Saturday, 24 May 2014

Chinese water chestnut yield

It is about time to harvest the water chestnuts.  This year I grew them in small 10 litre buckets, it was very cheap, simple and took up very little space.  This method could even be used on a balcony as it is not only productive but if you used nice looking buckets it looks good too.  I have put details of how I grew them here.

The buckets were cheap and easy to find, I filled them with clay and manure from the property, so it was also very cost effective.  They required no weeding, no pruning, no maintenance at all other than the initial planting and then filling up the buckets with water when I was out watering the rest of the vegetables.

water chestnut corms for sale in Australia
Water Chestnuts growing in a bucket
Water Chestnut yield

One bucket was ready so I pulled the plant out and broke open the root ball in search of water chestnut corms.  There were a lot of corms in that bucket ranging from tiny to medium in size, unfortunately none of them were very large.  Most were too small to bother peeling and eating but about a dozen were edible size.  A dozen edible corms return per corm planted is not too bad considering how simple this was.

I ended up with around 127 corms from that first bucket (plus a heap that were too small to bother counting but are probably just as viable), all together they weighed around 365 grams.  That bucket also produced a decent amount of straw which I can use as mulch somewhere in the vegetable garden.

The bucket had a lot of corms squashed against the side as the plant tried to reach new ground, these corms will all grow and are genetically identical to the rest of the corms in the bucket so they can be used to grow next season's crop.  They are not easy to peel as larger and rounder corms so will not be eaten by us.

I am guessing that the other buckets will yield roughly the same in terms of weight.  I have high hopes that one bucket in particular will have less corms, but they will mostly be larger corms.  That bucket was not started off with planting a corm like the others, instead I had a spare bucket of soil so I broke off a runner from one of the other plants and put it in there.  I think that it will have produced less corms and they will all be a bit larger.  When I harvest that bucket if it is any different and I remember I will try to write a comment or another post.

All of those small corms are great as it means I have plenty of stock to plant next year and to feed to animals, but I would prefer to have a lot less corms all of which are much larger. 

Water Chestnut corm

How much did it cost me

Normally I don't do this but I thought I would write the cost of this little water chestnut growing experiment.  One water chestnut corm $2, one bucket $0.85, soil & fertiliser etc $0, water $probably a few cents.  

For a total expenditure of less than $3 I got about a dozen edible sized water chestnuts.  That means each of the larger edible sized water chestnut effectively cost me about $0.24 plus produced some straw and whatever added benefit of having insects and wrens hanging around due to the water.  

Next year I already have corms to plant and the buckets so each water chestnut will essentially cost a fraction of a cent.  I doubt the buckets will last more than a few years due to the sun, but we will see what happens.

Things I plan to do differently

One factor which may have made the corms so small is that we went away towards the end of the growing season and some of the buckets dried out which meant the plants died down early.  Some buckets are still actively growing as they did not dry out as much, so time will tell on this theory.  Perhaps if they had constant water in the late season, like they did throughout the rest of the season, they would have kept growing and the corms would have increased in size.

I think that I can make the plants produce larger corms in a few ways.  Firstly I think adding more manure and having less soil will help.  More manure will mean more fertility, hopefully this fertility will help the plants to produce larger corms. 

I will probably have the soil level slightly lower and the water level slightly higher, this will help prevent drying out on hot days as happened a few times here over summer.  During summer where the daytime temperatures were in the mid 40s for weeks on end meant I would fill the water container in the morning and by the afternoon they had dried out, having lower level of soil will mean that I can have slightly more water in the bucket.  Having a deeper and wider container would help, but that is not really an option right now so I am sticking to growing in buckets.  

Growing by splitting off shoots and planting them part way through the growing season should help to reduce the number of corms in each bucket and hopefully ensure that these corms are larger.  If this does not work I know that there are some improved varieties out there which grow larger corms, but getting my hands on them seems almost impossible.

I plan to grow them again

Overall I am happy with how this turned out, I got a good yield of edible corms from a tiny space with next to no work from me, a massive yield of propagation material (and/or animal feed), and a good amount of straw.  Considering that all this resulted from planting a single corm that was only the size of my thumb nail I count it as a win.  I have a few things to change for next year to hopefully ensure some larger corms.  

They taste nothing like the water chestnuts from a can, they taste a lot nicer.  They kind of taste like something familiar that I can not quite put my finger on, perhaps coconut.  I wish they tasted more like yacon or jicama as some people have suggested that they might, but they don't.

Being a perennial vegetable it means that if I decide that I want to I can continue to grow these for ever.  Considering that the largest cost in growing these is purchasing the corms, and given how simple they were to grow, having my own supply kicking over each year seems to be a sensible option.

