How to Grow Microgreens in Mason Jars at Home: Complete Beginner's Guide
By Bryan, Microgreens Farmer at Wind River GreensQuick answer: You can grow fresh, nutrient-packed microgreens in mason jars at home in just 7-14 days with a setup that costs under $20. All you need is a wide-mouth mason jar, seeds, and a sunny windowsill — no special equipment required. It's one of the most beginner-friendly ways to grow food indoors, even in a small apartment.
Growing microgreens in mason jars is one of the easiest and most space-efficient ways to start your indoor gardening journey. This method requires minimal equipment, takes up hardly any counter space, and produces fresh, nutrient-packed greens in just 7-14 days.
Whether you're living in a small apartment, want to garden year-round, or simply love the idea of growing food in repurposed containers, mason jar microgreens are perfect for beginners. You'll have fresh greens ready to harvest in less than two weeks, and the whole setup costs under $20.
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What Makes Mason Jars Perfect for Microgreens?
Mason jars offer several advantages that make them ideal containers for growing microgreens at home. The clear glass allows you to monitor root development and water levels easily, while the wide mouth provides excellent access for planting, watering, and harvesting.
The compact size means you can fit multiple jars on a windowsill or countertop without taking over your kitchen. Plus, mason jars are incredibly affordable and likely something you already have at home.
Unlike traditional growing trays, mason jars create a semi-hydroponic environment that many microgreen varieties absolutely love. The contained system also reduces mess and makes the whole process more manageable for beginners.
Best Microgreen Varieties for Mason Jar Growing
Not all microgreens thrive in mason jars, so choosing the right varieties is crucial for success. Some varieties work better than others due to their root structure, growth patterns, and space requirements.
Excellent choices for mason jars:
- Broccoli microgreens: Fast-growing, compact, and produce excellent yields
- Radish microgreens: Quick germination and vibrant colors
- Alfalfa: Classic choice that grows beautifully in jars
- Mung bean sprouts: Traditional jar growing method
- Clover: Delicate and flavorful
Varieties to avoid in jars:
- Sunflower microgreens: Too large and need more horizontal space
- Pea shoots: Require deeper growing medium
- Wheatgrass: Better suited for flat trays
At Wind River Greens, we've found that smaller-seeded varieties consistently perform better in mason jar setups. The key is matching the variety to the growing space.
Materials You'll Need
Gathering your supplies is straightforward and inexpensive. Most items can be found at your local grocery store or online, and many you might already have at home.
Essential supplies:
- Wide-mouth mason jars (16 oz or larger work best)
- Sprouting lids or cheesecloth with rubber bands
- High-quality microgreen seeds
- Clean water (filtered preferred)
- Small bowl for soaking seeds
Optional but helpful:
- Paper towels for extra moisture control
- Labels for tracking varieties and planting dates
- Spray bottle for gentle watering
The sprouting lids are worth the small investment as they provide better drainage and air circulation than makeshift alternatives. However, cheesecloth secured with rubber bands works fine for getting started.
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Step-by-Step Growing Process
Step 1: Prepare Your Seeds
Start by measuring your seeds carefully. For most varieties, you'll want about 1-2 tablespoons of seeds per mason jar, though this varies by seed size and variety.
Place seeds in a small bowl and rinse them thoroughly with cool water. Remove any debris, broken seeds, or anything that looks off. Quality seeds are essential for successful microgreens.
Some larger seeds benefit from a brief soaking period (2-4 hours), while smaller seeds like broccoli can go directly into the jar. When in doubt, check the specific requirements for your chosen variety.
Step 2: Initial Soaking and Setup
Add your prepared seeds to the mason jar and cover with cool, filtered water. Use about 2-3 times as much water as you have seeds to allow for proper hydration.
Secure your sprouting lid or cheesecloth cover and let the seeds soak for the recommended time. Most microgreen seeds need 4-8 hours of soaking, though some varieties require longer.
After soaking, drain the water completely through the lid. Rinse the seeds once more with fresh water, then drain again. This removes any residual debris and starts the sprouting process.
Step 3: Create the Perfect Environment
Place your jar at a slight angle in a bowl or dish to ensure proper drainage. The seeds should rest against one side of the jar, creating more surface area for sprouting.
