How To Grow Onion Microgreens

<a href=''>Jon Smith</a>Jon Smith
February 4, 2022

There are many different types of onions available, including bunching onions, green onions, red onions, sweet onions, cooking onions, etc. One type of onion that many people don't know about is onion microgreens. Yes! You can grow delicious, nutritious onion microgreens.

Onion microgreens are the perfect choice for new microgreen gardeners as well as those who have been growing microgreens for quite some time. Onion microgreens are quite tasty and very easy to grow, requiring very little maintenance. It takes between 12 to 21 days for onion microgreens to be ready to harvest.

Onion microgreens are loaded with nutrients. Eating these microgreens will provide you with vitamin A, C, E, and B vitamins. Additionally, you will receive calcium, iron, magnesium, phosphorus, potassium, and zinc. Finally, onion microgreens provide you with essential amino acids that your body needs for optimal health.

Onion microgreens are savory microgreens. The flavor is that of strong onion with undertones of garlic. Onion microgreens can be used just like you would use green onions or chives. Let's take a look at how to grow, harvest, and store onion microgreens.

Onion Microgreen Profile

The following table will provide you with an overview of onion microgreens. This easy-to-read table provides you with the growing information you need to get started.

Flavor Onion microgreens have a savory flavor with an onion taste and garlic undertones.  
Pre-Soak (Yes/No)  No – Onion microgreen seeds do not need to be soaked.
Color  Onion microgreens have a light green grass-like appearance.
Germination Time  Onion microgreens have a germination time of 1 to 2 days.
Harvest Time  The harvest time for onion microgreens ranges from 14 to 21 days.
Green Thumb Level (1-5)  2 – Onion microgreens are easy to grow; however, it takes 2 to 3 weeks to be able to harvest your onion microgreens.

Frequently Asked Questions

Whether you have been growing microgreens for quite some time or you are new to growing microgreens, you probably have some questions. Here are the most frequently asked questions and answer people have about onion microgreens.

Do Onion Microgreens Regrow After Harvesting?

Yes! Unlike other microgreens, onion microgreens will regrow because they grow from the root of the plant. You must keep about half an inch of growth above the growing medium surface for the microgreens to continue to grow.

How Fast Do Onion Microgreens Grow?

Onion microgreens are ready for harvest within two to three weeks; therefore, they are one of the slower growing microgreens. However, this should not prevent you from growing these awesome microgreens.

How Should I Eat Onion Microgreens?

Onion microgreens can be enjoyed in the same way that green onions and chives can be enjoyed. You can add them to your favorite microgreen salad, add them to a sandwich, or add them to your favorite soup or other cooked meal.

What Health Benefits do Onion Microgreens Offer?

Onion microgreens are chockfull of nutrients. These vitamins and minerals have been shown to reduce blood pressure readings, assist in weight loss efforts, prevent anemia, and lower cholesterol levels.

Equipment Needed to Grow Onion Microgreens

Growing onion microgreens is not difficult when you have the right equipment and know the best growing techniques. We recommend following the technique listed below. When followed, it will help ensure a large harvest of onion microgreens.

Starter Kits

A Deluxe Microgreen Starter Kit from True Leaf Market provides you with the equipment that you need to grow microgreens. A starter microgreen kit includes a set of growing trays, a misting bottle, a sample of growing medium, and a few seed varieties to get you started. In addition to these items, we recommend purchasing the optional equipment listed below as it will help improve the growth and harvest rates of microgreens.

Specific Equipment Needed for Onion Microgreens

Some people prefer purchasing individual pieces of equipment. One advantage to this is you only have to purchase the items that you need. In addition to this, you can purchase the equipment over time, which is great for those who are on a budget. You will need the following equipment to grow onion microgreens and other microgreens.

Onion Microgreen Growing Medium

One of the most common questions we get asked is which growing medium should be used for microgreens. We recommend using a soilless growing medium like coconut coir as it reduces the risk of soilborne diseases.

Coconut Coir

Coconut coir is a renewable resource that is created by grinding up the husks of coconuts. This growing medium has the ability to hold water and support the delicate root structure of microgreens without increasing the risk of disease.

