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I’ve been involved in hydroponics for a while now. And, as I was enjoying a delicious curry the other day, I looked down at my plate and wondered – could you grow rice in hydroponics? My curiosity got the better of me. And so, I did some detailed research and what I found.
You can successfully cultivate rice in a hydroponic system by carefully managing nutrients, water quality, aeration, temperature, humidity, and pest control. However, it is one of the least efficient crops to grow hydroponically, with a long growing time and low yields.
In this guide, we’ll explore exactly what you need to consider before growing rice in a hydroponics system, and even question whether or not you should do it (it’s hard!). We’ll also explore the steps you need to maximize your chances of success – good luck!
Things to be aware of before growing attempting to grow rice in hydroponics
While it’s possible to grow rife hydroponically at home or on an industrial scale, you should be aware that it is not an easy endeavor. Before you start, I want to make you aware of a couple of key points that may end up saving you quite a lot of time and effort:
1. Growing rice hydroponically results in low yields
Compared to conventional rice paddies growing rice produces far less yield. It’s near impossible to replicate the density of growth in hydroponics. This means that, depending on the size of your hydroponics system, you should expect overall crop production to be low (and possibly not worth it).
2. Growing rice takes a lot of time
Another factor to consider is that growing rice to maturity takes a lot of time. Around 180 days, to be exact. Remember that if you choose to proceed with growing rice in hydroponics you are making a 6-month commitment.
3. Grow rice at small scales is a money sink
If you were hoping to cultivate hydroponic rice to sell you might as well forget it. The low price of the end product, coupled with the relative expense of hydroponics (and the low yields outlined in point 1) make it an economic pitfall. Unless you’re an industrial hydroponics farmer, don’t expect to make any money by growing rice hydroponically.
Ready to start growing rice hydroponically? Here are some key considerations before you start
Choosing the right rice variety for hydroponics
Several rice varieties can be grown successfully in hydroponic systems. Choosing varieties with short growth cycles, high yields, and good disease resistance is generally a good idea. Consider the environmental conditions of your area too, especially if growing outside.
Some potential varieties could include:
|Time to harvest (days)
Experimenting with different varieties can help identify the best-performing types for your specific setup.
Selecting the right hydroponics system for growing rice
The best hydroponic system for growing rice is a flood and drain (also known as ebb and flow) system. This system mimics the natural wet and dry cycles that rice plants experience in traditional paddy fields.
Read more about flood & drain hydroponics systems in my article about the different types of hydroponics systems (with diagrams).
In a flood and drain system, the nutrient solution periodically floods the grow tray, allowing the rice plants to access water and nutrients, and then drains away, providing essential oxygen to the roots.
You can also attempt to grow rice via Deep Water Culture (DWC) or Nutrient Film Technique. Essentially, any system that more closely mimics the rice as it would grow within a traditional paddy field. These three systems replicate the ‘water-logged’ environment rice loves.
Considering the environmental factors for optimal hydroponic rice growth
When growing anything in hydroponics it’s important to be aware of the environmental factors that influence the growth and quality of your intended crops.
- Light: Rice plants require about six to eight hours of light each day for photosynthesis and growth. A combination of natural sunlight and artificial light sources, such as LED grow lights, can help maintain optimal light levels. However, if using artificial light only, try to mimic day/night cycles and ensure your lights are on for at least eight hours each day.
- Temperature: Rice plants thrive in warm temperatures, ideally between 70-98°F (21-37°C). Maintaining this temperature range in a hydroponic system is essential for optimal growth.
- Humidity: A relative humidity of 60-80% is ideal for rice cultivation, promoting proper transpiration and minimizing the risk of fungal diseases.
- pH Levels: Rice plants grow best in a slightly acidic environment, with a pH range of 5.5 to 6.5. Regularly monitoring and adjusting pH levels is crucial to maintain healthy plant growth.
Step-by-Step Guide to growing rice hydroponically
Step 1: Choosing the right rice variety
Different rice varieties have unique characteristics, such as growth duration, resistance to pests and diseases, and nutritional content. Select a rice variety that is well-suited for hydroponic cultivation (as listed above) and the local environment in which you plan to grow it. It’s important to consider environmental factors such as temperature before choosing.
