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Can You Reuse Microgreen Soil?

reuse microgreen soil

In several years of growing these beautiful microgreens for us and other customers, we have seen the best results with changing soil each growing cycle. But, nevertheless, if you are home growing enthusiast, you can test it by yourself and you might see some spectacular results.

You can reuse the soil used for growing these crops. However, to reuse this soil for growing more than one season involves some set of steps that need to be followed. These are mandatory steps that should be followed to balance the overall soil health and good production of the crop.

After harvesting crops, people are often confused about whether to reuse the soil or not for the second batch. If you do it right, reused soil can be rewarding for your next set of crops. It can save you money and also overtime soil can gain various nutrients. It has numerous advantages and most importantly this process is eco-friendly.

How to reuse the Microgreen soil?

It is not a very difficult task to prepare the soil for its reuse. The stems and roots of the previously grown plant need to be broken down well. Composting is a method used for breaking down the roots and stems which approximately takes 11-12 days. You must leave the soil with stems and roots because they add nutrition to the soil. The soil turns dark when you leave the soil for several days to compost. When you observe the dark color in soil, it is a confirmation that this soil can be now utilized for growing crops. You can also add some fertilizers and topsoil for enriching this soil. You can follow the below 2 methods for reusing the soil:

reuse microgreen soil

Beautiful Microgreen Root System 🙂

  1. Flip the soil

This is the easiest way of reusing the soil; it saves you a lot of time. All you have to do is take the tray which contains soil and flip the tray upside down. Now you can use the backside to grow crops. Backside plants start growing on the other side roots and stem starts decaying and start adding nutrients to your soil and it will help your new seedlings to grow well. Although this technique is easy and cost-effective it gives chances for a mold to grow. So chances of yielding a good quality crop are most likely reduced. If any non-germinated seeds exist, it may increase the mold generation. That is why, we recommend the second option.

  1. Vermicompost

This is one of the best ways to compost the soil. Vermicomposting is a method where you use the worms to decay the organic waste, dead roots, food or vegetable leftovers, and bedding materials. The worm’s job is to breakdown the wastes then replacing the soil with the organic matter with higher levels of nutrition. One can purchase worms online or from the market at the lowest prices from a garden supplier. This organic matter is nothing but vermicast or worm manure. It is an efficient way to treat the soil and transform the used soil to nutrition-rich soil. This can give you healthy and good yields. Although this process takes a quite long time, it is worth waiting for great quality soil for growing your microgreens.

If you have enough time then it is recommended for you to try the vermicomposting technique.

reuse microgreen soil


Things to remember while composting              

Composting can be done either outside or inside. Depending upon the quantity of the soil you can choose either large or small bins for composting. If the soil has gone through proper composting for a long time, then the soil will be pasteurized. You can say pasteurization is similar to the sterilization of soil. Along with that, there are a lot of other processes that happen. Over a long period at warm temperature conditions, microorganisms start decomposing the waste inside the bin. Maintaining the right temperature plays an important role over here, at incorrect temperature microorganisms will fail in killing the fungus and other harmful bacteria. For killing the pathogens required temperature is 55degree Celsius maintained for 3days. If you want you can stir the soil every 3 days. This can be continued for 15 days.

Can you reuse grow mats?

When compared to the soil medium, growing mats are easy and convenient to use, but all these mats are not very well reusable. Since most of the growing pads are fibrous in texture. For example coconut coir, hemp fiber, it is not a great idea to reuse them for growing the next batch of the crop. You can choose to compost rather than reusing for growing these plants. It is ideally not to reuse growing mats as they do not provide the reuse benefits when it comes to large scale projects because that involves a lot of effort in reconditioning. No doubt these mats are rich in a nutrient that elevates microbial growth. These microbes also become responsible for causing the problems in reused mats.

There are ways to make these substrate mats reusable. You have to bake the mats for a shorter duration then soak them in diluted hydrogen peroxide. Then it is required to wash them in some of the nutrient solutions. It is a very time and effort consuming process to follow. The best way is to reuse the mats by composting them or mix them in our garden soil. Reusing the mats can waste your time and efforts. Soil medium can be highly beneficial as it is reusable and cost-efficient.

reuse microgreen soil

Garden Cress Grown On Coco Coir

What to do with the soil after harvesting?

Either you can reuse the soil for growing microgreens or you can choose to use it in the garden by mixing it with garden soil. For reusing this soil you need to add compost and add some fresh soil to it. You can make the compost on your own to mix with the soil or buy it from the store. It is not a good idea to throw away the soil after harvesting instead reuse it.

How do you sterilize the soil for microgreens?

Sterilizing the soil is one of the advanced techniques adapted for treating the reused soil. You can sterilize the soil by putting the soil into a metal tray and placing that metal tray in the oven for the period of 2 or 2.5 hours at 320 degrees Fahrenheit. For the proper sterilization of soil, you need to remove leftover roots and stems in the soil. In case if any organic matter remains in the soil during sterilization it starts creating some weird smells and smoke. This is normal and just confirming that soil is being sterilized.

