How To Grow Rice Hydroponically

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By Chris Lipsey

Rice is one of the world’s most important crops as it is a staple for millions if not billions of people. This being said, it is also an extremely tricky crop to grow outside of its natural environment.

The crop requires lots of water, constantly sunny conditions, and heat. These combined elements make it very difficult to grow rice in most regions of the USA. But not impossible. For most growers, growing a rice crop will likely be for self-interest and not for sustenance.

Rice also requires a lot of space to produce enough for a family. If you do have a large area and live in an incredibly humid area with a dramatic amount of rainfall, you could consider growing it in the backyard.

But, this all being said, wouldn’t it just be easier to grow this crop hydroponically? The simple answer is yes. And while it is still in its infancy, we think it would be a great candidate for industrial hydroponics.

Let’s talk more about the perfect conditions for growing rice.

Related: Most Popular Hydroponic Vegetables

Perfect Conditions for Growing Rice Hydroponically

As a staple crop, planting it is not a challenge (harvesting is where it gets tricky). If you are growing your own rice, you will need to plan for at least 40 days of continuous warm temperatures of at least 70°F.

While rice plants don’t need much care when growing, they have certain requirements that must be seen to, such as having at least two inches of water above the soil. When the plants develop over five to six inches tall, you will need to up the water level to four inches.

Then over the rest of the lifespan of the plant, you should reduce the water level slowly until harvest time, when the plant should not be standing in water at all.

However, while many rice varietals need to be grown in water, some don’t require being submerged.

Rice takes around four months to go from seed to harvest ready. When the stalks turn a golden color this is an indication that it is ready to be harvested.

When harvesting, you will want to cut the stalks and wrap them in newspaper and allow them to dry out completely for two to three weeks. Once the rice has dried out, roast them at a low oven temperature for an hour. Finally, you need to remove the hulls by hand, and you will get perfect rice for you and your family.

Even though this is a crop that spends most of its life submerged in water, it is actually quite challenging to replicate that environment within a hydroponic system. So, what elements do you need to be aware of when growing rice hydroponically?

What You Need To Know When Growing Rice Hydroponically

A major bonus for rice to be grown hydroponically is it will use less water and space. According to Rice Today the advantages they discovered were:

  • The hydroponic seedlings recovered quicker, produced tillers more vigorously, matured at the same time, and had a higher yield
  • Crops matured faster
  • Used 95% less water
  • Was good for late monsoon
  • Hydroponic systems promised a more uniform crop

And there are multiple types of rice that can be grown.

These include:

  • Basmati Rice
  • Wild Rice
  • Jasmine Rice
  • Stocky Rice
  • Valencia Rice
  • And Rosematta Rice

All these grains of rice need different growing conditions, but generally speaking, they all require loads of sunlight, heat, and humidity.

They all need at least 10 hours of sunlight.

Rice is pretty resilient to pH changes, surviving well in anything between 3.5 to 8.5 pH. And due to the fact that rice is grass, it thrives on nitrogen. Out of all the nitrogen fertilizer options, the best to focus on is ammonia-based nitrogen, which is abundant in urea and urine.

When feeding your rice, also make sure not to neglect feeding potassium and phosphorous too.

And as it is grass, there’s no need to prune your crop. Rice also loves a fertile growing medium, tapping into rotting material. One plant will produce between 70 to 100 grains of rice.

Now that we’ve covered the basics let’s focus on what hydroponic system you’ll need to grow rice.

Selecting A Hydroponic System For Rice

While most will assume growing rice in a deep water culture (DWC) would be best, it’s not always the most efficient option. In fact, hydroponic systems like the nutrient film technique (NFT) have been highlighted as the method to use.

NFTs allow for the seedling trays to tap into a nutrient-rich solution. In NFT systems, the water levels rise and fall. Mimicking rice’s natural environment. Also, a mixture of water and air makes it a perfect system for rice, protecting the plant’s roots from overexposure to the sun.

Also, NFTs allow for large scalability.

For those not keen to utilize an NFT system, you can also use one of the following hydroponic systems:

Static Solution Culture

The technique’s name indicates that the solution is static, so the plants just float in it. It is the simplest form of hydroponics.

Nutrients are fed into the reservoir and used when the plants need them. The only maintenance required is to stir the solution periodically. While the roots of most plants would suffocate over time, rice is more tolerant to lower levels of oxygen.

This being said, make sure the roots are exposed to some air.

Continuous Flow System

Again, pretty self-explanatory; water is piped around the system for the whole day. You will need to ensure that the roots are in constant contact with the nutrient solution.

This constant motion also ensures that the water is oxygenated.

Ebb and Flow Hydroponics

With an ebb and flow system, the water flow is turned on and off to drench the roots of the plants. The plants are placed on top of a tray, and the water flows underneath.

While you could use aeroponics, aquaponics, and fogponics, these require more maintenance and setup costs. Aeroponics and fogponics sprayers can get clogged and cause issues, while aquaponics requires keeping fish alive.

So overall, we’d strongly suggest sticking with an NFT.

Now, let’s focus on the steps you need to follow to grow rice hydroponically in an NFT system.

How To Grow Rice Via An NFT System

Before setting up the actual system, you need to do some seed preparation. Germinating seeds requires soaking them for at least 36 hours and then allowing them to dry out for an entire day.

Germinating the seeds can take place in a bucket with a potting medium that has a 50/50 split between soil and compost. Germination should take around two weeks.

When the seedlings are around two to three inches high, wash off the growing medium and pot them into the system. The hydroponic growing medium can be rice husks.

Make sure that the temperature is kept at 77°F to ensure that the rice develops quickly, and keep the grow light for ten hours a day. You should invest in a full-spectrum LED grow light to cut down on electrical costs.

When the rice starts to turn golden in color, it’s time to harvest.

Growing Rice Hydroponically Is Possible

While it is possible to grow rice hydroponically, the scale you’ll need to make it profitable is immense. A lot of research is being put into growing rice hydroponically, as it will save water and time.

For now, if you are interested, have fun and experiment.