How To Grow Microgreens In Water: The Ultimate Guide

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There are different ways to grow your microgreens and one of them is to grow in water. If the necessary growing conditions are kept, microgreens can be grown in water, without using soil. They are what we call hydroponically grown microgreens where water is the medium that supplies air, moisture, and nutrients to the roots.

But how can you do it? Here’s how you can grow microgreens in water using only nine steps.

How to grow microgreens in water

  1. Select the equipment you’ll want the microgreens to grow in

  2. Set the water

  3. Prepare your grow space

  4. Spread your seeds

  5. Spray mist and light-proof your setup

  6. Check and water as required

  7. Uncover the sprouts and introduce lighting

  8. Monitor daily

  9. Harvest

Growing microgreens in water is a clean process called hydroponics. Growing them in this way means that you ditch the soil and use water instead to precede plant growth.

You can easily grow your microgreens hydroponically in your home and even commercially. However, it requires precision handling and, in this article, you’ll learn how to grow microgreens hydroponically, both for your own consumption and if you are looking to grow on a bigger scale. 

We’ll share the challenges involved, and common mistakes made growing microgreens hydroponically.

How to Grow Microgreens Hydroponically in Nine Steps

Growing microgreens in water might sound challenging, but it truly isn’t. Follow these nine simple steps, and you’ll be well on your way to growing microgreens hydroponically!

1. Select the Equipment You’ll Need

To grow microgreens hydroponically, you’ll require the following:

Growing trays: Depending on how many microgreens you wish to grow, you can buy microgreen growing trays without drainage holes or use any you have at home. Ensure that they’re leach resistant, though, since you don’t want your microgreens to come out smelling like chemicals. Don’t choose a container that is made out of single-use plastic or any other toxic material. 

Growing pads or mats: These provide the medium that the microgreen roots are going to be supported in. They are made out of materials such as coconut coir, hemp, and even Rockwool. You have numerous options, but we recommend natural options like this TerraFibre Hemp Grow Mat.

Seeds: Start with normal seeds but be sure that there are contain no chemicals in them. You’ll be harvesting your microgreens within two weeks, so it isn’t safe to use seeds with chemicals. You can get a Microgreens Seeds Kit to have a variety of viable options to start with.

Fertilizer: As the microgreens will get their nutrition and oxygen from water instead of soil, its recommendable to add fertilizer.

pH tester: You need to check the pH of the water you use on your microgreens, so getting a reliable pH tester is necessary.

Lighting: After a few days of sprouting, your plants will need some light to facilitate photosynthesis. If you plan to grow microgreens in your closet, basement, or anywhere with no access to natural light, you need to get a microgreen grow light. However, sunlight in your balcony, yard, or even kitchen window can be enough.

Spray bottle: When the seeds start, you need to lightly spray your seeds with water as opposed to pouring water. Therefore, a spray bottle will come in handy. 

Nutrients: As the microgreens will get their nutrition and oxygen from water instead of soil, its recommendable to add fertilizer. You can get organic nutrients for your microgreens.

And that’s it! You require the above materials only for a basic setup of microgreen growing hydroponically.

2. Set the Water

Microgreens are extremely sensitive to pH. That’s why you need to measure your water’s pH before using it on your plants. Most microgreens will grow well at a pH between 5.5 and 6.5. Keeping it around 6 is the best idea. You can use vinegar to reduce the pH and baking soda to increase it. 

Before adjusting the pH, make sure the water you use is filtered to get rid of chlorine — or you can simply boil it.

Your water should be all set in advance. Make sure that it isn’t exposed to light so that algae don’t find a place to grow before you’ve even planted your microgreens! You can choose to add nutrients at this step or wait for the seeds to sprout first.

You can check out the following video to see why nutrients matter when growing microgreens in water:

3. Prepare Your Grow Space

Next, take your grow mat and soak it in the water so that it gets saturated. Put it in the growing tray in a way that there’s a little bit of space left in the corners. These spaces will be useful in checking the water content.

4. Spread Your Seeds

Then, take your seeds and spread them one millimeter apart. You don’t want to overcrowd them since that will cause air deficiency and poor drainage. Also, crowding wastes the seeds since not all will have a chance to sprout tall. So, the less the seeds, the better.

5. Spray Mist and Light-Proof Your Setup

Once you’re satisfied with the seed spread, take your spray bottle, which should have the same water you prepared, and mist on the seeds so they can get moisture from the top as well. If you already pre-soaked the seeds, then there’s no need. 