MOTHER EARTH Coco Plus Perlite Mix - For Indoor and Outdoor Container Gardens, Provides Strong Aeration & Drainage, 70% Coconut Coir, Resists Compaction, 50 Liter
  • Mother Earth Coco + Perlite is a great alternative to potting soil as it enables gardeners to aggressively feed and not worry about over-watering
  • Use Mother Earth Coco + Perlite with indoor and outdoor container gardens
  • Achieve better aeration and drainage with a mix that incorporates 70% of the finest coconut coir and 30% perlite
  • Plant directly in Mother Earth Coco + Perlite
  • Coconut coir resists compaction and last longer in a container (vs traditional growing media)

Seed Starting Mix

Seed starting mix is a soilless growing medium that is fine grained, making it easier for the delicate roots of microgreens to grow. Seed starting mix contains nutrients to help young plants thrive. Because microgreen seeds contain everything the young plants need to grow, these extra nutrients are not needed.

FoxFarm Ocean Forest FX14000 -1.5 Cubic Foot Organic Potting Soil
  • SIZE: 38.6 quarts of FoxFarm Ocean Forest Potting Soil for your hungry plants
  • APPLICATION: Ultimate potting soil that has everything your plants need in one bag
  • CONTENTS: Blend of earthworm castings, bat guano, sea-going fish & crab meal, forest humus, moss & more
  • PH LEVELS: Ocean Forest is pH adjusted at 6.3 to 6.8 to allow for optimum fertilizer uptake
  • BENEFITS: Encourages strong branching and a sturdy, healthy growth habit and is ideal for containerized plantings

Onion Microgreen Growing Trays

You will need a total of three growing trays for your onion microgreens. Two trays should not have drainage holes while one should have drainage holes.

Growing Tray with Drainage Holes

The growing tray with drainage holes will be used to hold your growing medium and onion microgreen seeds. This will allow you to water your microgreens from the bottom up. Any excess water will drain, thus preventing overwatering, which can increase the risk of mold and other microgreen diseases.

10 Plant Growing Trays (with Drain Holes) - 20" x 10" - Perfect Garden Seed Starter Grow Trays: for Seedlings, Indoor Gardening, Growing Microgreens, Wheatgrass & More - Soil or Hydroponic
  • Quantity 10 - Durable Plastic - WITH Drain Holes
  • Perfect for hydroponic growing and seed starting
  • Approx: 21" by 11" (top measurement). 20" by 10" bottom of tray - See product description below for precise measurments
  • Accomodates 20" x 10" Sure to Grow Hydroponic Grow Pads and Micro-Mats Perfectly
  • Reusable - Great for Greenhouse, Seedlings, wheatgrass, microgreens and more.

Growing Tray without Holes

One of the growing trays without drainage holes will be used as a blackout and humidity dome. The other will let you bottom water your plants. It will hold the water while the growing medium soaks up the water it needs.

10 Plant Growing Trays (No Drain Holes) - 20" x 10" - Perfect Garden Seed Starter Grow Trays: for Seedlings, Indoor Gardening, Growing Microgreens, Wheatgrass & More - Soil or Hydroponic
  • Quantity 10 - Durable Plastic - NO Drain Holes
  • Perfect for use as a drip tray, hydroponic growing and seed starting
  • Approx: 21" by 11" (top measurement). 20" by 10" bottom of tray - See product description below for precise measurments
  • Accomodates 20" x 10" Sure to Grow Hydroponic Grow Pads and Micro-Mats Perfectly
  • Reusable - Great for Greenhouse, Seedlings, wheatgrass, microgreens and more.

Misting Bottle

A simple misting bottle makes it super easy to water your microgreens without disturbing the delicate roots of your onion microgreen plants.

