Can I grow microgreens indoors in the outdoor? - Plant Care Guide

While the phrase "grow microgreens indoors in the outdoor" seems contradictory, it highlights a common confusion: can you leverage outdoor conditions for what's typically an indoor crop? The direct answer is yes, you absolutely can grow microgreens outdoors, but it's important to understand that doing so requires careful consideration of environmental factors like sunlight, temperature, pests, and watering. Microgreens are usually grown indoors because it offers more control over these variables, which are crucial for their rapid, tender growth.

What Are Microgreens and Why Grow Them?

Microgreens are young, edible seedlings of various vegetables and herbs, harvested when they are typically 1-3 inches tall, usually within 1-3 weeks of germination. They are distinct from sprouts, which are germinated in water, and baby greens, which are allowed to grow larger. Growing microgreens has become popular due to their concentrated flavor, vibrant colors, and impressive nutritional content, often exceeding that of their mature counterparts.

Reasons to grow microgreens include:

• Nutrient Density: Many microgreens contain significantly higher levels of vitamins, minerals, and antioxidants than mature plants. For example, red cabbage microgreens have 6 times more Vitamin C than mature cabbage.
• Rapid Growth Cycle: From seed to harvest, most microgreens are ready in 7-21 days, allowing for a continuous fresh supply.
• Intense Flavor: They pack a powerful flavor punch, making them excellent additions to salads, sandwiches, smoothies, and garnishes.
• Space-Saving: They require very little space, making them ideal for small kitchens, apartments, or any compact living area.
• Ease of Growing: With minimal equipment and attention, even beginner gardeners can successfully grow microgreens.
• Year-Round Freshness: Typically grown indoors, they provide fresh produce regardless of outdoor weather conditions.

Can Microgreens Really Be Grown Outdoors?

Yes, microgreens can absolutely be grown outdoors, under the right conditions and with proper management. While most popular methods emphasize indoor growing for control, a sunny patio, balcony, or garden spot can be a suitable environment during warmer months. The key is to replicate the controlled environment of indoor growing as much as possible, protecting them from harsh elements and pests.

What are the Benefits of Growing Microgreens Outdoors?

Growing microgreens outdoors offers several distinct advantages that can enhance their growth and simplify your setup.

• Free Sunlight: The most obvious benefit is access to natural sunlight, which is often more intense and comprehensive than artificial grow lights. This can lead to robust growth and vibrant color.
• Excellent Air Circulation: Outdoor environments naturally provide better airflow, which helps prevent common issues like damping-off disease (a fungal problem that affects seedlings) that can be prevalent in humid indoor setups.
• Temperature Regulation (in ideal conditions): During warm, mild weather, outdoor temperatures can be perfect for microgreen growth, negating the need for indoor climate control.
• Reduced Equipment Needs: You may not need to invest in LED Grow Lights or fans, reducing initial setup costs for your microgreen growing kit.
• Access to Rainwater: During gentle rainfall, your microgreens can receive natural, chlorine-free water, which some growers prefer.

What are the Challenges of Growing Microgreens Outdoors?

Despite the benefits, growing microgreens outdoors comes with significant challenges that must be addressed for success. The delicate nature of microgreens makes them vulnerable to various environmental stressors.

• Uncontrolled Temperatures: Microgreens prefer consistent temperatures, typically between 65-75°F (18-24°C). Outdoors, temperatures can fluctuate wildly, leading to slow growth, bolting (premature flowering), or even death during cold snaps or heat waves.
• Pest Infestations: Outdoor environments are teeming with pests like aphids, fungus gnats, slugs, and birds, all of which can quickly devastate a tray of tender microgreens. This is arguably the biggest challenge.
• Harsh Sun Exposure: While sunlight is beneficial, direct, intense sunlight can scorch delicate microgreen seedlings. They often thrive with bright, indirect light or morning sun.
• Inconsistent Watering: Wind and sun can cause outdoor trays to dry out very quickly, necessitating frequent watering. Overwatering can also be an issue during rainy periods, leading to damping-off.
• Contamination: Outdoor growing increases the risk of soil-borne pathogens, dust, and environmental pollutants affecting your edible greens. Using food-grade trays and clean practices is vital.
• Wind Damage: Strong winds can physically damage tender seedlings or dry them out rapidly.
• Weed Seeds: Outdoor soil can introduce weed seeds into your microgreen trays, though this is less of an issue if using a sterile seed-starting mix.

