Next to trees, I have an affinity for tubers - even more than creepers. Rationally, they are easy to grow, easy to store, high in nutrition, long term crops that fetch a decent price in the market. The only input necessary is a bit of moisture. It takes some digging to get them but this being a once-in-a-year activity, I can not complain.  

Harvesting:
Most of these tubers take 10 months to mature and let us know the right time to harvest by their wilted leaves. 30 days from wilting is usually a good time to dig up. 

It was a challenge to locate the yams since we were a bit late and the trails left by wilted leaves had disappeared. Quite a few came out with some bruise or the other. No two yams looked alike! Many of them had a resemblance to UFOs though.

For turmeric, a week before digging, the leaves are cut and stored away to use as fuel.  A narrow and long bladed hoe is used very carefully to unearth the bunch. The turmeric bunch is left to dry off for a day on the field itself. Then the mud clinging to the bunches is dusted off and rhizomes (round, hard mother seeds) are separated from the tubers (fingerlings). Then these two heaps are stored separately.

According to Dhabolkar, every sq.ft of soil can optimally produce 2 kgs of tubers. May be 20% of the harvest met that mark and the rest were at half that mark.

Storage:
Tubers are usually stored in a dry cool place. Large tubers like Yam are placed upside down in stacks on a wooden shelf so if sprouting happens during storage, the sprout is not exposed to light. It's good if the storage shelf has a roof above to prevent direct sun light. Turmeric et al are stored in a heap on high ground on the field. It is better to spread a thick layer of sand or grass at the very bottom. The top of the heap is covered with grass or their own wilted leaves or large leaves like those of coconut or palm.

Sowing:
The ideal season for sowing in our region is Mid-May and hence the ideal season for harvest is around March. But then, tubers can lie dormant in the ground until the time is right for them to sprout.

So we took some harvested yam, cut it so each part has a bit of the sprout and sowed these pieces back in the same deep holes from which they were dug out. This eliminated all the labour associated with planting cycle.

We've also re-sown turmeric well ahead of its ideal season. We broadcast mixed seeds of mustard, castor and sun hemp and as deep dents for turmeric seeds were made with a hoe, these got automatically mixed well into the soil.  First we sowed all rhizomes since these grow with more vigour. When we ran out, we dug into the heap of large fingerlings (Virali Manjal in Tamil). The live mulch will hopefullt limit the weeds while turmeric waits for 25 days to sprout. The young plant likes to be shade for the first 70 days after which the live mulch will be cut and added back to the soil.

One can debate the merits and de-merits of such non-crop-rotation but given the diversity that surrounds the tubers, the 'same place, same time, next year' approach seems to work for now. Next year's harvest will be a good test for these theories.

 Along with turmeric and yam, we've added Ginger and Taro root (Sembu or Seppan Kizhangu in Tamil) to our Tuber Portfolio this year.

Dealing with the Output:
This was our first harvest of yams so we felt like gifting a large part of it to strangers and not-so-strangers. The feedback has been uniformly yammy!

We sowed around 100 kgs of turmeric and harvested around 800 kgs of which 400 kgs were used up as seeds for the next crop. Our graceful neighbour put in a lot of sweat and helped us process the rest. These 400 kgs will shrink to 60 - 80 kgs after boiling and drying depending on how long it is dried for.
 
Haven't made up our minds about what to do with dried turmeric. The common choice is to hoard and sell when the price goes up during monsoon. The second option is to do value addition (polishing to remove the skin, powdering etc) and sell to an organic whole saler when we find one. The third option is to make turmeric powder on demand for friends and family and who ever else is interested in organic turmeric. I favour Option 3 though it looks like a lot of work. Being 2nd generation organic, the turmeric won't go bad for upto 8 years (or so they say). So we have plenty of time to decide!

Oh, and one more thing. I did a late sowing of potatoes also last year and what was harvested is smaller than this font size :)