Harvest: Chinese Water Chestnuts & Arrowhead

The first thing I did in my gardening day on Sunday was to deal with the Chinese Water Chestnuts (Eleocharis dulcis) and Arrowhead (aka Duck potato - Sagittaria sagittifolia) which I planted out into my small water bowl last August. As you can see, the foliage of both had all but died off and although I was supposed to be keeping the soil dry(ish) while the foliage died off, the recent rain meant the bowl kept filling up again with water and I was worried that they were rotting.

That's the arrowhead at the front of the bowl and the water chestnuts at the back.

I tipped out the bowl into the garden (upside down) and squelched through the mud with my fingers, feeling for corms. Firstly I started finding the water chestnuts. I was hoping for a much better harvest than last year, when all I managed was 280 grams worth of chestnuts (or about two meals worth). With some advice from Naturewitch, I decided that I hadn't fertilised them enough, so this time I planted out six of the largest corms from my previous harvest, into heavily manured soil, and fertilised them regularly throughout the growing season with a complete liquid fertiliser.

The Chinese Water Chestnuts after rinsing in the outdoor sink: all 285g of them.

So, I was quite disappointed to find that while I seemed to have more water chestnuts overall this year, they are all very small. In fact, I think I ended up with 285 grams - the same as last year!

Each corm is supposedly able to produce up to 100 corms in a growing season, under ideal conditions of course. Perhaps they didn't like the small space in the bowl? The weather? We had several very hot, dry spells when the bowl dried out during the day before I had a chance to top it up... Hmmmm.

I'll definitely plant them again next spring, primarily because I have the water bowl which I'm not using for anything else, but perhaps I'll only plant one or two corms this time?

Next up was the Arrowhead, or Duck Potatoes. This the first time I've grown them, but they never seemed to do very well. They can grow up to 45cm tall I gather, but mine always stayed very small. Again, I wonder if the very hot spells didn't do them any favours?

Anyway, I wasn't surprised to find that the bulbs I could find, were all very small and stunted - certainly not worth eating! Or even saving to replant in spring? I think they might shrivel up too much before then and may not be viable.

Each bulblet is only a few mm across; mature duck potatoes are several cm across.

So! Not such a successful harvest, but then, it is all good gardening experience :-) Next spring I'll try fewer corms, more solid fertiliser, and more water!