Plant lovers and environmentally-conscious people are coming up every day with new, creative ways to promote sustainable wastewater management techniques. Households generate plenty of wastewater from the kitchen, including liquids used for cooking, such as rice water. One common way to repurpose cooking or kitchen wastewater is to use it in the garden.
Rice water is good for plants because it contains numerous essential nutrients for your plants and beneficial microorganisms. However, there are several ways to make rice water, and not all of them can provide equal benefits to your garden.
Further on, we will discuss some essential elements to know about rice water and how some gardeners came to the idea that it can be used on plants. We’ll also be looking into how to use rice water on your plants, along with the practice’s pros and cons. Let’s begin!
4 Things To Know About Rice Water Before Using It on Plants
Rice water is a wastewater material common in Asian households where families cook rice almost every day. Many American and European homes also prepare rice meals every now and then.
Over a hundred countries consider rice a staple food, and you can only imagine the large volume of rice water generated in each household. It undoubtedly led some families to find alternative ways to reuse it instead of just disposing of it.
That’s essentially how some gardeners found other wastewater sources like laundry and soapy water to be useful in the garden.
1. There Are Several Ways To Make Rice Water
Rice (Oryza sativa) is found in numerous countries and comes in several varieties. Each variety requires a different way of preparation or cooking due to their varying consistency and nutritional contents.
For instance, people soak rice for several hours to reduce the cooking time required. In other cases, some rice varieties may be sticky due to the different types of starch they contain and thus, require a different mode of preparation.
As a result, different rice varieties can generate different nutrients and produce varying levels of effectiveness when it comes to plant growth and overall health.
The most important element to keep in mind when thinking about utilizing rice water on plants is that the preparation method matters.
Water From Washing Rice
In many Asian homes, families rinse the rice in cool water to remove dust and dirt. The resulting cloudy rice washing, which contains mainly dirt, starch, and a few nutrients, is then flushed down the sink.
One washing is often enough, but some people might find it necessary to do it twice, depending on how dirty the rice looks. Some people may also be worried about the amount of arsenic in the grains. Brown rice is more likely to contain higher levels of arsenic from the ground than white rice.
However, it helps to remember that rinsing the rice multiple times risks also washing away some essential nutrients, which can be suitable for plants.
On the other hand, washing the rice shortly before cooking and skipping the soaking part will require more water and a longer cooking time. However, even if you don’t soak the rice before cooking, it doesn’t necessarily affect the flavor or texture, especially with some white, long-grained rice varieties. The difference in taste is often subjective.
Many Southeast Asian rice varieties like Jasmine from Thailand do not require soaking because the excess water will result in a soupy or soggy consistency.
Regardless of whether you plan to soak the rice or not, it is essential to rinse it first. This is the easiest way to harvest rice water.
Water From Soaking Rice
Some rice varieties, especially the colored ones like red, brown, or black rice, often require a soaking time ranging from thirty minutes to overnight. These rice varieties are typically drier and harder, requiring hydration prior to cooking. Otherwise, you will need double or triple the amount of water and time necessary to cook them.
Typically, short-grained and glutinous varieties require a longer soaking time than long-grained rice varieties. A 10-15 soaking time is enough for Indian rice like Basmati.
Short-grained Chinese and Japanese rice must be soaked for a maximum of 30 minutes because soaking the rice for longer will remove too much starch, making the cooked rice less sticky.
Moreover, soaking the rice overnight can break down phytic acid, which binds with nutrients like iron, calcium, and zinc, preventing them from being absorbed by the body. This is due to the lack of enzymes in the human body that would otherwise enable us to digest phytates – substances formed from the bonds between phytic acid and essential nutrients.
Water From Cooking Rice
Suppose you’ve been cooking the same type of rice for several years. In that case, you most likely already know the ideal water-to-rice proportion to achieve the best consistency and texture in your cooked rice.
On the other hand, if you haven’t tried cooking a new rice variety yet, you may need to go through some trial-and-error to find the best proportion. I recommend putting in more water than necessary and pouring out the excess to avoid checking up on your rice frequently.