GETTON 2.0L Garden Sprayer, Hand-held Pressure Pump Sprayer Plant Mister Spray Bottle with Adjustable Nozzle and Detachable Wand for Indoor Outdoor Household Cleaning Garden Lawn Watering
  • 【Safe Pressure Valve】The garden spraying bottle equipped with a safety pressure release valve, which allows you to control the pressure of water and automatically releases the excess pressure. The pump holds a good amount of pressure while offers a place reducing fatigue while operating the equipment.
  • 【Adjustable Nozzle】The premium adjustable nozzle of this garden sprayer can be easily adjusted the intensity of the water from direct injection to fine mist spray as desired. Greater even coverage for a better performance.
  • 【Durable & Easy to Clean】The pump sprayer is manufactured from PP material for excellent durability. 2L Translucent water tank can clearly show the liquid level inside so you can add more in time. It is also convenient for cleaning.
  • 【Wide Application】This universal pressure sprayer can accommodate your daily cleaning and watering needs both indoors and outdoors . Ideal for household cleaning, watering plants and flowers, misting veggies, pet bathing, and moisturizing flowers.
  • 【Ergonomic Handle】The pump pressure sprayer comes with an ergonomic 4-finger handle that is non-slip for effortless use and convenient to be carried anywhere. A removable long wand is good to help spray more spaces or hard-to-reach places.

Onion Microgreen Light Source (Optional)

A full spectrum LED grow light will provide your onion microgreens with the light that they need to thrive. When properly placed, a grow light will ensure the even growth and development of your microgreen plants.

Barrina LED Grow Light, 144W( 6 x 24W, 800W Equivalent), 2ft T8, Full Spectrum, High Output, Linkable Design, T8 Integrated Bulb+Fixture, Plant Lights for Indoor Plants, 6-Pack
  • Full Spectrum - Barrina grow light is a great option for plants that in seedling, vegetative and flowering cycle. It provides light that plants need, especially blue and red light
  • Integrated Plant Light Chips- Compare with the lamp consisting of only "blue chips" + "red chips", integrated plant light chips have more efficiency and better color layout
  • Super Bright - Consume only 144W with 576 LEDS totally, replacing 800W general plant lights. These grow light provid a higher PPFD
  • Easy Installation - Plug and play. And could link up to 6 grow lights in a series by 48 inches connecting cords. Also, you could mount to ceiling or hang up for shelf. Saving your installation cost and time
  • Quality Assurance - 2-year unlimited warranty, easy and fast replacement is offered if any quality issue

Onion Microgreen Heating Mat (Optional)

Although a heating mat is optional, we highly recommend purchasing one for your microgreens. Heating mats ensure optimal temperatures throughout the germination period. When the growing medium is kept at the recommended temperature, germination rates will be boosted.

HYDGOOHO Waterproof Seedling Heat Mat for Seed Starting Propagation and Increase Germination Success 10 Inch x 20.75 Inch MET Safety Standard Certified
  • Makes a differeance in germination time, leafy greens in about 2 days and tomatoes 3-4 days for sprouts.
  • Try to use the seedling heat mat and heat mat thermostat to heat water in the seed container to increase humidity in your grow tent.
  • Using to keep a batch of fermenting beer wort at 72F is also available
  • Great affordable heating solution to starting plants from seed.
  • If you’re doing home gardening for your seasonings, go find this seedling heat mat sets.

Onion Microgreen Planting Rack (Optional)

A microgreen planting rack provides you with vertical storage for your microgreen trays. By utilizing the vertical area of your home, you can grow multiple trays of microgreens without sacrificing a lot of floor space in your home. Furthermore, planting racks provide the perfect way to hang grow lights and circulation fans to ensure optimal growth and development of your onion microgreens.

