Growing microgreens in a greenhouse is a fun, engaging gardening project that offers numerous benefits. Not only does it allow you to stay active and enjoy the outdoors, but it can also turn a small hobby into a profitable side hustle. These tiny plants are incredibly easy to grow, require little space, and yield high returns in a short time and whether you’re growing them for personal use or to sell, microgreens are nutrient-packed and make a powerful addition to smoothies, salads, and sandwiches.

In this blog, we’ll answer your most common questions about growing microgreens in a greenhouse. From essential growing tips to what you need to know before buying seeds, we’ll cover everything to help you decide if this rewarding venture is right for you.

What are microgreens? 

Microgreens are young vegetable or herb seedlings harvested at an early stage, typically between 7 to 21 days after germination. Microgreens seeds come in different types, including leafy greens, root vegetables, and edible flowers that are nutrient-dense and have a very distinct flavor. 

Why grow microgreens in a greenhouse?

Greenhouses provide a controlled environment that allows for year-round production, protection from pests and harsh weather, and optimal growing conditions for consistent growth and quality. Microgreens should generally be grown in seedling trays rather than directly in raised garden beds. Seedling trays provide better control over growing conditions, such as soil depth, moisture, and temperature, allowing for faster germination and more uniform growth. They also help keep the small plants contained and easy to manage.

What are the best microgreens to grow in a greenhouse?

• Arugula

• Basil

• Broccoli microgreens

• Cilantro

• Radish microgreens

• Sunflower

• Pea shoots

• Mustard greens

• Swiss chard

What type of lighting do microgreens need?

Microgreens require adequate light for proper growth. Natural sunlight in a greenhouse can be supplemented with LED or fluorescent grow lights to ensure they receive 12-16 hours of bright light daily. Placing trays near a south-facing window can also provide natural sunlight during winter months.

What temperature is ideal for growing microgreens?

Microgreens thrive in temperatures between 60-75°F (15-24°C) to ensure optimal growth and prevent stress on young plants.

What humidity levels are best for microgreens in a greenhouse?

Relative humidity levels of 40-60% are ideal for microgreens since proper ventilation and air circulation help prevent bacterial growth, mold, and disease in a greenhouse. 

What type of soil is best for growing microgreens?

A light, well-draining soil mix, such as organic potting mix or coconut coir, is best for growing microgreens. Avoid any kind of heavy garden soil, as it may compact and hinder root development and drainage.

Do microgreens need composting or fertilizer?

Microgreens grow quickly and typically do not require additional compost or fertilizer. However, using a nutrient-rich soil can give them the foundation they need to grow strong.

How often should microgreens be watered?

Water microgreens consistently to keep the growing medium moist but not waterlogged. 

What is the best way to water microgreens without overwatering?

Using a spray bottle or cool water misting is an easy way to provide enough hydration without overwatering or adopt the bottom watering method to prevent mold and root rot.

How do you prevent mold and diseases?

• Ensure proper airflow with fans or vents in the greenhouse.

• Avoid overwatering and let excess water drain through drainage holes.

• Use clean trays and sterilized growing mediums.

• Monitor and maintain optimal temperature and humidity levels.

• Use the right soil so proper drainage can happen on the seedling trays. 

How long do microgreens take to grow?

Microgreens typically take 7 to 21 days to reach harvest, depending on the variety. Fast-growing types like radish microgreens and mustard greens are ready in about 7-10 days, while basil and cilantro take closer to 20 days.

How are microgreens harvested?

Harvest in the mornings to ensure maximum freshness and shelf life and use a clean, sharp knife or scissors to cut microgreens just above the soil line. 

Can microgreens be regrown after harvesting?

Most microgreens do not regrow after harvesting since they are cut at an early stage. Some varieties, like pea shoots and wheatgrass, may regrow if left with enough stems and roots.

How should microgreens be stored?

• Rinsed gently and dried thoroughly with paper towels.

• Stored in an airtight plastic bag or container with a paper towel to absorb excess moisture.

• Kept in the refrigerator at 35-40°F (1-4°C) for up to a week.

What are the common challenges in growing microgreens in a greenhouse?

• Mold and fungal diseases due to high humidity.

• Inconsistent light exposure affecting growth.

• Overcrowding leading to poor air circulation.

• Pest issues such as aphids or fungus gnats.

Are microgreens profitable for commercial greenhouse growing?

Yes, microgreens can be highly profitable due to their fast-growing nature, small size, and high market demand, especially in restaurants, grocery stores, and farmers' markets. They offer quick turnover and can be sold at a premium price. However, profitability can depend on finding the right market, particularly if you live in a rural area. Success often involves connecting with local buyers or niche markets, such as health-conscious consumers or gourmet chefs.

What are the health benefits of consuming microgreens?

Microgreens are rich in vitamins, including vitamin C and vitamin E, minerals, and antioxidants. 

When is the best time to grow microgreens?

Microgreens can be grown year-round in a greenhouse or indoors using grow lights. The best time depends on the type of seeds, but many microgreens thrive in controlled growing conditions during winter months when outdoor gardening is limited.

How do microgreens compare to their mature counterparts?

Microgreens often contain higher nutrient levels than their mature plant counterparts. They develop their first set of leaves (seed leaves), followed by the first true leaves, before being harvested as tiny plants with concentrated flavors and health benefits.

Final Thoughts

Growing microgreens requires clarity on your goal—whether for nutritional benefits, personal use, or commercial sale. They need attention to thrive, so commitment is key.

By managing light, water, temperature, and air circulation, you can maximize yield and quality while minimizing challenges. Microgreens are a space-efficient way to grow fresh, nutritious produce, and with the right care and focus, they can easily become a fun and profitable gardening project!