Rice water fertilizer - Ask Extension
How to make rice water fertilizer? What is the application rate and how often can I use it? They are too many gardening hacks online and I don’t k...
Knowledgebase
Rice water fertilizer #862689
Asked March 28, 2024, 7:34 AM EDT
How to make rice water fertilizer? What is the application rate and how often can I use it? They are too many gardening hacks online and I don’t know which one to believe in. Thanks.
PS: I cook rice all the time. Rice water is ready available to me.
Baltimore County Maryland
Expert Response
UMD Extension does not have research in the home use of rice water (either from rinsing raw rice or water leftover from cooking rice) for indoor or outdoor plants. However, we did locate a relatively recent study that appears to demonstrate some benefit for plants, at least in certain circumstances. The full research paper title is: Consecutive Application Effects of Washed Rice Water on Plant Growth, Soil Chemical Properties, Nutrient Leaching, and Soil Bacterial Population on Three Different Soil Textures over Three Planting Cycles, and it is accessible to read online on the linked page.
Water used to prepare rice can contain nutrients that can benefit plants as a fertilizer, but there are few studies on this topic. The amounts of nutrients will vary greatly depending on soil characteristics, rice variety, location of the rice production area, cooking method, etc., so we are not able to provide a specific recommendation for its use. Plus, the study above used actual soil, not a soilless potting mix (in case you were curious about its use on houseplants), so the findings of that study might not apply to indoor plants that are not grown in soil since that substrate has different drainage, acidity, and nutrient-retention properties.
As an added consideration, heavy metals (especially arsenic) are easily taken up from the soil by rice plants. Heavy metal contamination of rice can vary greatly. This is a big problem in parts of the world where soils are contaminated from mining and other industrial sources.
We realize that using rinse water would be a more sustainable use of the water and the leached nutrients, but in the case of indoor plant growing or using the water to irrigate food plants outdoors, it may be simpler to use a fertilizer product (organic or otherwise) with a known nutrient content and dosage instructions. Using rice water to irrigate non-edible plants outdoors might be fine, but we have not researched this locally to date to determine what other pros or cons may result.
Miri
Water used to prepare rice can contain nutrients that can benefit plants as a fertilizer, but there are few studies on this topic. The amounts of nutrients will vary greatly depending on soil characteristics, rice variety, location of the rice production area, cooking method, etc., so we are not able to provide a specific recommendation for its use. Plus, the study above used actual soil, not a soilless potting mix (in case you were curious about its use on houseplants), so the findings of that study might not apply to indoor plants that are not grown in soil since that substrate has different drainage, acidity, and nutrient-retention properties.
As an added consideration, heavy metals (especially arsenic) are easily taken up from the soil by rice plants. Heavy metal contamination of rice can vary greatly. This is a big problem in parts of the world where soils are contaminated from mining and other industrial sources.
We realize that using rinse water would be a more sustainable use of the water and the leached nutrients, but in the case of indoor plant growing or using the water to irrigate food plants outdoors, it may be simpler to use a fertilizer product (organic or otherwise) with a known nutrient content and dosage instructions. Using rice water to irrigate non-edible plants outdoors might be fine, but we have not researched this locally to date to determine what other pros or cons may result.
Miri
