Is It Smart To Grow Microgreens Without Soil?

Ed Wike
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Experiment Details

Seven different microgreens were grown in each of five environments, with each environment being identical except that the microgreens were grown in soil substitute (hydrosphere), soil-less growing medium (CocoTek), or nothing (floating in water, or under a 50% shadecloth cover).

The five growing environments are:

  • Seeding in Hydrosphere, transplant to Hydrophere, CocoTek, or nothing
  • Seeding in Soil, transplant to Soil, Hydrosphere, or nothing
  • Seeding in Soil, transplant to Soil, CocoTek, or nothing
  • Seeding in Soil, transplant to Soil, nothing
  • Seeding in Soil, transplant to CocoTek, nothing

Results from the experiment show that when microgreens were seeded in a hydrosphere and then transplanted to a hydrosphere, soil substitute, or nothing, they had up to 20% more pungency (freshness) and overall health, by day 12 and up to 55% more pungency (freshness) and up to 4 times more total antioxidant activity (ORAC Value) by day 13 than when microgreens were directly seeded in soil or substrate.

Sowing Seeds

Microgreens can be grown right on top of the tray or pot where they will be planted. If you want to do this, be sure to use fabric bags that have tiny holes in them for drainage and holes or cut-outs for stakes to hold the fabric down. It's important that the seeds are evenly distributed throughout the bag and that the seeds and growing medium in the bag are in contact with the water and air, or you'll end up with anaerobic conditions that can kill seedlings.

Keep the seeds evenly moist at all times, but never soggy. It's crucial that excess water drains away from the seedlings. Moisten the bag or container with just enough water to keep it in constant contact with the growing medium and seeds, but do not soak it. Every day, gently wash away excess water with a hose and keep it regularly moistened with a watering can.

Watering

Microgreens, like all plants, need water in order to grow, and they need it often. You can use a spray bottle every so often, or you can use the bottled water dispenser a couple of times per day. If you use bottled water, make sure that you rinse the bottle before you refill it. The common perception is that larger amounts of water will leach nutrients from the soil, but with only a small amount of nutrient powder in the microgreen growing mix, this is not a concern.

Can Microgreens be Planted in Soil?

Yes, microgreens can be planted in soil, if you want to transition them into the soil as opposed to transplanting them for a harvest. The seedling bed should be lightly amended with soil, as this will help you avoid disturbing the roots, after they have been planted in the initial growing mix.

Transplanting microgreens into soil means that you will need to handle them more often. Be careful to avoid damaging the roots, because the plant needs to recover from the transplant process before it can grow. If you are just starting out growing microgreens in soil, it is a good idea to start with small batches. Practice with a few plants until you get a feel for handling them.

Thoughts on Growing Media

Growing microgreens without soil used to be against the rules. That was before soilless media entered the agricultural arena.

Accelerated soilless propagation changed the world of microgreens and organic farming forever.

There is still a lot of debate on growing microgreens in soil or growing media of any kind.

Some growers believe that growing microgreens above the ground encourages fungal and bacterial transmissions and the movement of more dirt into the growing environment.

Investigations have also found soil based systems to be a greater harbor for pathogens such as E. coli and salmonella than soilless growing environments.

This information might lead us to believe that the soils are the cause of contamination, or the soil could be an inadequate growing medium.

There are other types of risk factors that could be considered before we completely disregard using soil as growing material.

Topsoil, at least in some parts of the country, can contain high concentrations of heavy metals, industrial and military pollutants, naturally occurring carcinogens, reclaimed sewage, and nitrates.

Though it is possible to grow microgreens using organic soils the buying of these soils and compost would limit your options for ingredients.

It would be hard to get a large volume of quality organic soils, and unavailable for the majority of the growing season.

Side By Side Results

The question for those who want a garden with a low startup cost, minimal time investment, and no soil, is: do you have to grow them in soil? All you need to grow microgreens is light and water, right? You can grow them from seed with such limited resources, so why on earth would you need to use soil?

A stage was reached in the development of hydroponic growing methods when the scientists who were testing the viability of growing plants without soil started to use this method within a controlled environment. The system was set up so that it would be practical for small and medium-sized greenhouses.

The results of this approach allowed the plants to grow faster and resulted in significantly higher yields. As a result, the plants harvested at the end of the growing process had properties that were more similar to those produced from plants grown on the soil than those grown without soil.

However, there is still a big difference between plants grown with soil and those grown without it.

Although soil was previously a necessity in the process of growing plants, it is no longer a requirement. If you want to grow microgreens in a manner that is both productive and practical, whether or not you use soil is up to you.

Soil Results By Day

Filling the tubs with water and covering it with fluorescent lights results in sprouting food seedlings that are healthy and grow very quickly. The design is affordable, easy to maintain, and uses a renewable energy source.

The team found that certain nutrients from both the water and the seeds combined to make the perfect combination for sprouting. As tiny as they are, the greens are most certainly edible. The intricate light and water design sets the stage for healthy, quick growing microgreens.

Cellulose Results By Day

If you regularly source food from your own garden or even from your local farmer's market, then you are aware how fresh produce tastes so much better than store-bought items. But why? The reason is that it is so much more nutritious.

Produce from the supermarket is usually at least several weeks old by the time it reaches the store shelves. This lengthy delivery process means that the produce must be stored in cold storage rooms so it doesn't spoil. In order to keep it fresh, several things are done to the produce. It can be doused with pesticides and even synthetic waxes. Products such as waxes are not necessary and they can pose a danger to you and your family's health if you consume them. These products are for cosmetic purposes alone.

Now, ask yourself this. Would you rather eat a fruit that was sprayed several times with pesticides, or one that is free from such substances? Of course you'd choose the latter. Now, make the difference in your food even more noticeable by growing your own foods. There is a way to do this and not have to deal with pesticides, synthetic waxes, and unpleasant respiratory hazards.

You can use a hydroponic system to grow your food indoors. That way you can skip the hazards that come with produce grown in soil. Instead of soil, you can use water and nutrients to grow your food. This eliminates the exposure to the hundreds of pesticides that are contained in soil.

Vermiculite Results By Day

Microgreens are baby “ greens. The term “micro” refers to their small size, usually about two inches tall. As the name implies, microgreens are grown from very young seedlings, making them a very, very fresh vegetable. Microgreens are supposed to be packed with nutrients, vitamins, and minerals, any of which may be lacking in the diet that makes them popular in the first place!

Traditionally, microgreens are grown in soil. A seed is planted directly into the soil then allowed to grow until a few sets of leaves have emerged from the soil, then it is harvested. The resulting plant is de-seeded and the smaller leaves are harvested and sold as microgreens.

The downside of growing microgreens in soil is that they take a relatively long time to grow. A 5 day soil microgreen garden takes about a month to complete from planting to harvest.

Vermiculite is an alternative to soil for growing microgreens. Vermiculite is made from a process that turns small balls of rock into a light, porous, mineral rich material. It has been used for decades to grow plants in a variety of settings from the home greenhouse to the big commercial greenhouse. It is a simple sensory experience to grow microgreens in vermiculite compared to soil.