moisture better than larger commercial trays, ensuring simpler, hassle-free harvests.
  • Design: Comprised of three BPA-free, recycled plastic trays made in England that mimic commercial growing techniques in a compact size.
  • Dimensions: 22cm x 17cm x 6cm
  • Materials: BPA-free recycled food grade PP; heavy-duty injection moulded
  • Weight: 104g per tray
  • Drainage: Two-tiered drainage holes for optimum moisture control
  • Capacity & Setup:
    • Bottom Tray Capacity: 1200ml
    • Use 1 × 10cm coco discs with 400ml water or half a 650g coco brick to fill the trays perfectly.
  • Key Benefits:
    • The 6cm tray depth (versus 3cm in the professional system) helps maintain consistent moisture and easier maintenance—ideal for part-time growers.
    • Enables cultivation of a wide variety of microgreens in a compact, user-friendly system.

3.2 Seeding Rates & Container Guidelines

• Home Professional Tray Set: Recommended seeding density is 4g of organic broccoli calabrese seeds per tray. A sparser rate produces larger leaves; heavier seeding increases stem proportion.
• 1122 Tray System (Professional): Recommended seeding density is 15g of alfalfa seeds per tray. Heavier seeding results in more stems with smaller leaves.
• Important Considerations: The provided weights (4g and 15g) are on the safer side to manage humidity and reduce crop failure risks. Heavier seeding may increase mold risk however commercial cultivators seed considerably heavier

3.3 Vertical Growing & Rack Setup

Growing microgreens vertically saves space and allows for year-round production with LED lighting. Here’s how to set up an efficient vertical rack system for optimal growth.:

• Choosing Your Rack:
  • Use sturdy, vertical shelving (e.g., kitchen wire-style racks) that allow for easy cleaning and optimal airflow.
  • Ideal rack size: 122cm wide x 45cm deep, fitting four 1122 trays per shelf.
  • Ensure the rack matches your tray dimensions for maximum efficiency.
• Rack Dimensions & Configuration:
  • Standard Rack Size: 122cm (width) x 45cm (depth)
  • Shelves: Typically 6 adjustable shelves per rack.
  • Tray Capacity Per Shelf: 4 trays; with 6 shelves, a rack can hold up to 24 trays.
• LED Lighting Setup:
  • Recommended: Two Barrina LED grow lights per shelf (or two Arize lynk LED for professional setups).
  • Installation: Space lights evenly to cover all trays.
  • Spacing & Positioning:
    • Shelves should be evenly spaced for optimal light and airflow.
    • LEDs should be 20–30cm above the trays.
    • Position warmer climate crops higher and cooler-loving varieties lower.
• Environmental Optimization:
  • Air Circulation: Use a small oscillating fan to reduce mold risk.
  • Temperature Control: Maintain 18–24°C with around 50% relative humidity.

4. Growing in Soil Using Our Tray Systems

Step 1: Preparing Your Growing Container

• Selecting the Tray:
  • Home Growers: Choose the Home Professional Tray Set for its compact size and excellent moisture retention. (Two reservoir, one growing tray)
  • Professional Growers: Use the 1122 Tray System to maximize yield with bottom watering. (Two reservoir, one growing tray)
• Container Preparation: Ensure the tray is clean and free of residues before adding compost, coco, or a grow mat.

Step 2: Soil Preparation

• Choosing Your Medium: Use high-quality coco coir, grow mats, or a nutrient-rich compost mix. Always ensure your coco is LOW “EC” which has been cleaned of its salt content.
• Hydrating Coco Coir:
  1. Unpack & Place: Remove the compressed coco coir block and place it in a bucket or container.
  2. Add Lukewarm Water: Slowly pour water (20–30°C) over the block.
  3. Soak & Expand: Let it soak for 15–30 minutes until it expands.
  4. Fluff: Break up clumps and fluff until even and light.
  5. Mix Nutrients: Stir in organic trace minerals and seaweed powder. (For more details, click here.)
• Filling the Tray: Fill your tray to the rim with the prepared medium and gently tamp down before sowing your seeds. Your coco or compost should be damp but not waterlogged or soggy.