This excess water typically contains several nutrients; some people cool it down before pouring it into their garden soil.
The heat from cooking the rice can break down some substances through a chemical reaction, releasing nutrients that are different from rice water that comes from rinsing or soaking.
2. Rice Water Contains Plenty of Nutrients
Every experienced gardener knows that every plant has unique nutritional requirements. For instance, flowering plants typically need plenty of potassium, while foliage plants require less potassium and more nitrogen.
It can be pretty challenging to determine how much of each kind of nutrient is present in rice water. The kind and quantity of nutrients depend largely on the following factors:
- Rice variety
- Nutritional qualities of the soil where the rice was grown
- Processing, packaging, and transport method
- Mode of preparation of rice water
Even if you prepare rice water the same way from the same rice variety, there will still be inconsistencies in the nutritional content of the liquid. Nevertheless, several rice varieties have varying levels of the following essential plant nutrients:
- Nitrogen
- Phosphorus
- Potassium
- Calcium
- Magnesium
- Manganese
- Zinc
- Iron
You will need to send your rice water sample to a laboratory to determine the actual levels of these nutrients in rice water. Of course, that will be costly and impractical.
With that in mind, it is best to treat rice water as a nutritional supplement and not as a complete alternative to fertilizer for plants with specific nutritional requirements, especially during the growing season.
3. Some Asian Parents Feed Their Babies Rice Water
Before arsenic poisoning from rice grains and rice-based products like cereals became a global issue, many Asian parents, especially in Southeast Asia, used to feed their babies rice water.
Anecdotal evidence claims that babies fed with rice water had better immune systems and were smarter. Because of this, some Asian parents in rural areas still feed their infants rice water as they transition from breastfeeding to rice cereals.
Although there isn’t enough research to prove these claims, the benefits of feeding rice water to babies can be attributed to the liquid’s nutritional contents – the same reason gardeners use rice water on their plants.
It is important to note that rice water used for feeding babies is prepared from cooking rice. Rice water from rinsing or soaking is unsafe for babies due to the high risk of microbial infection.
Rinsing also washes away arsenic and other harmful chemicals from the rice grains. The downside of this method is that you may be reintroducing arsenic into your garden. This should be fine as long as you don’t use the rice water on edible crops.
On the other hand, cooked rice water is unlikely to contain harmful microbes because the high heat followed by simmering required to cook rice is enough to eliminate them.
Old research from Singapore also recommended the use of cooked rice water in treating gastroenteritis among infants, especially in areas in developing countries that don’t have access to adequate treatment.
Scientific evidence on the nutritional content and safety of rice water on babies supports the idea that the liquid can be repurposed for other uses, such as gardening.
4. Some Rice Water May Contain Salt or Broth
If you’ve been to an Asian or Spanish restaurant, you may have already come across several flavored rice dishes. In addition to the typical plain white rice, you can find rice cooked with a dash of salt. Some recipes even replace water with broth.
You can use the rice water from rinsing and soaking for your garden, but it’s best to avoid using the flavored rice water after cooking. Too much salt is bad for the plants as it may cause dehydration, especially if you plan to use salted rice water on potted plants. To learn more about the impact of salt on plants, you can read my other article: Can Plants Survive if They Get Salt on Them?
On the other hand, the aroma of the broth may attract insects, microbes, and even house pets to your pots or garden. So if you plan to use rice water on your plants, you might as well use pure water to cook rice and avoid the additives altogether.
How To Use Rice Water on Plants
As discussed, there are several ways to prepare rice water. Assuming that you’re going to perform all steps from rinsing, soaking, and cooking, you can follow the suggestions below on how to use rice water on your plants:
- Rinse the rice. Using cool water from the tap, fill the rice container with enough water to cover it up to an inch (2.54 cm) above the surface. Stir the rice to remove dirt, but avoid squeezing the grains.
- Collect the water in a separate container. It’s okay if you want to rinse the rice several times. Be sure to collect the water in the same container every time you drain the rice.
