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

Yes, you can absolutely grow microgreens indoors with great success, making them an ideal choice for year-round fresh produce regardless of outdoor climate or garden space. Growing microgreens indoors is a rewarding and relatively simple process that requires minimal space and equipment, allowing you to harvest nutritious, flavorful greens in as little as one to three weeks. Their quick growth cycle and small footprint make them perfect for urban dwellers, apartment living, or anyone seeking to incorporate more fresh greens into their diet.

What exactly are microgreens?

Microgreens are young vegetable greens that are harvested just after the first true leaves have emerged, typically within one to three weeks of planting, depending on the variety. They are distinct from sprouts, which are germinated seeds eaten whole (seed, root, and shoot), and baby greens, which are more mature and harvested at a later stage. Microgreens are prized for their concentrated flavors, vibrant colors, and exceptionally high nutritional content, often containing more vitamins, minerals, and antioxidants than their mature counterparts. They are typically used as a garnish, an ingredient in salads, or added to sandwiches and smoothies.

Why are microgreens perfect for indoor growing?

Microgreens are perfectly suited for indoor growing due to several key characteristics that align well with an indoor environment. Their specific growth habits and requirements make them an ideal choice for anyone looking to cultivate fresh produce without the need for an outdoor garden or extensive space. This makes them accessible to urban dwellers, apartment residents, or those in colder climates.

Here's why they are so well-suited for indoor cultivation:

• Compact Size: Microgreens are harvested at a very young stage, meaning they don't require much space. You can grow a significant amount of greens in small trays on a windowsill, a shelf, or even a countertop. This minimal footprint is ideal for limited indoor areas.
• Rapid Growth Cycle: Their quick turnaround time is a huge advantage. Most varieties are ready for harvest in 1-3 weeks. This allows for continuous harvests throughout the year, providing a steady supply of fresh greens without long waiting periods. This speed also means that the plants don't require extensive root systems or complex nutrient programs.
• Simple Requirements: Microgreens have relatively simple needs. They don't require deep soil, complex fertilization regimens, or extensive pest control measures, which are often challenging for indoor gardening. Their primary needs are a shallow growing medium, adequate light, and consistent moisture.
• Controlled Environment: Growing indoors gives you complete control over environmental factors like light, temperature, and humidity. This consistency minimizes variables like pests, diseases, and unpredictable weather that can plague outdoor gardens. A controlled environment ensures optimal growth conditions for a reliable harvest.
• No Outdoor Space Needed: This is the most obvious benefit. Even if you live in an apartment with no yard, or during seasons when outdoor gardening is impossible, you can still enjoy fresh, home-grown produce.
• Pest and Disease Resistance (Relative): While not entirely immune, the short growth cycle of microgreens means they are less susceptible to severe pest infestations or disease outbreaks compared to mature plants. Any issues can often be addressed quickly or by simply starting a new batch.
• Minimal Mess: Compared to traditional indoor potting or gardening, microgreen cultivation is relatively clean. The shallow trays and contained growing medium reduce soil spillage and general mess.

These combined factors make microgreens an exceptionally convenient, efficient, and rewarding crop for indoor cultivation, perfectly aligning with the needs and limitations of indoor gardening.

What equipment do I need to grow microgreens indoors?

To successfully grow microgreens indoors, you'll need some basic equipment, most of which is affordable and readily available. You don't need a huge setup to get started; a simple kit can yield plenty of fresh greens.

