How to grow Water Chestnut in Australia
Chinese water chestnut (Eleocharis dulcis) is a grass-like sedge with hollow, tubular green stems that grows in shallow water. Under the mud it forms small, dark brown corms that are sweet and crunchy, and stay crisp even when cooked. It needs a long, warm, frost-free season in standing water, so most home growers use a sealed tub or an old bath.
📖 Our full guide: How to Grow Water Chestnut in Australia
At a glance
When to sow by region
| Region | When to sow | Regional note |
|---|---|---|
| South East Queensland | October to January | |
| Northern Rivers NSW | October to January | |
| Sydney & Coastal NSW | November to January | Marginal. Needs warm standing water. Western Sydney possible. |
| Melbourne & Victoria | Not suited | Not viable. Needs warm standing water and long frost-free season. |
| Adelaide & SA | Not suited | Not viable. Needs warm standing water. |
| Perth & WA | October and November | Plant corms Oct to Nov in a tub or old bath of mud in full sun. The frost free plain gives the 7 months it needs; drain and harvest in winter. |
| Tasmania | Not suited | Unsuitable. Needs warm standing water for a long season. Not viable in Tasmania. |
| Canberra & ACT | Not suited | Not viable. Needs warm standing water and long frost-free season. |
| North Queensland | September to February | Extended warm season. Excellent in wet conditions. |
| Darwin & Top End | September to March | Extended season. Wet-season growing ideal. |
Where to plant
Water chestnuts need full sun, warmth and water standing above the soil for most of the season. A sealed container at least 50 cm wide and deep, such as a large tub, a wading pool or an old bathtub, works well, or a pond edge or a flooded bed. They need about seven months of frost-free growth.
They are native to Asia, tropical Africa and northern Australia and grow best in the tropics and subtropics.
- North Queensland and Darwin: plant from September to February or March; wet season growing is ideal.
- South East Queensland and the Northern Rivers: plant from October to January.
- Sydney: marginal; plant from November to January in a warm, sunny spot. Western Sydney is more reliable.
- Perth: plant in October and November in a tub or bath of mud in full sun. The frost-free plain gives the seven months it needs.
- Melbourne, Adelaide, Hobart and Canberra: not suited, as the warm season is too short.
How to set up a water chestnut tub
- Use a sealed container with no drainage holes, at least 50 cm wide and deep.
- Fill the bottom 20 cm or so with a rich mix of good soil or potting mix and well-rotted manure or compost.
- Plant corms bought for planting about 5 cm deep and about 30 cm apart, or start them first in pots of moist mix.
- Keep the mix wet. Once the shoots are about 10 cm tall, flood the container so there is about 5 to 10 cm of water above the soil, with the shoot tips above the water.
- Top up the water through the season so it never drops below the soil surface.
Watering and feeding
Keep water standing over the soil for the whole growing season. Top it up in hot weather. Mosquitoes may breed in still water, so a few small native fish or regular topping up helps.
Feed lightly with a slow-release or organic fertiliser pressed into the mud at planting and again in mid summer. Do not overfeed, as nutrients in the water encourage algae.
Pruning and care through the year
- Stems grow up to about 1.5 m tall; stake or shelter the tub in very windy spots.
- In late autumn, as the stems yellow, stop topping up the water and let the container drain or dry out for about a month before harvest. The corms mature and colour as the tops die back.
Harvesting
Harvest about six to eight months after planting, once the stems have died back and the corms have turned dark brown. Tip out the container or dig through the mud by hand and collect the corms. One corm can produce many new ones.
Wash and dry them. Unpeeled corms keep for a week or two in the fridge, or longer stored cool in damp sand or left in the drained mud over winter. Peeled corms can be frozen. Keep some firm corms to replant in spring.
Growing in pots
Water chestnuts are almost always grown in containers at home. A sealed tub at least 50 cm wide and deep, kept flooded, is ideal. Larger containers hold their water and warmth better.
Using it
Scrub and peel the brown skin with a small knife. Fresh water chestnuts are sweet, crisp and juicy, far better than tinned. Slice them into stir-fries, dumplings, san choy bow and salads; they stay crunchy when cooked. Cooking them is the safest way to eat them.
Varieties
- Eleocharis dulcis
Companion planting
Water chestnuts share a wet garden or pond edge with other plants that love warm, waterlogged soil.
Good companions
Pests and diseases
Water chestnuts have few pests. Keep the water topped up and the tub in full sun.
Pests to watch for
- Aphids Small insects clustered on the stems in warm weather. Hose them off.
Water Chestnut is rarely troubled by disease.
Common questions
How do I grow water chestnuts at home?
Plant corms about 5 cm deep in a sealed tub of rich mix in spring, keep it wet, and once shoots are about 10 cm tall flood it with 5 to 10 cm of water. Keep the water topped up in full sun, then let it dry out in late autumn and harvest when the tops have died back.
When are water chestnuts ready to harvest?
About six to eight months after planting, when the stems have died back and the corms are dark brown. Drain the container about a month before harvest.
Can I grow water chestnuts in Sydney?
It is marginal. They need a long, warm, frost-free season in standing water. Western Sydney is more reliable than cooler spots. They grow best in Queensland, the Northern Rivers and the tropics.
Are water chestnuts a nut?
No. They are the corms of a sedge that grows in shallow water. They are also unrelated to the water caltrop, another plant sometimes called water chestnut.
Can I eat water chestnuts raw?
They are often eaten raw in Asian cooking once peeled, but corms grown in water can carry contamination from that water. Scrub and peel them well, and cooking them is the safest choice.
How many water chestnuts does one corm produce?
One corm can produce many new corms over a season in a well-fed, flooded container.
Sources we checked: Yates: How to grow water chestnuts; Wikipedia: Eleocharis dulcis.