Storage Shelves 2100Lbs Capacity, 6-Shelf on Casters 48" L×18" W×82" H Wire Shelving Unit Adjustable Layer Metal Rack Strong Steel for Restaurant Garage Pantry Kitchen,Black
  • IMPRESSIVE STORAGE CAPACITY - With six tiers of shelving, this unit boasts an enormous amount of space and shelving. It’s able to provide a great deal of additional storage without taking up too much space itself.
  • STURDY AND DURABLE - Constructed from heavy-duty steel wire, this shelf is durable and resistant to dirt buildup and corrosion. Each shelf has a capacity of up to 220 lbs when properly assembled, with a maximum weight capacity of 500 lbs total.
  • ADJUSTABILITY - You can adjust the height of the storage shelves in one-inch increments, creating a customized unit best suited for your specific storage needs.
  • MULTIFUNCTIONALITY - This metal shelving unit can be used virtually anywhere, in the kitchen, the bathroom, the garage, outdoor shed, and more. It’s perfect for storing tools, clothes, books, and whatever else is taking up space in your home or office. Equipped with wheels, you can transport this unit smoothly and efficiently room to room.
  • FAST, EASY ASSEMBLY: The shelving unit comes packaged ready to assemble, and doesn’t require any tools for installation. In just 15 minutes, your unit can be installed and ready to save space.

Onion Microgreen Circulation Fans (Optional)

Although circulation fans are optional pieces of equipment, we recommend every microgreen gardener purchase and use them. Microgreen circulation fans increase the airflow around plants which helps reduce the risk of mold, mildew, and other diseases that can damage your microgreens.

Active Air HORF6 6-Inch Clip-On 360-Degree 5W Brushless Motor Hydroponic Grow Fan with Spring-Loaded Plastic Clip for Gardens, Black, 2 Pack
  • LONG LASTING: Fan features a 5W brushless motor that lasts longer and can be hooked up to fan speed controllers; Features a smooth and quiet operation (2 Pack)
  • CLIP-ON DESIGN: Clip-on portable fan is convenient and effective for small spaces; Can be used to help grow healthy plants or for cooling, in your garden, flood tables for airflow under foliage, small spaces, or on your office desk with a spring-loaded plastic clip that won't mar surfaces
  • AIR-FLOW: With the 6-inch adjustable-angle head that rotates 360 degrees you can direct airflow where you need it and it can also be wall-mounted to free up space
  • DURABLE: The cooling fan features 3 durable plastic blades and the easily-removable safety grills make cleaning a breeze; The motor outlasts traditional fans that use oil to lubricate rotation
  • SPECIFICATIONS: The product has a 6-foot power cord and is powered by DC 5V/5W making it energy efficient; Weight: 1 pound; Dimensions of (L x W x H): 6 x 8 x 8 inches; Quantity: 2

Onion Microgreen Seed Options

There are a number of onion microgreen seed options available. Each type of onion microgreen has a slightly different growth pattern and taste. Here are the top onion microgreen seeds available at True Leaf Market.

Crystal White Wax Onion Microgreen Seeds – Mountain Valley Seed Company's Crystal White Wax onion microgreens are an heirloom, non-GMO onion microgreen that is ready for harvest between 14 and 21 days after planting. Crystal White Wax Onion is one of the sweetest onions on the market, making it a great microgreen to use in your microgreen salads.

Utah Yellow Sweet Spanish Onion Microgreen Seeds – Mountain Valley Seed Company's Utah Yellow Sweet Spanish Onion microgreen seeds are non-GMO, heirloom seeds that produce a consistently flavorful and nutritious onion microgreen. Utah Yellow Sweet Spanish onions are mild flavored and delicious on sandwiches.

Tokyo Long White Bunching Onion Microgreen Seeds  - Mountain Valley Seed Company's Tokyo Long White Bunching Onion is a non-GMO heirloom onion. This type of onion has a long, slender, grass-like appearance. These microgreens have a delicious, yet delicate onion flavor.

Southport Red Globe Onion Microgreen Seeds – Southport Red Globe onion microgreens by Mountain Valley Seed Company are non-GMO, heirloom seeds. This red onion microgreen has a crisp, onion flavor that works great in soups, stews, and sandwiches.

White Sweet Spanish Onion Microgreen Seeds - White Sweet Spanish onion microgreen seeds are non-GMO, heirloom seeds offered by Mountain Valley Seed Company. These sweet onion microgreens are extremely mild with a delicate sweet flavor that is delicious when combined with other microgreens like cabbage, peas, or arugula.

