Table of Contents
What are Microgreens?
Microgreens are small vegetable greens (or baby plants) used as nutrition supplements, flavor enhancers, or as a garnish. They consist of roots, a central stem, cotyledon leaves (or embryonic leaves), and the first pair of leaves and range in size between 2.5 to 7.6 cm (1-3 inches). Greens growing taller than 3.8cm are also called petite greens. Microgreens take between 1-3 weeks from seedling to harvest.
Growers first started cultivating a handful of microgreens in the 1980s. Nowadays, there are over 100 different microgreens! Microgreens pack a lot more nutrients, vitamins, and carotenoids compared to their mature plant counterparts. They are also super flavorful. You can use your microgreens as food garnish, in salads, on sandwiches, in soups, or in your smoothie. Harvest your microgreens just before serving to maximize nutrient count.
Different types of microgreens
Amaranthaceae family: Includes amaranth, beets, chard, quinoa, and spinach.
Amaryllidaceae family: Includes chives, garlic, leeks, and onions.
Apiaceae family: Includes carrot, celery, dill, and fennel.
Asteraceae family: Includes chicory, endive, lettuce, and radicchio.
Brassicaceae family: Includes arugula, broccoli, cabbage, cauliflower, radish, and watercress.
Cucurbitaceae family: Includes cucumbers, melons, and squashes.
Lamiaceae family: Includes most common herbs like mint, basil, rosemary, sage, and oregano.
Poaceae family: Includes grasses and cereals like barley, corn, rice, oats, and wheatgrass. As well as legumes including beans, chickpeas, and lentils
What do you need?
Microgreens are extremely quick and easy to grow. To grow your own microgreens you will need the following:
Use certified untreated seeds, you don’t want seeds that have been treated with pesticides and fungicides. These chemical substances are harmful to your health, as well as cause air and water pollution. Microgreen seeds need to be stored in a cool 4-10ºC (40-50ºF), dry place. Keep your seeds out of direct sunlight in a clean and sealed container. Buying higher-quality seeds will ensure that your seeds can be kept in storage longer and still germinate. However, storing your seeds for longer than a year may cut their germination rates by at least 50%.
You can use any type of tray or container. Add holes for drainage. To create a warm, humid environment within the trays, you may want to cover them with a (plastic) lid or plastic bag with holes for airflow.
Microgreens can be grown in soil, hemp, coco coir, or compost. If you plant to sell your microgreens, you may want to choose a soilless grow medium.
Grow Rack or Shelf
It is easiest to grow your microgreens in trays on a shelf or grow rack, for optimal use of space.
To write down the type of microgreen, date of planting, and other important details.
Plants need at least 6 hours of light per day. Use high-quality LED lights for your microgreens. When growing on a grow rack or shelf, your lights will hang very close to your plants. LEDs do not generate a lot of heat and won’t burn your plants or cause other problems. Look for a slim design, such as Horticraft Holland’s very own Fractal or Diode series.
How to grow microgreens
Some microgreen seeds need to be pre-soaked in water for 12-24 hours before they can be planted in soil. Pre-soaking softens the shell of the seeds and helps to jumpstart germination. Very large thick seeds should be soaked between 6 and 24 hours, while any grass or grain seeds should be pre-soaked for only 1 or 2 hours. You should not pre-soak seeds that become mucilaginous (meaning they’ll turn into a gooey substance) when they come in contact with water. Soaking your seeds with some 3% H202 (hydrogen peroxide) for 5 minutes can help prevent seed-borne diseases.
Use PH balanced water to soak. Water molecules contain 2 Hydrogen (H) and 1 Oxygen (O) molecules. The PH value determines the water molecule’s willingness to gain or lose one of its H molecules (ranging on a scale from 0 to 14). Germination happens at a PH level just below 6 when water is slightly acidic and can disrupt any germination inhibitors that are in the seed coating. Furthermore, this PH value helps plants absorb nutrients from the soil more easily. Adding a few tablespoons of lemon juice to PH neutral water (a value of 7) will make it drop just below the desired 6.0 PH value.