Take the tray lid or whatever you can use to cover the seeds. This will inhibit algae from growing on the mat, plus it’ll enhance the necessary conditions for germination. Ensure that you keep your setup in a warm area and don’t cover the tray completely. Seeds need air to germinate, so your lid should leave some space for airflow.

6. Check and Water as Required

Your seeds would probably sprout in the next three to four days, so you need to check the seeds every 24 hours to see if they need the addition of moisture. If they look too dried up, mist them a little and cover them again.

7. Uncover the Sprouts and Introduce Lighting

On the day the seeds germinate, uncover the tray and expose them to sunlight or grow lights. They need to start photosynthesis and, therefore, should get some light. Pour water at the base of the growing mat in the corners to avoid watering them from the top.

8. Monitor Daily

Ensure that you check on your sprouts daily so that you can water when required and also change the lighting in case it isn’t optimal. Do not use the spray bottle at all in this stage, and don’t let any water come from the top down. It’ll bring mold and mildew issues, so keep watering from the corners while avoiding overwatering as well.

9. Harvest

Once you see the first set of real leaves show up, know that it’s time to harvest. It takes most common microgreens only 9-10 days to become mature, and even the not-so-common ones rarely exceed 15 days. 

You can pluck your microgreens with your hands or use scissors to cut slightly above the growing pad. You may leave the growing mat in place for some days so that the seeds that didn’t grow as tall can lead to a second harvest.

RELATED: The Best Ways to Store Microgreens After Harvest

Growing Microgreens Commercially

While the above steps will do when growing microgreens for your own consumption, a large-scale commercial microgreens business requires more. If you want to take your growing to the next level, here are issues to think about when you want to grow microgreens commercially hydroponically.

Space

If you were growing your microgreens on the window, you have to step up your game and find a bigger growing space. If you don’t have lots of space at your disposal, you can use space-conscious setups to do commercial microgreen gardening.

You can start with space you have in your basement or rooms you don’t use much. This is only for startup purposes as you connect with customers and get your feet wet in this venture. You can use microgreens growing racks or build something yourself. Racks help you grow many microgreens in a small place by maximizing the use of the vertical space.

However, you should be prepared for massive changes within a short time. Since microgreens are short cycle commodities, your customers may need massive product amounts, and you should be ready to expand your business with more growing space.

Automated Hydroponic System

Do you think manual watering will be wasting too much of your time? If yes, then be prepared to build an automated watering system that can supply your microgreens with water and nutrients as per pre-programmed cycles.

You can use the Nutrient Film Technique (NFT), where you pass a form of aerated nutrient solution in your trays during particular times. Once you build such a system, you can leave it for days if nothing malfunctions.

You can also use the Deep Water Culture hydroponic system where you put the seeds in the media and use net pots or perforated trays to suspend them in water. This is an excellent method but isn’t that common in large scale operations. 

Here’s a video of an ideal automated watering system for microgreens:

Pest and Disease Control

A bigger setup has a higher risk of pest and disease infestation. Why? A larger area with closely arranged microgreen trays will make the spread of pathogens fast and easy. Fortunately, you can control it.

Growing microgreens in water help since most hydroponic farmers fail to relate to the disease problems other farmers experience. Therefore, all you’ll probably have to deal with is pests, and depending on the type of pest, you can quickly formulate organic practices that can keep them away. 

Consistency

Since you can produce microgreens all year round, your customers could demand them throughout the year as well. Therefore, you should be ready to be consistent in how you handle the setting up of the best conditions for your microgreens.

For instance, for crops taking two weeks till harvest, you can ensure that you have three batches where one is in the seed stage, another is in sprout stage while the rest are ready to harvest for the next week. Rinse and repeat. Consistency is everything, and you should be ready for it before starting.

13 Mistakes to Avoid When Growing Microgreens Hydroponically

Growing microgreens hydroponically is a relatively new concept, and many growers keep making mistakes that cost them time and money. However, you don’t have to go through the same issues. Here are the top microgreen mistakes you need to avoid:

1. Watering from the Top

You might remember that we recommended spraying water from the top earlier in the article, but when the microgreens sprout, we stated that you should water from the bottom. Well, the reason behind that is to avoid mold.

Spraying water from the top leads to trapping of moisture by the leaves and stems, which may lead to mold development. However, watering from the bottom would feed the roots with the necessary nutrients for growth without dampening the stems and leaves.

2. Keeping the Environment Too Humid

Humidity is essential for microgreen growth. But too much of it isn’t advisable either. You should keep the relative humidity between 30-50% and use a dehumidifier if necessary. Also, you may need to put your air conditioning at work since an increased temperature can increase the humidity of the place to unacceptable levels.