Here's a breakdown of the essential equipment:

1. Growing Trays:
   • You'll need shallow trays, typically 10 inches by 20 inches (standard nursery flats) or smaller household containers.
   • Two types of trays are often used:
     • Drainage Trays: These have drainage holes and are where your growing medium and seeds will be placed.
     • Bottom Trays (No Holes): These are slightly larger and without holes. They are used to catch excess water from the drainage trays and can also be used for bottom watering.
   • True Leaf Market Microgreens Trays are a popular and reliable choice.
2. Growing Medium (Soil):
   • A fine-textured, sterile, and well-draining potting mix is crucial. Avoid heavy garden soil, which can compact and harbor pathogens.
   • Look for specific "seed starting mix" or "microgreen potting mix." Peat-based or coco coir-based mixes work well.
   • Ensure the mix is loose and free of large chunks.
3. Microgreen Seeds:
   • This is the most important component! Not all seeds are suitable for microgreens. You need specific microgreen seeds that are typically grown for this purpose. They are generally sold in larger quantities than regular garden seeds.
   • Popular varieties include:
     • Leafy Greens: Arugula, kale, mustard, broccoli, radish, cabbage, collards, cress, beet, basil.
     • Herbs: Cilantro, dill, fenugreek.
     • Grains: Wheatgrass, oat.
   • Always choose seeds labeled specifically for microgreens, or look for untreated, organic seeds to ensure they are free of harmful chemicals. True Leaf Market Organic Microgreen Seeds offers a wide selection.
4. Light Source:
   • Bright, indirect light from a sunny windowsill might be enough for some varieties, but for consistent, vigorous growth and good color, supplemental grow lights are highly recommended, especially during shorter, darker months.
   • LED grow lights are energy-efficient and come in various forms (strip lights, panel lights). Look for full-spectrum lights.
   • A simple shop light fixture with cool white or full-spectrum fluorescent bulbs can also work.
   • Barrina T5 LED Grow Lights are popular for their affordability and effectiveness.
5. Spray Bottle or Watering Can with Fine Rose:
   • A fine mist sprayer is essential for initial watering and keeping seeds moist during germination.
   • A small watering can with a very fine rose (sprinkler head) is good for gentle watering once seedlings emerge, preventing soil disturbance.
6. Optional but Recommended:
   • Weight for Germination: A second tray (same size) and a small weight (like a brick or another tray filled with rocks) to place on top of your planted seeds during the blackout period. This encourages stronger root development and uniform germination.
   • Heat Mat: If your indoor environment is consistently cool (below 65°F or 18°C), a seedling heat mat can speed up germination, especially for slower varieties. Hydrofarm Seedling Heat Mat is a reliable brand.
   • Small Fan: A small fan can improve air circulation, helping prevent damping-off disease.
   • Shears or Scissors: For harvesting.

With these basic items, you'll be well-equipped to start your indoor microgreen garden!

What are the best microgreen varieties to grow indoors?

When starting your indoor microgreen garden, choosing the right varieties can make a big difference in your success and enjoyment. Some microgreens are easier to grow, germinate faster, and are more forgiving for beginners.

Here are some of the best microgreen varieties to grow indoors, categorized by ease of growth and popular uses:

Great for Beginners (Fast & Easy):

These varieties are typically quick to germinate, grow rapidly, and are less prone to issues.

• Radish (e.g., 'Sango', 'Daikon'):
  • Flavor: Spicy, peppery.
  • Growth: Very fast, often ready in 5-8 days. Reliable germinators.
  • Appearance: Often colorful stems (like purple 'Sango').
  • Why they're great: Quick gratification, robust flavor.
• Broccoli:
  • Flavor: Mild, slightly cabbage-like.
  • Growth: Fast, ready in 7-10 days. High yield.
  • Why they're great: Highly nutritious, very reliable.
• Arugula:
  • Flavor: Peppery, nutty.
  • Growth: Fast, ready in 7-12 days.
  • Why they're great: Adds a gourmet touch, easy to grow.
• Kale (e.g., 'Red Russian', 'Siberian'):
  • Flavor: Mild, earthy.
  • Growth: Fast to medium, ready in 8-14 days.
  • Why they're great: Super nutritious, good texture.
• Mustard (e.g., 'Spicy Mix', 'Red Giant'):
  • Flavor: Pungent, spicy.
  • Growth: Very fast, often 6-10 days.
  • Why they're great: Quickest results, adds a kick.
• Cabbage (e.g., 'Red Acre'):
  • Flavor: Mild, slightly sweet.
  • Growth: Fast, 8-12 days.
  • Why they're great: Reliable, good bulk.