How Can You Prepare an Outdoor Setup for Microgreens?

Preparing an outdoor setup for microgreens requires careful planning to mitigate the inherent challenges of the environment. The goal is to create a sheltered, controlled space that mimics the ideal indoor conditions as much as possible.

What Type of Location is Best Outdoors?

Choosing the right location is paramount for outdoor microgreen success.

• Partial Shade/Morning Sun: Look for a spot that receives 3-5 hours of morning sun and then shifts to partial shade or dappled light in the afternoon. This protects delicate seedlings from the intense midday sun.
• Sheltered from Wind: Choose an area protected from strong winds, such as near a wall, fence, or under a porch. Wind can dry out trays quickly and physically damage plants.
• Easy Access: Place trays where they are easily accessible for daily monitoring, watering, and pest checks.
• Away from Pests: Avoid areas known for heavy pest activity. If possible, keep them elevated off the ground to deter slugs and snails.

What Equipment Do You Need for Outdoor Microgreens?

While you might save on grow lights, specific equipment is still crucial for outdoor microgreen growing.

• Growing Trays: Use shallow, food-grade growing trays with drainage holes, along with corresponding trays without holes to catch excess water. Microgreen Trays with Drainage are ideal.
• Seed Starting Mix: A fine-textured, sterile seed starting mix is essential. Do not use regular garden soil, as it can contain weed seeds, pests, and pathogens. Look for Seed Starting Mix specifically designed for germination.
• Microgreen Seeds: Choose high-quality, untreated microgreen seeds. Popular choices include radish, broccoli, kale, arugula, and various basil varieties. You can find diverse Microgreen Seeds Assortment.
• Watering Can/Spray Bottle: A fine mist from a Misting Spray Bottle or a watering can with a gentle rose is crucial for initial watering without disturbing seeds. For bottom watering, a small watering can works well.
• Dome/Cover (Optional but Recommended): A clear plastic dome or even plastic wrap can help maintain humidity during germination and protect from pests.
• Shade Cloth (Highly Recommended): A piece of Shade Cloth for Plants (around 30-50% shade) is invaluable for protecting seedlings from intense sun.
• Pest Barriers: Consider mesh covers, row covers, or even elevated shelving with fine netting to keep insects and birds away. Fine Mesh Netting can be draped over hoops.

What Are the Steps for Growing Microgreens Outdoors?

The process for growing microgreens outdoors closely mirrors indoor methods but includes additional considerations for environmental protection. Following these steps carefully will increase your chances of a successful harvest.