3. Using Unnatural Growing Mediums

Unnatural growing mediums may be cheaper or more readily available in your area. Unless you’re planting the microgreens for your consumption only, going organic means getting a medium that’s 100% natural.

4. Overseeding

Overseeding is one of the major causes of mold. If you spread too many seeds, the microgreens will be placed more closely together than they should be. This inhibits proper aeration and penetration of light and hence creates a haven for mold growth.

Another issue that overseeding can bring is root rot. As the seeds cramp up together, some stay on top of each other, and while the top one germinates, the bottom one rots hence bringing root rot. Therefore, overseeding is more of a waste than an advantage.

You can use a cup to measure seeds each time and adjust as you note the differences. The best thing about measuring the number of seeds you put in a tray is that you’ll get it right, whether there are small or big seeds involved.

5. Confusing Root Hairs with Mold

Before throwing a whole batch of microgreens away, check to see if the “mold” you are noticing is root hairs. So how do you discern root hairs? Root hairs occur on the entire microgreen. Therefore, if you’re growing on a mat, you’ll find all of them containing whitish stuff evenly. 

Some ways that you can tell mold apart from root hairs include:

However, if you notice patches of the white stuff, that’s probably mold.

Another way you can identify mold is if the top of your microgreens has white or other colors of mold, yet the middle part of the stem is normal. 

Since the root hairs remain at the bottom part of the stem, any whitish stuff on leaves and the upper stem is mold.

6. Overwatering

Even when growing microgreens hydroponically, there is still such a thing called overwatering. Unless you’re using an air pump to aerate the water so that it doesn’t go stale, too much water can cause root rot and hence the death of your plants.

If you’re using mats in trays, make sure that if you tilt the tray, the water in the corner reaches your knuckle and nothing beyond. This means you need to add water routinely, so if you’re not prepared for that, you should incorporate an automated hydroponic system like the NFT. 

7. Using the Wrong Seeds

Using treated seeds to grow microgreens is one of the biggest mistakes that cost commercial growers their businesses. One of your customers might get sick from the chemicals, and the security department can show up at your doorstep, asking where you sourced the seeds.

But that’s not the only problem. You shouldn’t buy treated seeds even when planting microgreens for your consumption. It’s dangerous since you can get sick immediately after eating the microgreens or risk diseases like cancer in the long run.

To avoid using the wrong seeds, get certified organic seeds. They have a viable germination rate and are safe according to regulatory standards.

8. Using Non-Food-Safe Plastics

Some people claim that their microgreens smell like chemicals even though they have observed all the organic practices. This is why you should only use food-safe plastics to grow your microgreens.

Plastics can leach lead, among other chemicals, into the water you’re feeding your microgreens. This makes the microgreens unsafe for you and your customers as well. You might even lose microgreen buyers if they discover that your plastics aren’t food safe. 

You can use the Bootstrap Farmer tray that we recommended earlier or try this compostable mini tray that’s FDA-approved.

9. Exposing the Sprouts to Light Too Early

If you wonder why some microgreens look weak and thin, this may be the reason why. Keeping the seeds in the dark for the first few days is essential for their survival, Science Daily explains. As they struggle to get light, they become stronger and yield higher than those that get light right away.

After the seeds germinate, it’s best to leave them in the dark for one to three days. After this, they can easily transition to the vegetative state with the vigor needed for a better yield.

10. Skipping the Sanitization of Your Equipment

If you get your tray from the supplier and you go straight to propagating the seeds before sterilization, you’ll be risking the transference of microbes and chemicals to your microgreens.

After collecting your equipment, wash and rinse it with soapy water. Also, clean the environment you’ll be placing your setup in since it’ll help you minimize pest and disease infestation. Just like a farmer cleans the bushes in the farm before growing crops, you need to do the same when growing microgreens in water.

11. Using Fans to Reduce Mold

It may make sense to aerate the growing space with fans to reduce mold, but unfortunately, it’s a terrible idea. Mold spores get transferred through the air, and if they are driven faster through forced air circulation, they’ll spread to the other trays, and you’ll wonder why you can’t eradicate the mold problem.

The best ways to reduce mold when growing microgreens hydroponically are by:

  • Avoiding overcrowding which may reduce air circulation between the plants.
  • Not spraying liquids on the foliage and watering adequately from the bottom.
  • Decreasing humidity using a dehumidifier and balancing it properly with temperature.
  • Aerating the growing space in an unforced manner.
  • Keeping the growing space clean always.
  • Allowing enough light to the microgreens.
  • Removing any dead matter around your setup.