Step 2: Germinate rice seeds
To start the rice cultivation process you should generally kick off the germination process by soaking the seeds in water for 24-48 hours. Once done, transfer the seeds to a tray filled with a moist growing medium, such as coconut coir or perlite. Keep the tray in a warm (check the rice varieties temperature requirements), dark place and maintain humidity until the seeds sprout, which usually takes 7-10 days.
Step 3: Transplant rice seedlings
Once the rice seedlings reach a height of about 2-3 inches (5-7.5 cm), they are ready for transplanting into the hydroponic system. Be very gentle! Remove the juvenile plants from the growing medium. Take extra care not to damage the roots. Place them into a hydroponic system, ensuring that their roots can get access to the nutrient solution.
Step 4: Monitor and adjust nutrient and pH levels
Regularly test the pH and nutrient solution to ensure that it maintains the appropriate concentrations of essential elements. Adjust the nutrient mix as needed to prevent deficiencies or imbalances that could affect rice growth. To test the solution and pH levels, purchase a decent testing meter from Amazon.
Step 5: Maintain optimal environmental conditions
Monitor and control the environmental factors that impact rice growth, such as light, temperature, humidity, and pH levels. Adjust these factors as necessary to create the ideal conditions for healthy rice plants. Ensure you research what the optimal conditions are for your chosen variety.
Step 6: Plan to manage pests and disease
Keep a close eye on your rice plants to detect any signs of pests or diseases. Implement strategies, such as chemical or organic pesticides, to minimize the risk of infestations and maintain a healthy crop.
Step 7: Harvest and process rice
Once the rice plants have reached maturity (check the harvest time for your chosen variety), harvest the grains by cutting the panicles. Dry the harvested grains to reduce their moisture content, and then mill them to remove the husk and bran layers, if desired.
The biggest challenges of growing rice hydroponically (and their solutions)
There are many challenges with growing plants hydroponically. Growing rice hydroponically, in particular, is fraught with challenges. But while it does require a fair amount of time and effort, it is possible to overcome them with the right approach and a little patience.
Keeping the roots well-aerated
Rice plants need adequate air and oxygen at their roots for proper growth and to help prevent diseases. Poor aeration of the root system can lead to stunted growth and even root rot.
Check out my related article: Why aren’t my roots growing in hydroponics?
To increase the levels of oxygen in the nutrient solution, and root aeration, use air stones or diffusers in the reservoir.
Maintaining a balance of nutrients
As with all hydroponically grown plants, rice requires a balanced nutrient solution to grow and thrive. Regularly monitor and adjust the nutrient solution using a nutrient meter (I use the YINMIK 3-1 Hydroponics Meter which is cheap and effective), and do some detailed research into the recommended nutrient concentrations for your selected rice variety.
Preventing algae build-up
Another issue with hydroponics in general, particularly in ebb and flow and other hydroponics systems suitable for growing rice, is the build-up of algae and other contaminants in the reservoir. Algae buildup can clog pumps, and pipes and even starve your rice plants of oxygen.
Check out my article all about how to prevent and remove algae buildup in hydroponics.
Managing pests and diseases
Again, like all hydroponically grown crops, rice is vulnerable to pests and diseases which can negatively impact plant health and productivity. Dealing with pests can be a challenge. But there is a range of both chemical and non-chemical solutions available on the market (I tend to steer clear of chemicals).
How to know when your hydroponic rice is ready to harvest
Once rice plants have reached maturity, which typically occurs between 100-120 days after germination, they are ready for harvest. Harvest the rice grains by cutting the panicles (clusters of grains) with a sharp knife or scissors. You’ll also need to manually thresh the rice grains from the rest of the plant.
After harvesting, the rice grains should be dried, either in the sun or using a mechanical dryer, to reduce their moisture content to approximately 12-14%. Once dried, the grains should be milled to remove the outer husk and bran layers, resulting in polished white rice.
The short video below shows you one technique that can be used to de-husk rice at home.
Some final thoughts
Growing rice in hydroponics is hard. However, by following this guide and implementing the tips and strategies discussed in this article, you can successfully grow rice in hydroponics at home and will soon be able to enjoy the numerous benefits of this innovative cultivation method, and the satisfaction of eating your own home-grown rice.
If you manage to grow rice successfully then I’d love to hear from you. Please send me an email! You can find my contact details under the ‘About me’ tab on the homepage. Good luck!