Organic Evergreen Bunching Onion Microgreen Seeds – Heirloom, non-GMO, USDA certified organic Evergreen Bunching onion microgreens by Mountain Valley Seed Company provide a delicious spring onion flavor that is perfect on sandwiches or placed in your favorite soup or salad.

Step by Step Growing Guide for Onion Microgreens

Growing onion microgreens is not difficult when our easy to follow, step by step growing instructions are followed. We thoroughly explain each step of growing, harvesting, and storing onion microgreens. If you are ready to grow a bountiful crop of onion microgreens that are full of flavor and nutrition, gather your supplies.

Step 1 Prepare Your Onion Microgreens Growing Trays

Once you have gathered your onion microgreen growing supplies, it is time to prepare your trays for planting. Fill the microgreen growing tray with drainage holes with your preferred growing medium.

Press the growing medium down with your hands or a piece of cardboard, ensuring the growing medium is even and level across the entire tray. The top of your growing medium should be slightly below the top of the tray.

Next, you need to thoroughly moisten your growing medium. You can do this by either soaking your growing tray in water, allowing the growing medium to absorb the moisture, or you can mist the entire surface of the growing medium using your water mister. Once your growing medium is moistened, you will need to place the tray with drainage holes inside a tray with no drainage holes.

How to Soak Your Growing Medium in Water

If you choose to soak your growing medium in water, fill your sink or tub with an inch or so of water. Place the growing tray in the sink or tub, ensuring the water does not go over the top of the tray. Allow the tray to sit in the water for at least 30 minutes. The growing medium will slow wick the water up.

How to Moisten Your Growing Medium Using Your Misting Bottle

If you choose to use your misting bottle, spray the entire surface of the growing medium until water begins to puddle on the surface. Allow the growing medium to absorb the water for 15 to 20 minutes. Then, spray the surface again. Continue spraying and allowing the growing medium to absorb the water 4 more times to ensure the growing medium is sufficiently moist.

Step 2 Plant Your Onion Microgreen Seeds

Once you have prepared the soil in your growing trays, it is time to sow your onion microgreen seeds. Onion microgreen seeds are extremely small. To ensure even disbursement across the entire surface of the growing medium, we recommend using a spice shaker like this one.

You will need approximately one half of an ounce of onion microgreen seeds for each 10 inch by 20 inch tray. Sprinkle the seeds evenly across the entire surface of your growing medium.

Once you have sown your seeds, you will need to cover them with a thin layer of growing medium. Grab a handful or two of your growing medium and sprinkle across the freshly planted seeds. Press down gently with your hands. Then, mist the entire surface of the soil with three to four sprays of water.

Step 3 Understand the Onion Microgreens Germination Process

When you plant a seed in the ground, you cover it with soil and water it. We mimic this by inverting a growing tray and placing it atop the soil. This will prevent any light from reaching the microgreen seeds.

Next, you will place a heavy book, weight, or stone atop the inverted tray. Don’t worry, the weight will not hurt your microgreens. In fact, it helps strengthen the roots, which produces healthier onion microgreens.

Once you have gotten your trays ready for the germination process, place your microgreen tray on top of your heating mat. Onions germinate best at 75 degrees Fahrenheit. Set to the desired temperature. Your onion microgreens should germinate within a day or two.

You will need to check the moisture level of the growing medium each day to ensure it remains slightly damp. If the soil feels too dry, lightly mist the top of the surface and then, replace the inverted tray. Once approximately 90 percent of your onion microgreens have germinated, it is time to remove the blackout tray and place your microgreens under your LED grow lights.

Step 4 Place Your Microgreens Under Grow Lights

Turn off the heating mat and turn on your grow lights. Onion microgreens need about 16 hours of light and 8 hours of total darkness. Thanks to the capabilities of grow lights, you can control the amount of light your microgreens receive.

Grow lights should be placed about 8 to 12 inches from the surface of the growing medium. Your microgreen planter's rack provides the perfect way to hang your grow lights. Finally, a simple timer allows you to set when your grow lights will turn on and when they will turn off, taking the guesswork out of your microgreen gardener.