12. Ignoring pH

If you don’t care about the yield and quality of your microgreens, you can ignore the pH. However, if you like growing healthy microgreens, observe the pH of your water or nutrient solution so that you may facilitate a seamless uptake of nutrients.

For instance, if your microgreens need magnesium and yet your nutrient solution has an extremely low pH, it won’t matter how much fertilizer you put in since it won’t be able to be absorbed. 

13. Starting with Expensive Crops

Even if you’d like to start with a specific crop, but it’s expensive, hold off for a bit. You should begin with easy to grow crops whose seeds are cheap so that you don’t get discouraged if you fail to obtain a successful yield. These things may take time to master for some people, so it’s best not to waste expensive seeds to trial and error.

The Best Microgreens to Grow Hydroponically

You can grow any microgreen hydroponically, but some perform better than others. Here are common microgreens grown in water:

Arugula: Since too mature leaves of this plant become bitter and lose flavor, a great way to enjoy their peppery flavor is through microgreens.

Basil: A micro version of this herb is an excellent addition to salad mixtures since it provides an intoxicating flavor that’s not overpowering like when mature.

Celery: This herb is often either loved or hated for its intense flavor. Celery microgreens provide a middle ground that many people can enjoy.

Kale: A mild taste of kale but full of nutrients, this microgreen can do well in water and is highly sought after in restaurants.

Lettuce: This popular salad ingredient is highly grown in water.

Spinach: Controlling spinach growing conditions is highly essential, so hydroponic methods match its needs.

Cress and Mustard: Being some of the oldest microgreens to be grown, they do well in water as well.

Carrots: Microgreen carrots hold a mild flavor that can easily be developed after a few days of growing in water.

Cabbage: Also a common microgreen, it grows well in water.

So, Why Grow Microgreens Hydroponically?

You must be wondering, why do people seem to love growing microgreens hydroponically? Is there something special about it? The following are the benefits of growing microgreens hydroponically:

It’s a Clean Method

If you can’t stand how messy soil growing can be, growing with water will significantly impress you. Also, since soil growing needs you to dispose of old soil for a new batch, doing gardening in a townhouse or apartment might seem like a far-fetched dream. However, you can grow hydroponically and not worry about disposing of dirt.

You Can Grow Microgreens Anywhere

Gone are the days where you must be in particular areas to do gardening. You can grow your microgreens hydroponically from the basement of your apartment, your balcony, and even a simple kitchen window. Moreover, even if you live in a desert or chilly place, that isn’t a problem since you can create a microclimate. 

You Have More Control

You can control all the conditions you need your microgreens to grow in when planting them in water. You can set the pH and nutrients levels that match the thriving conditions of each microgreen you want to grow. 

It’s Easy to Set Up

You’ve seen it in the above guide to planting microgreens hydroponically, and you must admit that it’s easier than you thought it would be. Even if you want to grow on a large scale, all you need is a more extensive setup with automation features — nothing complicated.

Less Water Gets Used

It can sound counterintuitive when you’re told that growing microgreens in water uses less water than growing in soil, but it’s true. Water gets reused, and hence loss of water remains exceptionally minimal.

You’ll Encounter Fewer Pests and Diseases

Soil has mold problems and is prone to infestation with pests. Therefore, you might have to deal with such problems as chemicals that aren’t that desirable for your consumption and that of your customers. However, since growing with water is generally more contained, good growing habits can give you consecutive high yields without problems of pests and diseases.

Problems of Growing Microgreens In Water

Almost everything that has benefits includes some disadvantages as well. For growing microgreens hydroponically, they include: 

Slower Growth and Lower Yield

Most experiments of growing microgreens hydroponically show that the growth is slower than that of soil. Also, the plants seem to be smaller than the ones grown in soil. However, with a better environment, especially with automation techniques, it’s easier to get a higher yield.

It Demands More Attention

Although soil growing isn’t precisely a set and forgets it kind of gardening, it doesn’t need routine checking of growing conditions. Therefore, soil offers a more stable environment than water. 

Conclusion

Growing microgreens hydroponically is a fantastic growing method. You get the nutrient-full product without making messes and even have an opportunity to start a business using extra space in your home. Moreover, it’s simple to do, and if you follow the above guidelines, you’ll experience success from the start. It’s up to you now!

Microgreens Corner
Microgreens Corner
We are Janette & Jesper, and we love microgreens.

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