Moderate Difficulty / Longer Grow Times:

These might require a bit more patience or specific conditions.

• Basil:
  • Flavor: Classic sweet, aromatic basil.
  • Growth: Slower, typically 14-21 days. Benefits from bottom heat for germination.
  • Why they're great: Adds intense herbaceous flavor to dishes.
• Cilantro:
  • Flavor: Strong, fresh cilantro taste.
  • Growth: Slower, 14-21 days. Benefits from pre-soaking seeds.
  • Why they're great: Essential for many cuisines.
• Beet (e.g., 'Detroit Dark Red'):
  • Flavor: Earthy, sweet.
  • Growth: Moderate, 10-20 days.
  • Appearance: Beautiful red stems.
  • Why they're great: Adds color and unique flavor.
• Swiss Chard:
  • Flavor: Mild, earthy.
  • Growth: Moderate, 10-20 days.
  • Appearance: Often colorful stems.
  • Why they're great: Similar to beet greens but often more vibrant.

Considerations When Choosing:

• Soaking: Some seeds (like cilantro, beets, chard, and peas) benefit from pre-soaking for 4-12 hours to improve germination rates.
• Mucilaginous Seeds: Some seeds (like chia, arugula, basil, cress) release a gel-like substance when wet. These are called mucilaginous seeds. They should not be pre-soaked and should be misted very gently to avoid clumping.
• Flavor Profile: Think about how you'll use your microgreens. Do you want something spicy, mild, or herbaceous?
• Nutrition: All microgreens are nutritious, but some (like broccoli and kale) are particularly known for their health benefits.

By starting with the easier varieties, you'll gain confidence and experience, paving the way for trying more diverse microgreen types in your indoor garden.

Step-by-step guide to growing microgreens indoors

Growing microgreens indoors is a straightforward process, making it an excellent project for both novice and experienced gardeners. By following these simple steps, you can ensure a successful harvest of your fresh, nutritious greens.

1. Prepare Your Trays:

   • Take your growing tray (the one with drainage holes).
   • Fill it evenly with about 1 inch to 1.5 inches of your chosen seed starting mix or microgreen potting mix. Don't fill it to the very top.
   • Gently smooth the surface of the soil with your hand or a flat tool. Don't compact it too much, but make sure it's level.

2. Sow the Seeds:

   • Sow seeds densely and evenly across the entire surface of the soil. This is where microgreens differ from regular gardening – you want a thick mat of seedlings.
   • Avoid clumping the seeds. Use a salt shaker or your fingers to distribute them.
   • Do not cover the seeds with soil (unless the specific seed variety recommends it, which is rare for microgreens).

3. Water Gently:

   • Lightly mist the sown seeds and soil surface with a spray bottle. You want the seeds to be moist but not floating in puddles.
   • For mucilaginous seeds (like arugula, basil, cress), mist extra gently to avoid dislodging the gelatinous coating.

4. Blackout/Germination Period (Optional but Recommended):

   • Place another empty growing tray (or a heavier object like a brick wrapped in plastic) directly on top of the seeds. This provides a blackout period and gentle pressure.
   • The darkness encourages germination, and the weight helps the seedlings develop strong root systems by forcing them to push down into the soil.
   • Keep the trays in a warm spot (ideally 65-75°F or 18-24°C). If your room is cooler, a seedling heat mat can be very helpful.
   • This blackout period usually lasts for 2-5 days, depending on the seed variety. Check daily for signs of germination (tiny white sprouts).
   • Keep the soil moist during this time by occasionally lifting the top tray and misting lightly if needed.

5. Expose to Light:

   • Once you see tiny sprouts pushing up (they will look pale and yellow due to lack of light), remove the top tray and weight.
   • Immediately place your trays under your grow lights. Position the lights 2-4 inches above the seedlings.
   • Run the grow lights for 12-16 hours per day. A simple timer can automate this.
   • The light will quickly cause the pale sprouts to turn vibrant green as they start photosynthesis.

