I'm working on planning and designing my permaculture food forest out here in my semi-arid, challenging corner of the tropics (Haiti).
Many fruittrees have gone in already, and I'm working on the support species (wrong order, I know, but that's how it worked out).
I have one swale in the works and another soon to follow. These will hopefully, be planted with a combination of low growing edibles such as ground cherries around larger trees and some smaller trees like acerola cherries and pomegranate.
But I'm somewhat stuck on this part of the plan. What are good options in the "berry" department for the tropics? I have a mulberry and will get some more, but they aren't exactly what I think of as shrubby berries.
I have a grape vine I'm planting today too, I think. But that's not really suitable for an understory layer, since it needs more sun.
Natal Plum, Feijoa (pineapple Guava), Dragon Fruit Cactus, Pomegranate, Edible Canna, Taro, Chaya, small Citrus trees, Prickly Pear Cactus, Chili Pequin (Bird Pepper), Fig (pruned small)
If I were growing in the tropics, I would try a lot of things from this website: http://www.tradewindsfruit.com/tropical-fruit/ I'm currently growing Edible Canna from seed I bought from them. Unfortunately Canna like a lot of water, so I'm growing mine in a tub, not in the ground. Same with Taro, but that has to be grown from a tuber. I bought mine at a market in the city.
Dry conditions really limit what we can grow. If I remember right, you said you don't want to irrigate. Natal Plum, Feijoa, Prickly Pear, Pomegranate, Bird Pepper, Fig, and Citrus can grow with very little water once well-established, but might not produce much fruit, because fruit is mostly water. My Prickly Pear don't even like to grow new pads (which are edible) unless they get some water or decent rains.
I've got a native prickly pear that is currently growing in a pot. I have several dragon fruit, and we also have another edible cactus variety that grows naturally in the native trees.
I am trying to get a fig to root, with little success. I have a pomegranate in the ground currently, and hope to get more. I have one of 4 cannas that has survived that I'm trying to coax into giving some real growth (started from seed). I have 4 pineapples that seem to be doing ok, especially since it's rainy now. We'll see how they do when. It's more dry. I also have some herbs and such.
It's not so much that I don't want to irrigate, but I don't yet have that option. I'm working on a rain water collection system, but barrels are expensive here (everything that is imported is expensive) and we are on an extremely tight budget. We're also looking into graywater for irrigation, but much of my grow space is uphill from where the output is on the plumbing, so that limits me a bit too (electricity is inconsistent at best).
Currently my irrigation system is with 2 and 5-gallon jugs with a hole poked into the bottom for slow drainage. That works for individual trees, but is somewhat labor intensive. So I'm really looking towards deep mulch and organic mass and stuff that can handle it.
We are in an Mediterranean climate that is semi-arid (fast becoming arid) and Cape gooseberries (phsyallis) works really well as a intermediate layer. In just 3 years, I've been able to breed seed that needs no water by starting with 10 plants in a harsh environment, and then just planting seeds from that area where I did no watering (two plants survived well enough to give fruit). Blackberries also pretty hardy. But I feel like if you keep asking around, you might learn a lot more about what others grow locally.
Amaranth is very hardy and grows quite tall-- but even with no water can survive.
If coffee a possibility? I'm growing robusta, as arabica doesn't do well close to the ocean-- but if you're in hills coffee might be good if you have some shade? Our robusta is surprisingly ...robust and resilient.
Natal plum can be a little picky about conditions, and is very slow growing. Kei apple is a good option if you're looking for security, but the thorns are massive so keeping on the exterior of the planting space probably good. It's also very hardy and a great windbreak.
We also put large-ish medicinals like wormwood and pelagoniums.
All the different passiflora can survive with very little water once they're established (ie. if you can grow until quite large in a pot, then transplant...)
Roselle hibiscus? Here hibiscus is very hardy.
But I wish I'd asked around earlier when we were setting up our food forest, and not been as tied to specific permaculture plants, as I think I had a lot to learn just from what people put around and about.
sortof-almost-off-grid in South Africa: www.concretegardener.com
People don't grow much of anything here. Where there is anything growing, it's primarily veggies or papaya for market. Goats and charcoal are the big industries of our area, and they are both super destructive. Property lines are a mere suggestion at best. We have another house being built on university property without authorization. That's the third since the university was established 6 years ago. Ha.
I do have Roselle growing and it seems to do well, though some have mysteriously died. I'll have to try some experiments. I can try some passion fruit under some of the larger trees as support. I know others who have grown them successfully not too far from here.
We do have some local medicinals that I'm researching as well.
You mentioned blackberry. Are they hardy in tropical regions? I've never heard of them being grown here.
I have Amaranth seeds on their way. Also ground cherries.
Our elevation is too low for coffee, I believe. That's what they tell me anyhow.
Where would you suggest finding seeds for kei apple and cape gooseberries? Those sound hopeful . . .
Thanks for your reply. I'm always in awe of the seeds that one can get in the U.S., so if you have access to that market I think you'll be able to access the seeds really well:
Dovyalis caffra (kei apple) grows readily from seed.
Cape Gooseberry-- has a version called uchaya that grows really large in South America-- I think the seed name to search for would be Physalis peruviana, and it grows really well from seed.
For coffee, your elevation is too low for arabica but you can grow robusta. We're at sea level and grow relatively well. Robusta grows really well in Vietnam, also at sea level. So I think it's something to consider. Growing from seed is also feasible, but coffee seed needs to be fresh to grow.
Would pigeon pea be a good crop? or other types of drought resistant peas would be potential amazing.
Groundnuts (close relative of peanuts) are sometimes drought resistant.
Tagasaste/siberian tree shrub also seems quite good, and if you're looking for examples of what might work as goat feed?
Can you get/make plentiful biochar? We managed to connect with a local charcoal production company where they're almost giving away the small pieces, which are produced in just the right conditions to become biochar once they're mixed with compost/innoculated. I've been really grateful for this new byproduct in my area.
sortof-almost-off-grid in South Africa: www.concretegardener.com