Store the jar in a dark, warm location for the first 2-3 days. A kitchen cabinet or pantry works perfectly. The ideal temperature range is 65-75°F for most varieties.
During this initial period, rinse and drain the seeds twice daily - morning and evening. This prevents mold and keeps the seeds properly hydrated.
Step 4: Transition to Light
Once you see small sprouts emerging (usually day 2-3), it's time to introduce light. Move your jars to a bright location with indirect sunlight, such as a north-facing windowsill.
Continue the twice-daily rinsing routine, but now you can start reducing the frequency as the microgreens develop. Watch for signs of the cotyledon leaves (seed leaves) beginning to open.
The microgreens will start developing their characteristic green color once exposed to light. This process, called "greening," typically takes 2-3 days.
Step 5: Monitor Growth and Harvest
Your microgreens are ready to harvest when they've developed their first true leaves and reached 1-3 inches in height. This usually happens 7-14 days after planting, depending on the variety.
To harvest, simply cut the microgreens just above the root level using clean scissors. Harvest only what you need, as cut microgreens are best used fresh.
The remaining microgreens will continue growing for a few more days, giving you multiple harvests from one planting.
Troubleshooting Common Issues
Even with the best intentions, you might encounter some challenges when growing microgreens in mason jars. Here are the most common problems and their solutions.
Mold growth: Usually caused by too much moisture or poor air circulation. Increase rinsing frequency and ensure proper drainage. Make sure your sprouting lid allows adequate airflow.
Slow or poor germination: Often due to old seeds, incorrect soaking time, or temperature issues. Always use fresh, high-quality seeds and maintain consistent temperatures.
Leggy or pale growth: Indicates insufficient light exposure. Move jars to a brighter location, but avoid direct sunlight which can create too much heat.
Seeds not sprouting uniformly: This is normal and expected. Some seeds naturally germinate faster than others, even within the same variety.
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Maximizing Your Harvest
To get the most from your mason jar microgreens, timing and technique matter. Stagger your plantings by starting new jars every 3-4 days to ensure a continuous harvest of fresh greens.
Keep detailed records of which varieties work best for you and note the optimal harvest timing. Each variety has its peak flavor and texture window, and finding that sweet spot takes a little experimentation.
Consider growing multiple varieties simultaneously to create your own custom microgreen mixes. Combining mild varieties like broccoli with spicier ones like radish creates interesting flavor profiles.
Storage and Usage Tips
Fresh-harvested microgreens are delicate and should be used quickly for best quality. Rinse gently in cool water just before use and pat dry with paper towels.
Store unharvested microgreens in the refrigerator for 2-3 days maximum. Cut microgreens should be used within 24 hours for optimal freshness and nutrition.
These homegrown microgreens are perfect for sandwiches, salads, smoothies, and garnishing soups. Their intense flavors mean a little goes a long way.
Scaling Up Your Operation
Once you've mastered mason jar microgreens, you might want to expand your growing capacity. Multiple jars allow you to experiment with different varieties and maintain a steady supply.
Consider dedicating a specific area of your kitchen or a spare room to your microgreens operation. Good lighting and easy access to water will make the process much more efficient.
As you gain experience, you might want to explore other growing methods like traditional trays or hydroponic systems, building on the foundation you've established with mason jars.
Step-by-Step Growing Instructions
Once you have your supplies ready, the actual process is straightforward. The most important thing to understand is that mason jar microgreens go through two distinct phases: a sprouting phase where you're essentially making sprouts, and a greening phase where the seedlings develop their first true leaves and chlorophyll.
Day 1-2: Soaking Your Seeds
Start by measuring out your seeds. For a standard 16 oz wide-mouth mason jar, use 1-2 tablespoons of small seeds like broccoli, radish, or alfalfa. Mung beans are larger, so 3-4 tablespoons works better for those.
Rinse the seeds thoroughly with clean water, then cover them with 2-3 times their volume of water and let them soak for 8-12 hours. Broccoli and radish seeds do well with an 8-hour soak. Mung beans benefit from a full 12 hours. Don't soak alfalfa or clover for more than 6-8 hours — they can get waterlogged.