6. Water During Growth:

   • From this point on, it's best to bottom water your microgreens. Place the drainage tray (with the microgreens) into a bottom tray (without holes) filled with about 1/2 inch of water.
   • The soil will wick up the water from the bottom. This prevents disturbing the tiny seedlings and reduces the risk of damping-off disease.
   • Remove the tray from the water once the top of the soil appears moist.
   • Water when the soil surface starts to look dry. The frequency will depend on your environment.

7. Ensure Air Circulation (Optional but Recommended):

   • A small fan circulating air near your microgreens can help strengthen stems and prevent fungal issues like damping-off. Ensure it's not blowing directly on the plants.

8. Harvest Your Microgreens:

   • Microgreens are typically ready for harvest when they have developed their first set of true leaves, which are the second set of leaves that appear after the initial cotyledons (seed leaves). This usually happens within 7-21 days, depending on the variety.
   • Use clean, sharp scissors or shears to cut the stems just above the soil line.
   • Harvest what you need and store any remaining harvested greens in an airtight container in the refrigerator for a few days.
   • Most microgreens are a "cut-and-come-again" crop; you get one harvest from each sowing. After harvesting, discard the spent soil and roots and start a new batch.

By following these steps, you'll be enjoying fresh, homegrown microgreens in no time!

How much light do microgreens need indoors?

Light is a critical factor for successfully growing microgreens indoors, arguably one of the most important elements after consistent moisture. While some sources might suggest a sunny windowsill is enough, for vibrant color, robust growth, and optimal nutritional value, supplemental grow lights are highly recommended, and often essential, especially during darker months or if you don't have a truly south-facing, unobstructed window.

Here's why light is so important and how much they need:

• Chlorophyll Production: Light is directly responsible for photosynthesis, the process that creates chlorophyll, the green pigment in plants. Without enough light, microgreens will be pale, leggy, and less nutritious – a condition known as etiolation.
• Sturdy Growth: Adequate light encourages strong, upright growth and prevents seedlings from becoming spindly and weak as they stretch for light.

Recommended Light Setup for Indoor Microgreens:

1. Type of Light:

   • LED Grow Lights: These are the most energy-efficient and popular choice for microgreens. Look for full-spectrum LED lights, as these emit light across the entire visible spectrum, mimicking natural sunlight, which is ideal for plant growth. They produce less heat, allowing you to place them closer to the plants.
   • Fluorescent Lights (T5 or T8): High-output T5 or standard T8 fluorescent shop lights with cool white or full-spectrum bulbs can also work well and are a more budget-friendly option.
   • Avoid: Standard incandescent bulbs are not suitable as they produce too much heat and not the right spectrum of light.

2. Light Duration:

   • Microgreens typically need 12 to 16 hours of light per day.
   • Using an automatic timer is highly recommended to ensure consistent light cycles. This mimics natural day-night cycles and helps prevent stress on the plants. BN-LINK Digital Light Timer is a simple and effective choice.

3. Light Intensity and Distance:

   • The lights should be positioned very close to the tops of the seedlings, typically 2-4 inches away.
   • If your seedlings are stretching or looking pale, lower the lights slightly. If you see signs of scorching (brown spots), raise them a bit.
   • The goal is to provide bright, even light across the entire tray to promote uniform growth.

4. Consider a Light Stand:

   • A simple adjustable light stand or shelving unit with lights mounted beneath each shelf allows you to easily adjust the height of the lights as your microgreens grow, ensuring optimal light intensity throughout their short life cycle.

While a sunny window might produce some microgreens, for consistent, high-quality, and nutrient-dense harvests, investing in a proper grow light setup is one of the best decisions you can make for your indoor microgreen garden.

What kind of soil is best for growing microgreens indoors?

The soil (or growing medium) you choose for growing microgreens indoors is very important for successful germination and healthy, rapid growth. Because microgreens are harvested young and don't require deep root systems, a rich, fertile soil isn't as crucial as good texture and sterility.