Where to buy water chestnut corms in Australia

Like many of the other perennial vegetables I grow I do sell water chestnuts.  The corms that I sell are larger than the ones I initially bought, but they are not as large as they will get if you give them room.  If you are interested the details can be found on my for sale page.

Wednesday, 14 May 2014

Small scale home aquaponics

My fish tank started to get a bit stinky and I don't have a lot of water here so am hesitant to do a water change.  Being outside it gets a few hours sun in the early morning so the sides get covered in algae.  I used to scrape it off on the viewing side from time to time.  I used to leave it on the other three sides so that it helped suck some of the nutrients out of the tank.  I also always try to have duckweed growing on top to help improve water quality.  This works fine as long as some of the water is changed very now and again.

Then I considered turning my fish tank into a mini aquaponics type tank.  I have been interested in aquaponics for some time now.  After a lot of tyre kicking I am ready to give it a go, but we are planning on moving soon so I do not want to start anything too big so this works out well and helped me to learn how to do it properly on a larger scale.

I had a little bit of styrofoam in the yard.  That got me thinking.  I wanted to set up something that would work with my fish tank, something that was simple, something cheap, and hopefully something productive.  The more simple the better.

I bought two tiny bristlenose fish (Ancistrus sp, or as my kids call them "nibble fish") to eat some of the algae, but then I still had a lot of ammonia, nitrites and nitrates to deal with.  Adding extra fish only makes this problem worse.  Duckweed helps, but there are a lot of fish in my tank producing a lot of waste.

I then got a piece of styrofoam, punched a few holes in it, and inserted some herb cuttings which had tiny roots.  Within two weeks the cuttings had long roots, the water no longer smelled bad, the sides had noticeably less algae on them, and the water was a lot clearer.  I had no idea that it was not all that clear before, but the difference is remarkable.  This was fantastic, but I am not sure if this is due to the plants or the new 'nibble fish' or a combination of both, chances are this will only work short term as the plants may rot with the roots being in water all the time and oxygen levels not being high enough.

I then set up a small fish tank at work with a pair of Endler's who began to breed.  I planned on using this to do small scale aquaponics and try to be as productive as possible.  After the fish had been in for a few weeks and increased in number somewhat I removed the filter and started the small scale aquaponics set up with an eye to work out potential problems and see how productive a tiny tank could be.  This tank is far smaller than my tank at home, but this tank has a light on it.

Many aquaponic gardeners start with deep water culture to keep things simple.  The Aztec floating rafts, or "chinampas" was a way to farm using deep water culture on a large scale.  Clearly this approach can and does work, but there are a few things that one has to do right to make it work well and I needed to teach myself what these things were.

The timeline for my tank at work is as follows:
25/03/2014 - the cuttings were set up
28/03/2014 - first set of photos
10/04/2014 - 2nd set of photos
29/04/2014 - 3rd set of photos
12/05/2014 - plants grew far too large and were harvested

First I got some styrofoam, punched a few holes in it and inserted some herb cuttings, just like the tank at home.  I increased the oxygen levels in the tank to help prevent them rotting.  As expected, these grew like crazy.  I then included a pot of gravel with another cutting.  I "seeded" this pot with beneficial bacteria to break down ammonia and nitrites faster.  The herb in this pot also grew like crazy so a few days later I included a second gravel filled pot with a different type of herb.

small scale aquaponics, the fish are in there somewhere too
aquaponics 3 days in

herb cuttings 3 days after planting - note the tiny roots
I had great plans of taking pictures each 2 weeks to show the growth and development of the plants.  I originally planted basil, mint and pineapple sage.

aquaponisc 2 weeks on

root and leaf growth after 2 weeks

plants larger after 2 weeks

2 weeks of growth, all looks good

Then I went on holiday for 2 weeks, upon my return the plants were huge and crowded under the light.  The roots are spread nicely throughout the water giving the fry a place to hide.  I held off doing anything for a while but the plants got too large, so I cut them back pretty hard.  We made mint and basil lemonade with the herbs.

small scale aquaponics
5 weeks of growth, ready for harvest

Classroom aquaponics
The herbs were larger than they look
I have learned a lot from doing this, many things I thought would happen have happened.  It is reassuring to see things growing in ways that I thought they logically should.  It is also nice to be able to work out any problems on a small scale before doing this on a larger scale with edible fish.  Regardless, I now know how to make this work for me simply and cheaply.

I also have started to grow some watercress in one of the pots, hopefully it does well in a floating pot but it is too early to tell yet.  I also have some seeds of kang kong which have just started to germinate, but I think it is a bit cold for them at the moment.