Water chestnuts are delicious tubers, which are primarily cultivated and eaten in China. Normally found canned at the supermarket, it’s possible to grow water chestnuts yourself. All you need is a starter plant, a bucket, soil, water, and some patience.
Keep in mind that it is a water plant, so growing water chestnuts might be a whole new experience for you. Keep reading to learn all about water chestnuts and how to grow them yourself at home.
What are Water Chestnuts
If you’re wondering what are water chestnuts, you’re not alone. Water chestnuts are the tubers of the Eleocharis dulcis plant, which is an annual sedge in the Cyperaceae family. Although they are not commonly grown in home gardens, water chestnuts are an extremely versatile plant.
The edible tubers, typically found in Asian dishes such as stir-fries, add a crunchy texture and sweet taste. They are also used in herbal medicine due to the presence of a penicillin-like antibiotic called punchin in the corms. The grassy foliage can be used as mulch or in crafts such as basket weaving and in tapestries.
The name water chestnut comes from its resemblance to chestnuts. Only that instead of growing in a Chestnut tree’s spikey pods, water chestnuts grow under wet, flooded soil. The plant tops look like tall grass and are typically found growing in Asia, India, and Oceania.
How and where are water chestnuts typically grown
Water chestnuts are typically grown in China, where complicated irrigation systems are used to control a specific watering schedule. They also need a seven-month growing season, limiting their commercial cultivation to China. Attempts at commercial water chestnut cultivation haven’t been financially feasible in the United States.
In China, the chestnuts are started in nurseries under wet conditions to get a month’s headstart. Then they are planted out in a flooded field and left for six months. Once mature, the fields are drained and the water chestnuts are harvested by hand.
Water chestnuts are peculiar plants, requiring specialized conditions, so they are only grown commercially in China and a bit in Australia. The good news is that growing water chestnuts on a small scale is totally doable. Small scale growing can be done in containers and/or inside, which helps to control the growing conditions. Keep reading below to learn how to grow water chestnuts at home.
How to grow your own water chestnuts at home
To grow your own water chestnuts at home you’ll need seed chestnuts, a large container, soil, compost, and water. You’ll also need a bit of patience and a long growing season. If you have over 7 months of warm weather (USDA zones 8 and above), you’ll be able to grow your water chestnuts outside. If your growing season is shorter, make sure you have a plan in place to bring your container inside for the fall.
Start with a seed corm
To grow water chestnuts, start off with a seed corm. You can either purchase a freshwater chestnut from a specialty food (canned ones won’t work) store or order it online. Before you buy your seed corm, consider the volume of your growing container. You’ll need one corm per square meter – each corm will spread and multiply a surprising amount.
Once you have your corms, you’ll need to plant them into some sort of container. You can also plant them in a pond-like area of your garden or have containers floating in a natural pool. But growing water chestnuts in the ground can be more logistically complicated. I recommend you start by using a 5-gallon bucket, 20-gallon drum, plastic pool, or my personal favorite – an old bathtub.
Add to a limey soil mix
Then fill your starter container of choice with limey soil mix. In China a clay-heavy soil is used, but when the field is drained it clumps up. Instead, use a sandy soil mix that will make it easy to hand-harvest the corms. I like to use one part compost and one part perlite to start the seed corms and then switch to a looser mix for the growing season.
Use this soil mixture to fill your starter container. It should have drainage holes like a regular plastic pot within three inches of the edge. In the middle of the soil, open a space four inches deep and plant the corm. Then cover it up with the soil medium, water thoroughly, allowing the excess water to drain out.
Leave your corm to get established in this plastic pot until the leaves are 8 inches tall. The soil mix should stay consistently moist during this time, but if it’s overly wet the corms will rot.
Transfer to main container
Once the corms have established roots and have grown leaves, it’s time to transfer them to their permanent growing container. This 2nd container should have no drainage holes.
You’ll fill this container with a looser mix made up of two parts compost, one part builders sand, and one part perlite. Your container won’t let water drain, so don’t worry about the large percentage of sand.
Always keep this container flooded with two inches of water above the surface during the growing season. Maintain it heavily saturated with water for the next 6-7 months until the corms are ready to be harvested.
How do I harvest and store water chestnuts at home
You can harvest and store your water chestnuts after about seven months when the leaves die back. To harvest, drain the water from your container first.
Then lift up the root ball out of the container and place it somewhere where you can gentle rinse and untangle it. Gently separate out the corms from the roots and you rinse and untangle. Just wash the separated corms so they’re free from any dirt and they’re ready to eat!
Storing your water chestnuts
To store water chestnuts at home, refrigerate them in brown paper bags. Whatever you can’t eat within 10 days should be stored in the freezer. Store your water chestnuts by putting them unpeeled in air-tight bags in the freezer. They’ll stay good for up to six months.
Next years seed corms
Make sure to save some corms for next year’s planting though! To store these freshwater chestnut corms, keep them in a container of damp sand over the winter. Next spring, you’ll have as many corms as you need for your new planting.
What are the difficulties with growing your own water chestnuts
Water chestnuts need very specific irrigation. They require that the growing medium be flooded for their 7 months growing period. Be careful not to over-saturate the soil with water while the corms are growing or they’ll rot. At the same time, it’s important to maintain the water level two inches above the soil during their growing season.
Growing water chestnuts requires you to flood your container, leaving standing water for several months. These are prime conditions for mosquitos, which may lead to an unfortunate infestation. Grow lemongrass plants around the water chestnuts or introduce frogs into your garden for a green anti-mosquito solution.
If your soil is too acidic, it might cause your water chestnut plants to develop fungal growth on the stems. This is the only disease that seems to affect water chestnuts, so prevent it altogether with the right soil. Use bagged potting soil, limey soil, or amend your acidic soil with dolomite if necessary.
Water chestnuts are a delicious and nutritious delicacy that can only be grown commercially in a couple of countries. The edible corms are used primarily in Asian food and are prized for their ability to keep a crispy texture despite being cooked or re-heated.
Despite being impossible to grow commercially in the states, it is super easy for you to grow water chestnuts at home. Get yourself a large container, soil mix, a starter corm, and a plan to secure a long growing season. Seven months later you’ll have all the fresh, crispy water chestnuts you can eat!