Here's what to look for and why:

1. Sterile and Disease-Free:
   • This is paramount. Using sterile potting mix or seed starting mix helps prevent fungal issues like damping-off disease, which can quickly wipe out entire trays of tiny seedlings. Garden soil or compost from your backyard is generally not recommended as it can contain weed seeds, pests, or disease pathogens.
2. Fine Texture:
   • Choose a mix that is fine-textured and uniform. This allows for good seed-to-soil contact, which is essential for consistent germination. It also makes it easier for the delicate roots of microgreens to establish.
3. Light and Fluffy:
   • The medium should be light and airy, not dense or compacted. This promotes good aeration for the roots and prevents waterlogging.
4. Good Drainage:
   • Even though microgreens need consistent moisture, the medium must drain well to prevent the roots from sitting in soggy conditions, which leads to root rot.
5. Moisture Retention:
   • While draining well, the medium also needs to retain enough moisture to keep the seeds and young seedlings hydrated between waterings.

Recommended Growing Mediums:

• Seed Starting Mix: This is often the ideal choice. It's formulated to be fine, sterile, and light, perfect for delicate seedlings. Many seed starting mixes are peat-based or coco coir-based.
• Potting Mix (specifically for containers/indoor plants): A general-purpose potting mix can work, but ensure it's a high-quality, light one. Avoid heavy, dense, or cheap potting mixes that contain large wood chunks.
• Coco Coir: Made from coconut husks, coco coir is an excellent, sustainable option. It's sterile, has good water retention, and excellent aeration. It often comes in compressed bricks that expand when water is added. FoxFarm Coco Loco Potting Mix is a popular product.
• Peat Moss: Similar to coco coir in properties, it's also a common base for seed starting mixes. Ensure it's sustainably sourced if that's a concern.

Things to Avoid:

• Garden Soil: Too heavy, can introduce pests, diseases, and weed seeds.
• Compost: While excellent for mature plants, raw compost might be too coarse and contain too many un-decomposed materials or pathogens for delicate microgreens.
• Used Soil: Always use fresh, sterile growing medium for each new batch of microgreens to prevent disease buildup.

Using the right growing medium provides the perfect foundation for healthy, vigorous microgreen growth in your indoor setup.

Can I grow microgreens without soil?

Yes, you can absolutely grow microgreens without soil, using various hydroponic or soilless growing methods. These methods offer advantages such as cleanliness, reduced risk of soil-borne diseases, and often faster growth rates. While some microgreen varieties thrive in soilless systems, others (especially larger-seeded or those needing a bit more support) still perform best in traditional soil.

Here are the most common soilless methods for growing microgreens indoors:

1. Hemp Mats / Grow Mats:
   • How it works: These are natural fiber mats (like hemp, jute, or coco coir) that you simply lay in your growing tray. You moisten the mat, sprinkle your seeds directly on top, and keep them moist. The roots grow into the mat for support and moisture.
   • Benefits: Very clean, no mess, prevents damping-off, good air circulation for roots.
   • Best for: Smaller-seeded microgreens like broccoli, kale, arugula, radish, mustards, cress. They generally don't do as well for larger seeds like peas or sunflowers which prefer a bit more rooting depth.
   • Example: Terrafibre Hemp Grow Mats.
2. Hydroponic Systems (DIY or Kits):
   • How it works: Seeds are sown on a thin layer of inert medium (like rockwool, vermiculite, or perlite) or directly onto a mesh tray. The roots grow into a reservoir of nutrient-rich water or are regularly misted with a nutrient solution.
   • Benefits: Can achieve very fast growth, precise control over nutrients, very clean.
   • Best for: A wide range of microgreens, once you understand the nutrient solution requirements.
   • Considerations: Requires more setup initially (pumps, air stones, nutrient solutions), can be more complex for beginners.
3. Paper Towels:
   • How it works: A very simple, short-term method. Lay a few layers of damp paper towels in a shallow tray, sprinkle seeds, and keep moist.
   • Benefits: Extremely cheap, easy to start.
   • Best for: Very quick-growing, small-seeded varieties like radish or cress for a single, quick harvest.
   • Considerations: Not ideal for longer-growing microgreens as they offer minimal nutrient support. Can dry out quickly.
4. Perlite or Vermiculite:
   • How it works: These are inert, lightweight minerals that provide good aeration and moisture retention. You can sow seeds directly on top or in a thin layer.
   • Benefits: Sterile, good drainage, very light.
   • Considerations: No inherent nutrients, so if you grow for longer than a week, you'll need to add a very diluted hydroponic nutrient solution.

