What are Rice Hulls?
Rice hulls are one of the most sustainable soil amendments available for improving drainage, water holding capacity and aeration. Unlike perlite and other rock products, it does not require mining; unlike peat moss it does not require land disruption to produce it.
Like coco coir, it’s a byproduct of agriculture that would otherwise be considered waste. Rice hulls are the husks that are removed from each grain of rice after harvest. The hulls are then parboiled at a high enough heat to sterilize any grains of rice that found their way into the mix, as well as weed seeds and diseases.
Rice hulls are nontoxic and biodegradable, so they feed the soil as they break down. However, they are stable enough to last for the typical gardening season before decomposing, so the soil will enjoy the benefits of moisture regulation and aeration while your organic vegetables grow. Check out our rice hulls at here.
Using Rice Hulls in Your Garden
- For your garden soil, spread about a two" layer across the surface when you fertilize in the spring, and mix it into the top 6–12" of soil.
- For potted plants, you should mix 10–50% rice hulls into the potting soil.
- Rice hulls can be used as a mulch for your bedding, similar to how you would use straw.
- Rice hulls are extremely lightweight, so they’re especially ideal for rooftop gardening or other gardens that require an amendment to make your soil lighter.
Comparison of Rice Hulls with Other Soil Amendments
- Rice hulls are most similar to sphagnum peat moss and coco coir, but are more sustainable than either.
- Somewhat less effective at aeration and water retention than peat moss or coco coir, but still a good choice–and if your soil surface is “extra bad” you can compensate for the difference by adding just a little more rice hulls than you would have coir or peat.
- Unlike these similar products, it is neutral pH. Peat moss and coco coir are both acidic, so use them on acid loving plants or if your soil has a high pH. Use rice hulls if your soil is the correct pH for your plants already, or is naturally acidic.
- Unlike perlite, pumice, vermiculite, and biochar, rice hulls break down after one season of use. This is good for adding organic matter for your vegetable garden, but you will have to reapply it annually to get the other benefits of moisture regulation and aeration.
- Rice hulls are also less dusty than mined soil amendments, and the natural color blends in better with the soil than the grays and whites of pumice and perlite.