You will need to check the moisture level of your growing medium each day. If your soil is allowed to dry out, it can cause your microgreens to wilt and even diet. Conversely, overwatering can cause mold to develop, which can kill your onion microgreens.

If your soil becomes dry, pour 1 cup of water into the bottom tray and allow the growing medium to absorb the moisture for about an hour. If any moisture remains in the bottom tray, pour it out.

Step 5 Turn on Your Circulation Fans

Circulation fans are used to increase the airflow around your microgreens. Microgreens are planted very close together, which increases the risk of soilborne diseases like mold and powdery mildew. The circulation fans reduce the risk of soilborne illnesses.

Place the circulation fans on the sides of your planter's rack. When you are placing your circulation fans, make sure that the air only blows across the top of the onion microgreens. If the air blows across the surface of your growing medium, it will dry out too quickly.

Step 6 Know When to Harvest Onion Microgreens

Your onion microgreens will be ready for harvest in two to three weeks. Unlike other microgreens that are harvested when the first set of leaves begin to appear, onion microgreens are more grass like and do not develop leaves. Instead, they are ready to harvest when they reach approximately 4 inches tall.

When your microgreens get tall enough to harvest, withhold watering for 12 hours. This will ensure your harvested microgreens remain crisp and fresh for a longer period of time.

Cut the microgreens about 1/2 of an inch from the surface of your growing medium. Because onions grow from the bottom up, you can continue to harvest your onion microgreens by allowing them to regrow by following the growing instructions listed above.

Harvesting Onion Microgreens

You will need a sharp pair of scissors or a sharp knife and a couple of clean, dry paper towels. Make sure that absolutely no moisture touches your microgreens during the harvest process.

Gently grasp the onion microgreens in one hand and then quickly cut the microgreens about 1/2 of an inch from the top of the growing medium, placing them on the paper towels as you cut them.

Work as quickly as possible as the more the microgreens are exposed to air, the shorter their life expectancy will be. Also, only harvest one tray at a time to reduce air exposure.

If you will be eating your onion microgreens immediately, fill a bowl with cool, not cold water. Place the microgreens in the water and quickly swirl to remove any dirt. Then, place the onion microgreens in a single layer on the paper towels to dry.

If you plan to store your onion microgreens, lay them on a single layer of paper towels and then proceed to the next step.

Storing Onion Microgreens

In order to maximize the storage time of your onion microgreens, you will need to place them in an airtight storage bag or an airtight container. Grab a clean paper towel and loosely wrap your onion microgreen in the paper towel.

Then, place the wrapped onion microgreens in a storage container. Your microgreens should be stored in the crisper area of your refrigerator. To maximize your storage time, your refrigerator should be maintained to 35 to 45 degrees Fahrenheit.

When microgreens are properly harvested, packed, and stored, they will remain fresh for about 10 to 12 days, which gives you plenty of time to enjoy your delicious onion microgreens.

When you are ready to eat your onion microgreens, rinse them in cool water. Then, place them on a paper towel to dry before eating.

Final Thoughts

Onion microgreens can be used and enjoyed much like chives or green onions. You can use them as a garnish, add them to a microgreen salad, sandwich, or soup. They are also a wonderful topping for a baked potato.

Onion microgreens are easy to grow. Simply follow our step by step growing instructions for onion microgreens. Within a couple of weeks, you will be enjoying nutritious, delicious fresh onion microgreens.

As an Amazon Associate I earn from qualifying purchases. Assume all links are paid links.
How To Grow Onion Microgreens
Primary Item (H2)Sub Item 1 (H3)Sub Item 2 (H4)
Sub Item 3 (H5)
Sub Item 4 (H6)
About The Author
I have been growing microgreens for myself and others for quite some time now and I absolutely love the process.

Even more I love spreading awareness of an amazing crop that has so many nutritional benefits for our bodies which improve our overall health and wellbeing.

Jon Smith

Copyright 2021 All Rights Reserved!

As an Amazon Associate I earn from qualifying purchases.