Day 2-5: The Sprouting Phase
After soaking, drain the seeds completely and place the jar upside down at a 45-degree angle in a bowl or dish rack. This drainage position is critical. Seeds sitting in standing water will rot within 24 hours. Keep the jar away from direct sunlight during this phase — a countertop or cabinet shelf works well.
Rinse and drain the seeds twice daily, morning and evening. Each rinse should be thorough: add water, swirl gently, and drain completely. You'll start seeing small white tails emerge from the seeds within 24-48 hours. That's exactly what you want.
Day 5-7: Moving to Light
Once your sprouts are showing visible growth and fill roughly a third of the jar, move them to a bright windowsill with indirect light. South-facing windows work best in the northern hemisphere. The seedlings will begin turning green within 12-24 hours of light exposure. At this stage, continue rinsing once daily rather than twice.
Keep the jar upright or at a slight angle during this phase. The goal now is even light exposure and continued drainage to prevent moisture buildup at the bottom.
Common Mistakes That Kill Mason Jar Microgreens
Most failed batches come down to a handful of preventable errors. Knowing what to watch for saves a lot of frustration.
Insufficient Drainage
This is the number one problem. If water sits at the bottom of the jar for more than 30 minutes after rinsing, you're going to see mold within a few days. Always drain thoroughly, and make sure your jar is angled correctly. A sprouting lid with mesh allows much better drainage than cheesecloth alone — it's one of the few supplies worth spending a few extra dollars on.
Overseeding
More seeds does not mean more yield. When seeds are packed too tightly, air circulation drops, moisture builds up between the seeds, and mold spreads quickly. For broccoli or radish in a 16 oz jar, 1.5 tablespoons is plenty. You can always grow a second jar alongside the first if you want more volume.
Skipping the Rinsing Schedule
Missing even one rinse during the sprouting phase can cause problems. The rinsing does two things: it keeps seeds hydrated and it removes metabolic waste products that encourage bacterial growth. Set a phone reminder if you need to — twice daily for days 2-5, once daily after that.
Using Low-Quality Seeds
Not all seeds are created equal for this purpose. Garden seeds treated with fungicides or pesticides are not meant for eating at the sprout stage. Always use seeds specifically labeled for sprouting or microgreens. Germination rate matters too — old seeds with low viability will give you patchy, inconsistent results. Look for seeds with a germination rate of 90% or higher.
Too Much Direct Sun Too Soon
Intense direct sunlight during the early sprouting phase dries seeds out quickly and can overheat the jar. Wait until seedlings have visible green shoots before placing them in a south-facing window. During summer months, east-facing windows that get morning light are actually gentler and work well throughout the entire greening phase.
Harvesting and Storing Your Microgreens
Most mason jar varieties are ready to harvest between days 7 and 10, when the first set of seed leaves (cotyledons) are fully open and green. Radish moves fast and can be ready as early as day 6. Alfalfa is typically at its best around day 8-9.
Use clean scissors to cut just above the root mass. Rinse the harvested greens in cold water and spin or pat them dry before eating. Wet greens stored in the refrigerator will deteriorate much faster than dry ones.
Store harvested microgreens in a sealed container lined with a dry paper towel. They'll keep for 4-6 days in the refrigerator. Broccoli microgreens tend to hold up the longest; alfalfa is more delicate and is best eaten within 2-3 days of harvest.
One thing worth knowing: you generally cannot re-harvest mason jar microgreens the way you might regrow green onions. Once you cut them, the growth cycle is done. Start a new jar immediately after harvesting if you want a continuous supply — many growers keep 2-3 jars going on a staggered schedule so there's always something ready.
Conclusion
Growing microgreens in mason jars offers an accessible, affordable way to produce fresh, nutritious greens year-round in minimal space. With just a few basic supplies and 10-15 minutes of daily care, you can enjoy homegrown microgreens in less than two weeks. Start with one or two jars, master the basic technique, then expand your operation as your confidence grows. The satisfaction of harvesting your own microgreens, combined with their superior flavor and nutrition compared to store-bought options, makes this simple growing method incredibly rewarding.