Step 3: Sowing the Seeds

• Measuring & Distributing:
  • Home Professional Tray Set: Use approximately 4g of broccoli seeds per tray.
  • 1122 Tray System: Use approximately 16g of broccoli calabrese seeds per tray.
• Sowing Technique: Evenly spread the seeds over the soil surface—each seed spaced about one to two seed lengths apart.

Step 4: Establishing a Humid Environment and Stacking Procedure

1. Initial Misting: Gently mist the seeds with a spray bottle to settle them into the compost.
2. Assembling the Three-Tray System:
   • Bottom Reservoir Tray: Provides bottom watering via capillary action—fill with water after germination begins.
   • Growing Tray: Place the growing tray (with holes and filled with compost) into the bottom reservoir.
   • Top Reservoir Tray: Stack on top the growing tray to create a blackout/humidity dome. Place it upright with the base of the tray pushing directly down onto the seeds in the growing tray below
3. Applying Weight for an Even Canopy: Place a clean, heavy object (e.g., canned goods) on top to force roots into the compost.
4. Blackout and Stretch: (Optional) Leave lights off extra days to encourage stem elongation.
5. Maintaining Environmental Conditions:
   • Keep relative humidity around 50% and temperature between 18–24°C.
   • Use a fan to improve airflow during the 2–3-day critical germination phase.

Step 5: Light Exposure & Growth Management

• Light Requirements: Once germination occurs (typically 1–3 days), remove the cover and expose microgreens to bright, indirect light or LED grow lights.
• Airflow & Temperature: Maintain gentle airflow and stable temperatures (18–24°C) to prevent mold and promote growth.
• Rotation: Rotate the tray periodically to ensure even light distribution.
• Misting and Care: Mist generously until germination; thereafter, water only via the bottom reservoir and only when needed.

Imagery/Video Guidance:

• Video: A time-lapse video documenting growth under proper lighting conditions.

Step 6: Harvesting & Post-Harvest Handling

• Harvest Timing: Harvest when microgreens reach full colour and optimal size (typically 7–11 days).
• Cutting Technique: Use clean, sharp scissors or a knife to cut just above the soil level.
• Post-Harvest Care: Store harvested microgreens in an airtight container in the fridge; avoid excess moisture.

Imagery/Video Guidance:

• Photo: A series of images capturing the harvesting, rinsing, and drying stages.
• Video: A detailed tutorial on proper harvesting techniques and post-harvest care.

5. Tray Systems: In-Depth Product Details

5.1 1122 Tray System for Professional Growers

• Design:
  • Bottom Reservoir Tray: Holds water for bottom watering; water wicks upward uniformly.
  • Growing Tray with Holes: Sits atop the reservoir and is filled with compost.
  • Top Reservoir Tray: Covers the growing tray, creating a blackout/humidity dome.
• Key Features:
  • Dimensions: 56cm x 28cm x 3cm (22" x 11" x 1 3⁄8")
  • Materials: BPA-free recycled food grade PP; heavy-duty injection moulded
  • Weight: 350g per tray
  • Additional Uses: Ideal for bottom watering and integration with automated systems.
• Benefits: Ensures uniform moisture distribution and optimal germination, designed for repeated use in professional or urban vertical farms.

Imagery/Video Guidance:

• Photo: Detailed product images from multiple angles highlighting the three-tray configuration.

5.2 Home Professional Tray Set for Part-Time Growers

• Design & Features:
  • Comprised of three BPA-free, recycled plastic trays made in England.
  • Dimensions: 22cm x 17cm x 6cm
  • Materials: BPA-free recycled food grade PP; heavy-duty injection moulded
  • Weight: 104g per tray
  • Drainage: Two-tiered drainage holes for optimal moisture control
• Setup Details:
  • Bottom Tray Capacity: 1200ml
  • Use one 10cm coco disc with 400ml water per disc or half a 650g coco brick to fill the trays.
• Key Benefits: A commercial sized microgreen growing system for larger harvests. The growing tray (with holes) can be used separately in large scale flood and drain tables or other hydroponic systems.

