Growing Microgreens

Author: Xanthe  

Microgreens have been gaining popularity in the past few months and it is easy to see why. With only 5.1% of adult Australians consuming the recommended daily intake of fruit and vegetables we need to change how we get our fresh produce as not everyone has time or money to have access to the greens that we need to eat every day.

Thankfully microgreens have seen a rapid surge in production as it becomes more evident that these little seedlings pack a bigger nutritional punch than their fully-grown counterparts.

For example, red cabbage microgreens had 40 times more vitamin E and six times more vitamin C than mature red cabbage.

Cilantro microgreens had three times more beta-carotene than mature plants.

Four groups of vital nutrients were found including vitamin K, vitamin C, vitamin E, lutein, and beta-carotene, in 25 different commercially grown microgreens.

The reason for microgreens having so many nutrients compared to their adult counterparts is simple – they need all those nutrients to fully develop into a healthy adult plant and store all that goodness in the seed which is consumed over time as the seedling grows.

They are typically harvested within 14 days of germination and have a much stronger and usually better flavour than the usual plant. Radishes for example are much spicier than the bulb that is consumed, making them great for dishes that need a bit of extra spice.

Microgreens used to only be found in restaurants but now farmers markets and supermarkets should have some in the fresh produce section. They are usually sold to the consumer in punnets like fresh berries.

Microgreens are more like baby greens in that only their stems and leaves are considered edible. However, unlike baby greens, they are much smaller in size and can be sold before being harvested. Sometimes they can still be in the flats they are grown in.

This means that the plants can be bought whole and harvested at home, keeping them alive until they are consumed, ensuring freshness. Microgreens are very simple to grow, as they can be grown in a variety of locations, including outdoors, in greenhouses and even on your windowsill.

Microgreens are easy to grow and can be a fun project for children as they can learn and be healthy at the same time. They enjoy seeing the tiny plants grow and like to decorate their plates with the brightly coloured seedlings. It is an excellent way of teaching children where food comes from.

A recent national survey, commissioned by Woolworths, found that a third of Australian children struggled to identify fruit and vegetables, and were confused about where produce came from.

The study, which surveyed 1601 Australian children aged between six and 17 years, revealed 92% did not know bananas grew on plants.

Getting children involved in simple agriculture will help bridge the gap between paddock to plate and hopefully reduce national obesity levels which are skyrocketing, in children and adults.

Depending on where you live there will be a range of different sized trays to grow your microgreens in. Australian trays are a different size than the American standard which is usually referred to as a 10x20 or rather 10” x 20” flat.

The standard Australian size is 350mm x 295mm x 50mm which is much more solid in construction and not as flimsy as the US kind.

How to grow Microgreens

What You will need:

  • Growing Tray
  • Growing media
  • Heat Mat (optional)
  • Light Source
  • Seeds
  • Nutrient/Fertiliser (Optional)

Seeds are best kept in the fridge in the veggie crisper, protected from moisture. Keep them there until you are ready to use them.

Find a good location for your seed trays, this could be a shed, grow tent, bench or anywhere you get good light and sheltered from strong winds.

A light source would ideally be either sunlight or a horticultural light but that isn’t always an option which means you can use a desk lamp or household light if you can’t place your tray outside or on a windowsill. The plants will still grow but won’t be as healthy or grow as fast.

You can get a decent grow light from hydroponic stores for under $200 which will provide your seedlings with all they need to get started. LED’s will get cheaper the more the technology matures, and they produce minimal heat and consume not much electricity at all compared to a lamp in your home or high-pressure sodium.

Fill your tray with growing media of your choice, this could be a range of things but the most common would be soil, sand, potting mix, coconut husks, peat moss, vermiculite or perlite. Growing media is a personal preference, and each has advantages and disadvantages. One thing to consider is cheap coco coir media has come from a 3rd world country and has been exposed to salt water in the manufacturing process, meaning salt will still be present when you try to grow seeds in it.

