We have a small homestead in the mountains of Jawa Island Indonesia and we have tried growing potatoes without much success so far I have narrowed it down to 3 problems 1. Not enough sun(I fixed that) 2.Using determinate potatoes in a barrel setup(Looking for other types) 3. Fertilizer, well we tried just mixing some normal soil with cocopeat and goat poo but it is still not giving good results.
So my question is this:
How do I make the best fertilizer from what we can find on our homestead and how to apply it best?
We have goat poo, rabbit poo, ashes from wood stove, human pee, coco peat, rice husks. We do have some worm castings on top of our grow beds that we usually collect to make a general liquid fertilizer.
In my own experience of growing potatoes in the tropics, I find that they do not like fresh manure. My best results have been when I dug in aged compost. I lightly mulched the top of the soil until the sprouts grew about 6 inches tall, then I added more mulch. This helped keep the soil moist and cool. When I didn't use mulch, the potatoes were smaller and fewer. Potatoes seem to be heavy feeders, because mine always do better when I've dug in plenty of compost. Less compost = less potatoes.
I've had success growing potatoes in a container on my farm where the temperatures are cooler than at my seed farm. The seed farm location is much warmer and drier, and the potatoes there do not do well. I'm not sure if it is the heat it the drier conditions that causes them to grow poorly.
Some varieties do better in the tropics than others. So try several different ones to find the better ones for your location.
It's never too late to start! I retired to homestead on the slopes of Mauna Loa, an active volcano. I relate snippets of my endeavor on my blog : www.kaufarmer.blogspot.com
Too much nitrogen isn't good for potatoes. If using manure, as Su said above, it needs to be WELL composted. Drainage is important -- sandy soil. Also, making sure you have a potato that does well in your area is important. If you can find someone who grows them successfully, get your seed potatoes from them.
"The rule of no realm is mine. But all worthy things that are in peril as the world now stands, these are my care. And for my part, I shall not wholly fail in my task if anything that passes through this night can still grow fairer or bear fruit and flower again in days to come. For I too am a steward. Did you not know?" Gandolf