Imagery/Video Guidance:

• Photo: Lifestyle images of the Home Professional Tray Set in a home kitchen or on a windowsill.
• Video: A comprehensive setup and review emphasizing ease of assembly and durability.

6. Advanced Tips & Best Practices

• Optimizing Seeding Density: Use about 16g per tray for the 1122 system and 4g per tray for the Home Professional Tray Set, or 0.01 g per cm² for recycled containers.
• Harnessing Bottom Watering: Leverage the reservoir design for uniform moisture without overwatering.
• Light & Temperature Management: Use LED grow lights and maintain 18–24°C to for optimum growth.
• Maintaining Optimal Humidity: Aim for around 50% relative humidity to balance moisture and airflow.
• Air Circulation: Use a fan to promote even airflow and reduce mold risks.
• Nutrient Boost: Consider adding organic trace minerals or seaweed powder when prepping trays or as a liquid feed after seed leaves open.
• Experimentation: Optionally, try a blackout period (2–3 days) to assess its effect on stem length and yield.

Insights from Video Reviews: One video emphasizes an efficient stacking procedure that forces roots into the compost by drawing water upward from the bottom reservoir.

7. Common Issues & Troubleshooting

1. Mold & Fungal Growth
   • Mold thrives in moist, stagnant environments.
   • Prevention:
     • Use fans for air circulation.
     • Maintain ~50% humidity and avoid overwatering.
     • Sanitize trays and equipment between grows.
   • Identification: Differentiate fine, white root hairs from web-like mold growth.
   • Remediation:
     • Remove affected areas.
     • Apply a mild hydrogen peroxide solution (1-3%) if necessary.
2. Uneven Germination
   • Ensure seed quality and even distribution.
   • Keep trays level and use a weighted cover during the first 2–3 days.
3. Leggy or Weak Growth
   • Provide adequate lighting (12–16 hours daily) and rotate trays for even growth.
4. Pest Issues
   • Use sterile growing medium and sanitize equipment.
   • If pests appear, use natural deterrents like neem oil or insecticidal soap.
5. Overwatering & Underwatering
   • Overwatering: Look for yellowing leaves and soggy medium.
   • Underwatering: Look for wilting and dry soil.
   • Adjust watering schedules accordingly.
6. Nutrient Deficiencies
   • Use nutrient-rich, sterile growing medium.
   • If deficiencies occur, apply a diluted organic fertilizer as directed.
7. Contamination Risks
   • Practice strict hygiene when handling seeds and microgreens.
   • Use clean, potable water for irrigation.

8. Nutritional Profile & Health Benefits

Broccoli calabrese microgreens (as opposed to broccoli raab) are packed with nutrients, making them an excellent addition to a healthy diet:

• Vitamin A: Supports vision, immune function, and cell growth.
• Vitamin C: Essential for skin health and antioxidant protection.
• Vitamin K: Aids in blood clotting and bone health.
• Calcium: Supports strong bones and muscle function.
• Magnesium: Helps with nerve function and energy production.
• Iron: Essential for oxygen transport.
• Chlorophyll: Provides detoxifying properties.
• Antioxidant Properties: Rich in vitamins C and E to combat oxidative stress. One of the highest in sulfurophane.
• Bone Health Support: Vitamin K, calcium, and magnesium contribute to bone strength.
• Skin Health Enhancement: Vitamins A and C promote collagen production.
• Supports Cardiovascular Health: Flavonoids and antioxidants reduce inflammation.
• Alkalizing Effect: Helps balance the body’s pH levels.