Always check where the coco has come from before buying. Good quality coco is processed in countries like Holland and has been washed in pure water until the salt is gone, it then has calcium and magnesium added to make up for the potential deficiencies that may arise as the coco will absorb the calcium and magnesium as it breaks down. It will eventually release it like mulch does and will be an excellent compost for your garden or more microgreens! Canna, Reiziger and Hy-Gen are some brands that have been through the washing process.

In my example I used Canna Terra which is a mix of peat, coco and perlite as it has excellent drainage and is the closest to what the seeds would naturally germinate in (depending on species) but use whatever you feel comfortable with.

Spread the media evenly, about ¾ deep in the tray, my tray is 5cm deep, so I’ll leave approximately 1cm of the tray exposed. The actual planting process will vary, some people like to soak their seeds and plant them on cotton balls or paper towels soaked in water. I prefer to put my seeds straight into the media from the fridge.

Soaking is a good way to see which seeds will germinate and which will not – floating seeds are infertile, throw them out as they will not sprout. Soaking will make it harder to spread evenly as well which is important for having an evenly planted tray.

Cover the seeds with a thin layer of soil, a good rule of thumb to follow is the size of the seed deep, so sunflower seeds would need to be deeper than radish seeds as they are much larger in size.

Mist the seeds with a spray bottle, being careful not to blast the tiny seeds out of the soil, wet them not soak them!

You can use a heat mat if you like to promote germination and trick the seeds into thinking the soil is warming up meaning change of seasons. This is fine if you only have a small number of trays but if you are looking to start a business growing micro greens then this will get expensive quickly as a heat mat suited to the 350mm x 295mm tray is $40 plus a thermostat will be another $40 so $80 per tray.

If you keep your seeds in the fridge then this will trick the seeds enough that you don’t need a heat mat (provided the ambient temperature is above your fridge temp).

Mist your seeds when the tray starts getting light, if it is heavy then you do not need to water the media as it is still filled with water.

Seeds will start to germinate in a few days or even in a few hours depending on the seed, the environment and how favourable the conditions are for it. I have had corn and peas come up the very next day after planting.

You can leave the growing process here and just water the sprouts until they are ready to harvest, or you can really get involved and make it a science project. Hydroponic nutrient comes in all different shapes and sizes as well as formulas, but any base nutrient will give your plants a good start. The biggest problem with hydroponic nutrients are you can run the risk of burning your tiny plants with nutrient if it too strong. Some will also argue the seeds have all the nutrient you need to grow microgreens and that is true if you are just growing them for fun or for a light salad.

The nutrients I used are organic and has 90 different elements in the liquid, making it a good basis for growing your own superfoods. The key to not burning the seedlings is reducing the feeding strength, usually halving or even quartering it from what you would give an adult plant.

Microgreens can be grown in hydroponic systems and have crops ready for harvest within 5 days from germination versus the usual 7-14 days. Fertilizers that are slow release will burn even mature roots so do not use pelletized manures or fertilizers.

Commonly available feeding products like Seasol or Thrive do not have the same level of nutrients as a dedicated hydroponic nutrient has and is best left to the garden. Single part nutrients are great for people just starting out or on a strict budget but if you have a choice then a 2 or 3-part nutrient will always be better. 2-part nutrients need to be mixed correctly to ensure the best results, it is best to add part A to your reservoir or watering can with water, give it a good stir and then add part B and stir again.

The nutrient will have a buffer in it to adjust pH to the optimum levels but if your water is especially bad then you may need to add pH UP or Down. Nutrient lock-outs occur at certain levels, depending on what element it is. It is best to keep it at least 5.8 – 6.2 but depends on the plant. Some carnivorous plants like a pH of 2-5!



Comments (1)


By: on 27 March 2020
Hey hydro centre, what organic nutrients did you use that you mentioned in this article? are they available for purchase? thanks

Hydrocentre Hydroponics Response
Hello - Grow research all-purpose nutrients are a great natural nutrient made by brewing (like a beer) organics and natural minerals.

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