How to Grow Microgreens Indoors all Year Round
In the journey from seed to plate, microgreens have gained an important role in the way we grow and harvest edible greens indoors. Once considered a hippie fad, microgreens have now become mainstream and are found on plates across the world.
Growing microgreens is the practice of densely seeding greens that range in flavour and nutrient variety. The seeds are germinated using direct sunlight in a bright window or artificial grow lights, and then harvested at an immature stage of growth.
Reasons to Grow Microgreens
There are many reasons why you should consider growing microgreens:
Microgreens offer avid gardeners the ability to have organic homegrown food produced during months when outdoor growing isn’t possible.
Because microgreens are harvested before growing into a mature plant, harvest happens relatively quickly, most cases in 7-14 days.
Microgreens come in an assortment of flavour profiles, that include sweet, spicy, earthy and sharp.
Harvested homegrown microgreens can be stored in the fridge and have a much longer shelf-life than store bought ones.
Microgreens offer more nutrient density than fully grown plants which is why they’re often referred to as a “super food”.
Store bought microgreens often come in plastic making them a less than sustainable choice.
Recommended Varieties
So many options, where to start. Here are our favorite varieties to grow:
Pea shoots: incredibly versatile and tasty. Pea shoots are hardy and have a great sweet crunch. They look elegant on the plate and are the perfect introductory microgreen.
Arugula: that hit of ‘hot’ or ‘spicy’ that full grown arugula has; ideal topping for pizzas and soups.
Cilantro: although a controversial flavour, cilantro is often easy to bolt in the garden and so harvesting it as a microgreen makes for an abundance of delicate leaves.
Mustard Seeds: these easy to grow microgreens pack a punch! Add the flavour of horseradish to your favourite dish.
Brassica Seeds: (Cabbage, Kale, Broccoli): Grow these microgreens and give your smoothies a boost of flavour and nutrition.
Materials you need to grow microgreens
You will need:
Repurposed plastic clamshell or seed starting tray with drainage holes
Solid base saucer or tray
Organic microgreen seeds
Misting spray bottle
Bright light source: South-facing window, grow light or strong light source
A word of caution: while you don’t specifically need an artificial light source to grow healthy microgreens, it will definitely help. Strong direct sunlight from a South-facing window can and will work, but be mindful as the light is sparse near the Winter Equinox that you may have less success.
Growing Instructions
Fill seedling tray or repurposed container with pre-moistened potting mix; potting mix is important as it contains the right soil mix for containers. It will contain perlite, a substance that helps retain moisture in the soil. We suggest something comparable to Promix Organic Vegetable & Herb Mix.
Smooth soil to create an even surface. This will allow the seeds to lay flat and to evenly germinate. You don’t want to compact the soil, rather be sure it’s evenly distributed.
Scatter seeds on surface of soil evenly. Seeds may be touching but not overlapping. Microgreens can tolerate a dense seeding, as they’re not growing into mature plants. Gently press the seeds into the soil.
** Caveat, coconut coir is not necessary but *may* help to retain moisture and improve growing conditions. Scatter coconut coir over soil and seeds, using fingers to break up any clumps. Seed may still be visible through coir, this is not a problem.
Using a spray bottle with a misting function, mist the surface of the soil and seeds carefully so as not to disturb seeds. Mist until saturated.
Place container(s) by a sunny window or under a grow light and mist with water daily.
Seeds should germinate in 4-6 days; once germinated, if the seeds are under grow lights, keep them at a minimum distance of 2-4” as to encourage uniform growth.
Once the new green growth appears from the seeds, you will need to begin watering from the base (bottom watering). This encourages strong root development and prevents damping off. You should know when watering is needed by the weight of the tray/container. Dry soil feels lighter when lifted.
Carefully lift microgreen tray or container and place it on a saucer or other water retaining tray. Fill saucer with water. By watering from below, the seeds are encouraged to send roots downward to access water. You'll know when your microgreens have taken up water as the container will feel heavier. Don't leave excess water sitting in the tray.
Should microgreens start to grow leaning in one direction towards the light source, rotate the tray in order to have uniform growth.
Harvest generally occurs when the first set of true leaves appears on your microgreens. The first set of leaves to appear are called cotyledon and are not the “true” shape and form of the plant’s leaves. Let the microgreens continue to grow past the cotyledon stage and wait for the next set of leaves (the first set of “true” leaves) to appear.
Harvest with scissors or a sharp knife, cutting at the base of your microgreens. You may harvest your microgreens all at once or in stages. Harvest times range based on variety, consult your seed pack for a general time frame. Once harvested, microgreens do not need to be washed. Store microgreens in an airtight resealable bag or container wrapped in a damp paper towel.
Compost remaining soil and roots. Soil, coir and roots should not be used for subsequent seedings.
Wash and dry growing tray and saucer with warm water and mild soap. You’re ready to grow again!
Additional notes
Soaking larger seeds like peas in water for 24 hours before sowing encourages quicker germination, however this isn't necessary. Expect delayed germination and harvest times if your tray is placed in cooler environment. You can harvest all your microgreens at once or as needed over the course of a few days. When microgreens grow too long, they can start to change in flavour and texture. Tender microgreens taste best and are ones that are harvested before they grow too mature. Tasting your microgreens will help ensure that you harvest them when you find them tastiest. Keep notes for subsequent harvests.
This blog post is based on our Microgreens 101 Module, included as a bonus module in our A Year in the Urban Garden Master Class. The module includes additional notes, 2 recipes, more instructional photos and worksheets.
If you have any questions about A Year in the Urban Garden, feel free to contact us!