- Pour the rice water from rinsing into the soil. Be mindful of your plant’s water requirements to avoid over-watering.
- Collect the rice water from soaking. You can use this water on another plant or pour it directly on your garden soil.
- Cool down the cooked rice water. Pour the cooked rice water into a container with a lid to prevent microbes and pests from getting to the liquid as it cools down. Wait until the rice water reaches room temperature (approximately 77 °F / 25 °C) before using it on your plants.
Things to Remember When Using Rice Water on Plants
- Avoid pouring rice water on the leaves. Letting the starch in the solution sit on the leaves can invite unwanted pests to your plants. Allow the nutrients to seep into the soil to be absorbed by the roots or to feed the helpful microbes.
- Pay attention to your plant’s watering needs. If you cook rice every day, avoid watering the same plant with rice water as often. Instead, you can use the rice water to feed other plants or pour it on bare garden soil to enrich it.
- Alternate rice water with pure water. Providing your plant with purified water between rice water feedings can help leach out any excess nutrients from your pot. It can also help rinse your soil of white suds from the rice water.
Benefits of Using Rice Water for Plants
When collected and applied correctly, rice water can be beneficial to plants. Check out the benefits below:
It Provides an Eco-Friendly Way To Dispose of Rice Water
One-time preparation of rice can generate at least a liter (33.8 fl. oz.) of rice water from rinsing, soaking, or cooking. Instead of flushing water down your drain, you can collect it and pour it on your garden soil.
You can use it directly for your gardening needs without having to treat it along with other wastewater sources.
Rice Water Doesn’t Cause Fertilizer Burn
The low levels of nutrients in rice water can supplement your plant’s needs. They are not potent enough to cause fertilizer burn, especially if you follow the recommended frequency of application. Moreover, pouring rice water on the bare ground before planting can enrich your soil.
A Small Volume of Rice Water Is Safe for Plants
Rice water is beneficial whether you have a small or a big garden. The small volume of rice water won’t saturate your garden soil. You can use it on a few potted plants at a time and easily rinse it off with pure water in the following watering session.
However, if you have only a few indoor potted plants, you may need to throw away some rice water. You may feel bad about it, but it can be harmful to force it on your plants too often.
Disadvantages of Using Rice Water for Plants
Based on the information provided above, it also helps to pay attention to the disadvantages of using rice water for plants. It can help you decide whether or not you want to give it a try. And if you do, this information can help you come up with ideas to overcome these issues.
Rice Water Can Boost the Growth of Harmful Microorganisms
The starch in rice water can also feed harmful microorganisms in the soil, compromising the health of your plants. Using rice water can be counterproductive, depending on the type of microbes and the health condition of your plants.
How To Overcome
While there is no way to discriminate among microorganisms as to which can feed on the rice water, you can limit the number of times you provide your plants with the liquid. If your plant requires weekly watering, you can use rice water every two weeks and feed your plant distilled or purified water in between.
You can also boost your plants’ health through other means, such as providing adequate sunlight and nutrients. This can help them become sturdier and less susceptible to microbial infection.
Dried Starch Suds Can Attract Pests
When you harvest rice water from rinsing, soaking, or cooking, you will notice white suds floating on top. Ideally, you shouldn’t throw them out because they contain starch and other nutrients your plants may need.
However, once the water dries up and leaves behind these white suds, you may notice tiny insects gathering around your plant. You may even find cockroaches because they are attracted to starch.
How To Overcome
You can use physical pest repellents like sticky paper to prevent cockroaches and other insects from getting to your plants. Avoid using pesticides because the chemicals may be toxic to your plants. You can also scrape the dried-up white suds on the surface of your soil.
Final Thoughts
Rice water is good for plants as long as you know how to collect it properly. It’s also essential to remember that rice water is not a perfect alternative to fertilizer because it can be challenging to identify and measure the nutrients present in the liquid.
Be sure to follow the tips above on how to use rice water on your plants to maximize its benefits without compromising your plants’ health.