1. Prepare Your Trays:
   • Fill your shallow trays (with drainage holes) with about 1-1.5 inches (2.5-3.8 cm) of moist, sterile seed starting mix.
   • Lightly tamp down the soil surface to create a level bed.
2. Sow Your Seeds:
   • Broadcast your microgreen seeds densely and evenly over the soil surface. Different seeds have different optimal densities, but a good rule of thumb is enough seeds so they nearly touch but don't overlap too much.
   • Do not cover most microgreen seeds with soil. Some larger seeds (like peas or sunflowers) can be lightly covered with a thin layer of soil.
3. Initial Watering and Blackout:
   • Gently mist the seeds and soil surface with a Misting Spray Bottle until thoroughly moistened.
   • Place a second, empty tray on top of the seeded tray, or use a dome/plastic wrap to create a "blackout" period. This encourages uniform germination and helps seeds root down. Add a light weight on top of the upper tray to gently press the seeds into the soil.
   • Keep trays in a warm, dark place (can be indoors or a sheltered outdoor spot) for 2-4 days, or until germination begins. Check daily for moisture and spray if dry.
4. Exposure to Light (and Protection):
   • Once seeds have germinated and formed tiny rootlets, and some seedlings are pushing up, remove the blackout cover.
   • Move the trays to your chosen outdoor location that receives bright, indirect light or morning sun.
   • Crucially, deploy your shade cloth if intense sun is a risk. Position it to filter the harsh midday rays.
5. Watering During Growth:
   • Once the seeds have germinated and the blackout period is over, switch to bottom watering. Pour water into the solid tray beneath the microgreen tray. The soil will wick up the moisture from below.
   • Check daily, especially on warm or windy days, as outdoor trays can dry out quickly. Empty any standing water after 15-30 minutes if the soil is saturated to prevent damping off.
   • Keep the soil consistently moist, but not waterlogged.
6. Pest and Disease Management:
   • Daily Inspection: This is vital. Check for any signs of pests (tiny bugs, holes in leaves) or diseases (mold, damping off).
   • Pest Barriers: Use Fine Mesh Netting or row covers to create a physical barrier against insects and birds.
   • Organic Pest Control: If pests appear, use a very diluted organic insecticidal soap or neem oil spray, but be aware that strong solutions can harm tender microgreens. Manual removal is often best for small infestations.
   • Good Air Circulation: Ensure your outdoor setup allows for adequate airflow to prevent fungal issues.
7. Harvesting:
   • Microgreens are typically ready for harvest when they develop their first true leaves (the second set of leaves after the initial cotyledons). This is usually between 7-21 days after planting, depending on the variety.
   • Use sharp Kitchen Shears or a clean, sharp knife to cut the microgreens just above the soil line.
   • Harvest only what you need, as freshly cut microgreens taste best. Rinse gently before use.

What Are the Best Microgreen Varieties to Grow Outdoors?

When selecting microgreen varieties for outdoor growing, it's wise to choose those that are generally robust, grow quickly, and can tolerate slight variations in outdoor conditions. While many varieties can work, some are more forgiving than others.

• Radish Microgreens: These are super fast growers (often ready in 5-10 days) and have a peppery kick. They are quite hardy and tolerate a range of light conditions. Popular varieties include Sango (red) and China Rose.
• Broccoli Microgreens: Very popular for their high nutritional content, broccoli microgreens are relatively easy to grow and grow quickly. They prefer consistent moisture and good airflow.
• Arugula Microgreens: Known for their pungent, peppery flavor, arugula grows quickly and is relatively resilient outdoors.
• Kale Microgreens: Like broccoli, kale microgreens are nutrient powerhouses. They are generally adaptable but prefer milder temperatures.
• Mustard Microgreens: If you like a spicy kick, mustard varieties grow very fast and are quite sturdy.
• Cress Microgreens: Watercress and garden cress are fast-growing and prefer consistent moisture, making them suitable if you can manage watering effectively outdoors.
• Pea Shoots: These are larger than typical microgreens but follow a similar growth process. They are incredibly easy to grow, very hardy, and require simple care. Pea shoots are less prone to damping off and tolerate a wider range of conditions. Use special Pea Microgreen Seeds.
• Sunflower Microgreens: Another larger microgreen, sunflower shoots are sturdy and have a delightful nutty flavor. They are also quite hardy outdoors, though they require specific preparation (soaking seeds) and can be prone to mold if humidity is too high.
• Basic Lettuce Varieties: Butterhead or romaine lettuce varieties can be grown as microgreens for a mild, leafy addition. They are generally forgiving.

Varieties to be cautious with outdoors (but still possible with extra care):

• Basil Microgreens: While delicious, basil can be more susceptible to cold temperatures and fungal issues if air circulation isn't optimal.
• Cilantro Microgreens: Also sensitive to extreme temperatures and can bolt (go to seed) quickly in hot weather.

The key to success with any variety outdoors is constant vigilance and adaptation to the changing environmental conditions.