When taro’s leaves turn dark brown or die, it could be the time to harvest them, but it also needs at least six months for taro to reach their harvesting root sizes. I remember when the first frost arrived in the early winter, leaves of my two taro plants turned yellow then brown and fell off, although the plants were still alive. The other taro plants at other warmer locations had no problem. Their leaves were still green, but their growth seemed halting.
I should have planted them in spring, but I missed that opportunity in spring. I planted them at the end of July. Therefore, their harvest time would probably be at the end of the next February. However, in early March, their leaves had been still green, so I had to give them more time to develop their roots. In May and June, I harvested some of them by wetting their feet first then digging them out. I did the job carefully to avoid damaging their roots.