Adding broccoli microgreens to your diet boosts nutrition while enhancing meals like salads, sandwiches, and smoothies with fresh flavor and powerful health benefits..

9. Seed Quality & Sourcing

The success of your microgreen crop starts with high-quality seeds. Consider the following:

• Where to Buy Quality Seeds: Purchase from trusted sources like Grow Sow Greener—known for lab-tested, pathogen-free, high-germination-rate seeds.
• Factors to Consider: Look for seeds with at least an 85% germination rate, ensure purity, and confirm they are lab-tested.
• Storage Recommendations:
  • Store seeds in a cool, dark, and dry place in an airtight container.
  • For long-term storage, refrigerate or freeze unopened packets (note: frequent opening can reduce viability).

10. Culinary Uses & Recipe Ideas

Flavor & Texture:

• Taste: Mild, sweet, and nutty—ideal as a healthy neutral base.
• Texture: Crisp and refreshing; perfect for raw dishes or light cooking.

Serving Suggestions:

• Superfood Salad – Toss broccoli microgreens with mixed greens, cherry tomatoes, avocado, and a lemon-tahini dressing for a nutrient-packed salad.
• Green Power Smoothie – Blend broccoli microgreens with banana, spinach, almond milk, and a touch of honey for a refreshing and energizing smoothie.
• Smoothies & Wraps: Add a crunchy, nutritious boost to your recipes.

Recipe Idea – Acacado Toast With Broccoli Microgreens:

1. Ingredients: For this nutritious avocado toast, you'll need one ripe avocado, two slices of whole-grain or sourdough bread, and the juice of half a lemon for freshness. Drizzle with one tablespoon of extra virgin olive oil, and season with a quarter teaspoon each of sea salt and black pepper. Top with a small handful of broccoli microgreens for a nutrient boost, and if you like a bit of heat, sprinkle on half a teaspoon of red pepper flakes.
2. Instructions: For extra creaminess, add one tablespoon of crumbled feta or goat cheese..

Imagery/Video Guidance:

• Photo: A beautifully plated salad featuring Broccoli microgreens.
• Video: A complete recipe tutorial from ingredient prep to final plating.

11. FAQs About Organic Broccoli Calabrese Microgreens

Q: How long does it take to grow Broccoli microgreens in the UK?

A: They are typically ready for harvest between 7–11 days when grown in soil or coco using our tray systems.

Q: What seeding rate should I use?

A: Approximately 4g per tray for the Home Professional Tray Set and 16g per tray for the 1122 Tray System. For recycled containers, aim for 0.01 g per cm².

Q: Which tray system should I choose?

A: It depends on your scale—Home Professional for compact, home use and the 1122 Tray System for professional or urban vertical farming.

Q: How do I ensure proper moisture without overwatering?

A: Use bottom watering—add water when the bottom reservoir is dry, and avoid overwatering by monitoring tray weight. Dont water untill well afeter germination

Q: What environmental conditions are optimal?

A: For larger setups, maintain 18–24°C and about 50% relative humidity with proper airflow.

12. Conclusion & Next Steps

Growing Broccoli Calabrese microgreens at home is a simple yet rewarding way to boost your diet with fresh, nutrient-rich greens. Whether you're a beginner or an experienced grower, these microgreens thrive with minimal effort, providing a quick, sustainable, and cost-effective way to enjoy homegrown superfoods. By growing your own, you reduce food waste, cut down on plastic packaging, and enjoy fresher, healthier greens straight from your countertop or vertical setup.

Next Steps:

• Choose your organic seeds, the tray system and growing media that best fits your growing needs.
• Follow the detailed steps to prepare, sow, and nurture your microgreens.
• Experiment with advanced techniques to optimize yield and flavor.
• Enjoy our recipe ideas and share your successes with our growing community!

Imagery/Video Guidance:

• Photo: An inspiring final image of a bountiful tray of organic broccoli microgreens ready to be enjoyed.
• Video (Optional): A closing message featuring community feedback and user success stories.