Blackout Period & Stacking
During the blackout period a grower puts a dark plastic sheet or another tray upside down on top of the tray used for growing, creating a so-called “blackout dome”. This ensures total darkness during the germination period, but is also beneficial for optimal growth. The blackout period depends on the type of microgreens, however you may want to check your microgreens after 48 hours to see how well they have germinated.
Another popular method is called “tray stacking”, in which growing trays will be stacked on top of each other. Not only will this method save up space, the weight it puts on the soil and the seeds has some advantages. The extra weight on the seed causes geotropism, a response that forces the roots downward. Furthermore, microgreen seeds grow relatively close together, making the soil come loose resulting in a dirty and messy harvest. Adding the extra weight keeps the soil compact, thus reducing the soil being thrown everywhere. The seeds will also be in constant contact with the moist growth medium, making absorbing water and nutrients easier and the added weight results in stronger and better-rooted plants.
Once the seeds have been pre-soaked, you may put them in a clean tray. Fill your containers with 1-2cm (1 inch) of moist soil or another growing medium and spread the seeds over the soil. Press lightly and cover with another 0.5cm (½ inch) of soil. Do not plant your seeds too densely, as this may cause your microgreens to be unable to breathe and prevents efficient drainage. An overgrown tray will lack proper air circulation, resulting in mold growth. It is best to plant around 2-3 small or medium-sized seeds per square centimeter and less for larger seeds.
Stack your trays to add extra weight or keep them in a blackout dome, depending on the type of microgreen you grow. Once your seeds cross the topsoil and push against the stacking tray you can start growing them under a grow light. Sometimes your plants may look white or yellow. This is not a problem, they will usually turn green once they start growing under a light source.
Use a spray bottle to water your microgreens. Lightly spray (or mist) water over the soil to prevent overwatering. Always keep the soil moist, but not too wet.
Check out our comprehensive microgreens cheat sheet below for information regarding specific types of microgreens:
Once the first two leaves emerge on your plants, they are ready for harvest. For most microgreens this is once they are 2.5 to 7.6 cm (1-3 inch) in size. Cut your plants off at soil level with sanitized scissors or a (clean) sharp knife. Make sure your workspace is clean as well. It is best to serve your microgreens directly to get the most nutrients out of them. If you want, you can store them in the fridge for a few days. Many microgreens will actually regrow and produce a second or more harvests.
Pest & Diseases
Mold and fungi thrive in an environment that lacks proper drainage, air circulation, and lightning. They can quickly overtake an entire tray and steal the nutrients from the microgreens, damaging your plants and resulting in a loss of harvest. Mold grows above the soil, directly on the plants as a spider-web like substance. It can also appear on the leaves as dark-colored spots. It has an unpleasant smell and is slimy to the touch.
Pest & Disease Prevention
- Set up proper lightning conditions. Mold prefers dark areas, 6 to 10 hours of light daily may prevent the growth of mold.
- Set up proper air circulation. Use fans or other methods of air circulation within your grow area.
- Control the humidity of your grow area. The humidity level should be between 40-60%. Add a dehumidifier to your grow area to help regulate humidity levels if necessary.
- Do not plant your microgreens too close to each other.
- Make sure your trays have drainage holes and use a grow medium that allows for good drainage. Instead of watering your plants from the top, use a bottom-watering method. This can be done by putting your trays (with drainage holes) in a bigger tray or container (without drainage holes) that acts as a water bath. The soil and any roots growing through the bottom of the tray will absorb water through the drainage holes.
- Always disinfect your equipment after every use. Use only clean scissors or knives.
- Properly disinfect trays to remove pathogens, even the trays used to put on top of growing trays (blackout dome tops). Use bleach, steam, Peracetic acid, or 3% H2O2 for sanitazing your trays.
- Disinfect and pre-soak seeds with a 3% H2O2 solution.
- Use untreated, high-quality seeds only.
- Use high-quality soil.
How to use microgreens
Microgreens can boost your dish by enhancing its flavor, making it more colorful, or adding texture. You can use microgreens on any kind of dish as a garnish or topping, such as on a pizza, in your soup, in the salad, or on top of a piece of flatbread. Toss a handful of microgreens in your smoothie to add vitamins, minerals, and fiber.