You can also sterilize soil on your own or choose to buy from the market as it is readily available. If your requirement is for small then you can sterilize on your own as it can save you money from buying. If you have a large-scale project then you might need to think of a larger setup for sterilization.

Can you reuse coconut coir for microgreens?

The answer is yes, you can reuse the coco coir medium for growing microgreens. But before reusing it you’ve to get rid of the dead roots present from the previous crop. You can also transform these dead roots into nutrients that are required in the soil. If you forget to do any of these processes then you’ll have a tough time while growing them. Coco coir is an eco-friendly, cheap, and highly rich in nutrient growing medium for them. So it is always a brilliant idea to choose coco coir medium. Reusing coco coir medium can save you money, labor, and time but it comes at a cost of some effort.

How to break dead roots in coconut coir medium?

Roots grow densely in coco coir medium so if you don’t break down roots then-new crops will not be able to grow their roots. Breaking down the dead roots needs an enzyme called sensizym. Sensizym is an advanced nutrient hydroponic enzyme that comes in 2 product formulas i.e., the original version and OIM-certified formula. Both of these formulas aid in breaking down the dead roots and turn them into a source of food for the next batch of crops. It is a concentrated formula of enzymes which is to promote helpful bacteria in the rhizosphere to elevate the growth of a crop by digesting the dead material and transforming them into biologically available nutrients. This formula is well-suited with both pH balanced and non pH balanced base nutrients. In this process the enzymes present in sensizym helps in reconditioning the coconut coir, which in turn develops a healthy environment for future crops.

These enzymes transform dead root substance to sugars, once this transformation is completed then useful microorganisms consume these sugars for their energy. Subsequently, they start producing more and more enzymes that will keep continuing this cycle which will lead to cleaning up the roots. It is entirely safe to reuse retreated coco coir, it is sturdy as well which makes it beneficial to reuse it 2-3 times without any fear.

reuse microgreen soil

Root Structure Of Red Cabbage.

Why is reconditioning needed for coco coir?

Once you finish harvesting microgreens or any crop then you must consider reconditioning coconut coir.

If you don’t do it before using it for the next batch then the crop will face a lot of problems and at that stage, it is hard to fix it. One of the major issues faced is the toxicity of the salt. Steps to follow for reconditioning are listed below:

  • Physically break roots and remove them from coco coir.
  • To flush the excess salt present in the medium, you need to wash the coco coir with distilled water thoroughly. If you don’t remove salts then it halts the traverse of nutrients to plants which leads to a lockout of nutrients in the crop. This condition can look like a deficiency of nutrients. It will cause wilt and discoloration in the crop eventually killing the entire plant.
  • To get rid of the previous crop remaining roots now you have to soak the coco coir in sensizym solution.
  • In the previous crop if you haven’t made use of any useful bacteria then add them at this step. If used then those bacteria will still exist and will benefit your next yield.
  • Now you’ve successfully reconditioned it and it is ready to be used for growing microgreens.

As this medium is reused, it starts losing its sturdiness and lignin structure. Hence this medium can be reused up to 3 times, after that it starts breaking down into pieces. At this stage, it will not be able to hold the roots of the plant. Some people also choose to mix fresh coco coir to extend their durability. Once this medium starts breaking it loses its capacity to hold the optimal moisture levels.

Problems faced while reusing Microgreen soil

You’ll run into a lot of issues when you haven’t followed the steps properly. These issues will hinder the growth of the crop. One such issue is mold. It will lead to a series of problems like reducing the quality of the soil, which in turn decreases the production. It can also kill the crop to a larger extent.


When the soil is not composted properly it leads to mold. Mold appears like a spider web. You have bigger chances of getting confused between the root hairs of plants and mold. Roots have a fuzzy texture whereas molds are slimy when you touch them. Eventually, it can reduce the quality of the soil and temperature promotes the production of the mold, too much saturation of the water. Since the mold can cause microbial activity in the soil, it will affect the microgreens growth. Poor quality of the soil can reduce production levels.

Make sure that the soil is properly composted and verified before growing the crop.


Reusing the soil can be worth rewarding, saves a lot of money, and is eco-friendly. If you maintain your soil healthy, one can grow 2-3 seasons of the crop by reusing the same soil and also by mixing fresh soil with it. You can reuse the mediums like coco coir if you recondition them well. If you are growing on a large scale then follow techniques like sterilization of soil, reconditioning of the medium, avoid mold accumulation, use the right enzymes, and correctly reuse the growing mats. We understand that when you are growing on a larger scale, then having the same quality soil is essential. That is why a lot of growers, including us, are buying already prepared soil and with this we avoid growing problems. But to make the world a healthier place, start growing microgreens at home with eco-friendly techniques and enjoy the richness of it to cherish your life. These small steps can make you large profits in life whether it’s growing techniques or consuming them.

reuse microgreen soil

Soil And It’s Reuse.

Want to learn more?

If you have any questions about the information cited in this post or about microgreens in general, please leave a comment below or reach out to us via email hello@reactgreens.com.

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