Grow water chestnuts and other aquatic vegetables

Chinese water chestnuts (Eleocharis dulcis) are a perennial vegetable that are incredibly simple to grow.  I wrote a post about growing water chestnuts in a bucket.  It is simple and the yield was exceptional.  Each bucket often gives me a dozen or so edible size corms, and well over a hundred smaller ones to replant.  You could eat the small ones, but I find them too fiddly to peel.  

I grow duck potatoes (Sagittaria sp) in the same way.  They are just as simple to grow, and while the yield was nowhere near as large as water chestnuts the duck potatoes also give a great yield for a small amount of space.  

I am told duck potatoes are better suited to cooler climates than water chestnuts, but I find they both perform much the same even in the Canberra region.  Chinese water chestnuts are dormant over winter, so are not impacted by frosts.  I tend to leave some in the soil and as long as it doesn't freeze solid some always survive to grow the following season.  Below are photos of plants in my greenhouse where they are protected from frosts, until this year I have only grown them outside next to the fence where the water is covered in ice regularly over winter.

To grow them I would fill a bucket a bit over 3/4 full with soil and leaf litter.  Plant a water chestnut into this.  Then add water until it over-flowed.  I would put this in the sun, top up the water as needed, and harvest in autumn after the foliage died off.  Gardening really doesn't get much easier than this.  

The buckets would last about 4 years before they would start to fall apart.  Some lasted a lot longer, I still have some that have not yet fallen apart.  

Recently I started to wonder why some buckets degraded at 4 years, and others are still going after ten years.  I think the bucket degrades slightly from the sunlight and becomes brittle, but is able to stay together because there is no stress placed on the sides.  When I harvest I think I must put too much pressure on the bucket and it falls apart.  The ones that have not fallen apart are the ones I have been very careful of when harvesting.  

These buckets are very cheap (less than $1 each), so this isn't about money, I don't want to be wasting plastic if I can help it.  

This year I am trying something a bit different.  I am submerging a pot of soil in the bucket of water.  Come harvest time I can lift the pot out, harvest what I want, and return the pot, all without stressing the bucket.  I think it should work, and it should make harvest easier for me.  

Below are photos of what I am trying.  

I got a cheap 10 liter bucket, and a slightly smaller pot.  The bucket is the cheapest I can find, the pot was given to me second hand.  I already have water chestnut corms, and I use soil that I dug out of the drain in front of my garage, so it is not a huge financial expense.  

10 L bucket and the pot

I filled the pot with soil and leaf litter from a drain in front of my garage.  I didn't fill the pot the whole way, simply because I didn't have enough soil.  It would probably be better if it was filled higher.  These plants need soil if they are to return a decent crop.  

Had I thought about this earlier I would have done this a few months ago and added manure from the chicken house.  Poultry manure is great for the garden as it contains all essential nutrients for plants growth, but it can't be used fresh.  If I tried this now it would burn my plants as it would not have time to 'age' enough.  

Fill the pot with soil

I put some water in the bucket, and submerged the pot.  From here I will plant a water chestnut, or a duck potato, and top up the water.  

In autumn or early winter I will lift the pot out of the bucket, and tip out the soil for harvest.  This sounds much faster and easier than harvesting by digging through frigid water and mud in search of corms with my cold hands. 

Pot of soil submerged in bucket

In this bucket I planted one water chestnut in the soil.  The water level was slightly too high, so I lowered the water level so a leaf could emerge into the air.  

Chinese water chestnuts and duck potatoes both need their leaves in the air, otherwise they may rot.  For now the plant is still tiny and using its leaf as a little snorkel.  Once the plant grows taller I will increase the water level to the top of the bucket.  

  

Water chestnut planted

I tend to grow azolla on top of the water in buckets like this.  Azolla sequesters nitrogen from the atmosphere, and acts as a high nitrogen fertiliser when it dies.  I normally let the water level drop to the soil level every week so ants can carry off all the mosquito larvae.  Placing a pot in a bucket like this will make that impossible as there will always be free water in the bucket.  Azolla is also proven to reduce the number of mosquito larvae surviving to adulthood, so hopefully it helps.  

Water chestnuts ready to grow 

I put a few pots in buckets.  The plants will survive, and divide, and provide an edible crop, so even if this method proves inefficient I won't have lost anything.  

I have high hopes for growing them in a pot submerged in a bucket this, but I am also starting to wonder if I will have mosquito issues doing things this way... perhaps I should put fish in one bucket and no fish in another and see if what works better.  

Keep an eye on my blog as I plan to update how having a pot in a bucket works (or doesn't work) for growing water chestnuts and duck potatoes.  

If you want to grow water chestnuts in a bucket, it is far easier than you may think.  The most difficult part is being able to buy the plants.  I have a for sale page where I sell water chestnuts and duck potatoes and other perennial vegetables in Australia.  I update the page regularly, and it has my email address that you can use to contact me.