Why consider soilless methods?

• Cleanliness: Less mess, no soil tracking.
• Disease Prevention: Eliminates soil-borne pathogens, reducing risk of damping-off.
• Faster Growth: Often, roots can access water and nutrients more readily.
• Pest Reduction: Fewer places for soil-dwelling pests to hide.

While growing microgreens without soil is entirely possible and often preferred for specific reasons, some larger microgreens like peas or sunflowers, due to their larger seed size and need for more root anchorage, may still thrive better in a shallow layer of a high-quality soil medium. Experimentation is key to finding what works best for you and your chosen varieties.

How do I prevent mold and damping-off in my indoor microgreens?

Mold and damping-off disease are common challenges when growing microgreens indoors, especially for beginners. These fungal issues can quickly decimate an entire tray of seedlings. However, with careful attention to environmental control and sanitation, you can largely prevent them.

Preventing Mold:

Mold (often appearing as fuzzy white, gray, or black growth on the soil surface or seedlings) indicates too much moisture and/or poor air circulation.

1. Improve Air Circulation:
   • Use a small oscillating fan set on a low speed to gently move air around your microgreen trays. This helps evaporate excess moisture from the soil surface and the seedlings. Ensure the fan isn't blowing directly on the plants constantly, which can dry them out.
   • Space your trays out to allow air to flow between them. Avoid stacking trays too closely.
2. Proper Watering:
   • Avoid overwatering. This is the most common cause. Allow the soil surface to dry slightly between waterings.
   • Bottom water your microgreens (as described in the step-by-step guide) once they have germinated. This keeps the foliage dry and only moistens the root zone.
   • Do not mist excessively once seedlings emerge. Only mist during the initial germination phase.
3. Sterile Growing Medium:
   • Always use a fresh, sterile seed starting mix or specific microgreen potting mix for each batch. Never reuse old soil, as it can harbor mold spores.
4. Cleanliness:
   • Thoroughly clean and sanitize your growing trays and any tools before each use. A 10% bleach solution or a commercial plant sanitizing spray works well.
5. Maintain Proper Humidity:
   • While misting is fine initially, once seedlings are up, avoid overly humid environments. Keep your growing area well-ventilated.

Preventing Damping-Off Disease:

Damping-off is a collective term for several fungal diseases that attack young seedlings at or just below the soil line, causing them to suddenly wilt, collapse, and die. It's often seen when seedlings are very young.

1. Sterile Growing Medium:
   • As with mold, always use new, sterile seed starting mix or coco coir.
2. Avoid Overwatering:
   • Excess moisture is the biggest trigger. Ensure good drainage in your trays and practice bottom watering.
3. Good Air Circulation:
   • Use a fan to keep air moving around the seedlings. Stagnant, humid air promotes fungal growth.
4. Appropriate Spacing:
   • While microgreens are sown densely, avoid excessive overcrowding. A little air circulation between seedlings can help.
5. Proper Temperature:
   • Maintain consistent and appropriate temperatures for germination. Extremes can stress seedlings, making them more susceptible.
6. Cleanliness:
   • Always use clean, sanitized trays and tools.
7. Consider a Thin Layer of Vermiculite:
   • After sowing seeds, a very thin layer of vermiculite can sometimes be sprinkled over the seeds. It's sterile and can help create a drier surface environment, though generally, leaving microgreen seeds uncovered is preferred.

If you do encounter mold or damping-off, it's often best to discard the affected tray and start fresh, ensuring you implement these preventative measures for your next batch of indoor microgreens.