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Author Topic: Potatoes: My experiences with Plectranthus rotundifolius and Dioscorea bulbifera  (Read 1632 times)

Caesar

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Hi all, I'm writing up this thread to update y'all on the story so far with my non-solanaceous potatoes. First, the Potato Mint (P. rotundifolius):

The plant was vigorous almost from the start. It arrived early in the year as a tall and kinda weak-looking fully-rooted cutting from a Florida eBay vendor, and I planted it in one of those big plastic tubs with holes drilled in the bottom. I also planted a Guinea Yam (Dioscorea rotundata) in the same tub.

A week after planting and the potato mint already had plenty of strong growth. A month after planting, and it had already taken over the entire tub's surface area with foliage, and some branches were bending toward the soil and taking root. A few weeks later, and it was spilling out of the tub and onto the surrounding ground, so I decided to give it a drastic pruning, leaving behind a few stumps... In hindsight, that was probably a poor decision as the growth of new foliage would probably take vital energy and nutrients away from tuber growth. Lesson learned. I threw some tomato seeds onto the newly-exposed soil surface and forgot about them.

A few weeks afterwards, and the growth was carpeting the tub again, and the pruned stems I had thrown on the ground had taken root and started growing on their own (I left them there and they keep growing to this day). The surviving tomato plants grew tall between the potatoes, and soon both species started flowering simultaneously. A few weeks afterwards, with the tomatoes producing and the potatoes' flower spikes starting to fade (which means harvest time), I pulled up one of the potato plants and dug up the tubers.

Given the various less-than-ideal circumstances (container-growing, competing plants, partial shade, no fertilizer, impromptu heavy-pruning) the crop was small (and composed of mainly smaller tubers), but I'm confident it would've been a good crop under better circumstances. The biggest (normal-sized?) ones were about the size of a small potato, but many were smaller (like Lerén tubers), and a score of them were tiny (these I saved for re-planting). Even with a suspected smaller crop, I actually got enough potatoes out of that one mistreated plant to have a full plate of mashed potatoes. I pulled the remaining plants out the next week and had them fried.

The tubers were amazingly easy to process, so that even pinky-sized tubers were quickly dealt with and used. I put on a pair of gloves, and scratched the skin off under running water quickly during washing off the dirt. In fact, while the nails may have slightly sped up the process, it probably wasn't necessary, as the skin rubbed off with the soft part of the fingertips, it was that tender!

The tubers were white, but many had large areas of green under the skin, and a few had purple areas (all from the same plant). I was unconcerned with toxicity as I'm pretty sure the entire plant is technically edible and non-toxic. After boiling like normal potatoes, I tasted a few whole and mashed the rest. The taste was really very close to true potatoes, with a slight vegetal tone my family likened to Artocarpus camansi seeds (the very mild, immature ones, not the strongly-flavored ripe ones), but milder still. No purple remained after boiling and there was no bitterness or any discernible difference between the green and white areas. I should also point out that some sources mention a sweetness to the taste... I detected no such sweetness (nor any minty/peppery/spicy taste), it was just potatoey.

The second batch of tubers was prepared for frying. Some were left skin-on (I recommend it, though it requires delicate washing), many were sliced lengthwise, a few sliced into chip shape, and a few smaller ones were fried intact. Crispy outside, soft inside (even the chips were a bit flexible), and the flavor was like a combination of homemade french fries and fried eggplant (the good types; no bitterness). They were very good, and doubtless would've been excellent seasoned and roasted like wedge potatoes.

The verdict: unknown prospects as a commercial root crop (especially given how easily the skin rubs off), but excellent for the home vegetable plot. Vigorous and nearly care-free, probably productive (especially with good care and space, not like my neglect), easily propagated, easily processed, and of good taste. I highly recommend it for any warm-weather vegetable garden (no idea if it has a short enough growing season for cooler regions).

***

Now the Edible Air Potato (D. bulbifera):

I received 7 bulbils through the combined efforts of Chandramohan and Roy. They were quick to sprout through the dirt, the last of them a few weeks after planting. Each bulbil sprouted several vines, and would continue sprouting more throughout the growing season. Alas, my crime of neglect was worse with these, and I'm probably not witnessing full production (even though it still seems like a vigorous producer). For my current lack of space, I transplanted every single one of those plants (together with a Chinese Yam, D. polystachya) into a single tub that was probably only big enough (but not ideal) for just two plants; one trellis shared between them.

Despite the circumstances, they also grew vigorously (and twined together), and all seven plants are alive and well. Months passed without a single bulbil (it's not supposed to bear until close to the end of the growing season anyway). Then one day I saw a small bulbil, and it remained alone, increasing in size until almost reaching its maximum (small potato, but bigger than the P. Mint) long before any other bulbils showed up. When others showed up, it was an almost explosive profusion of bulbils, with a rough count of approximately 47 (which I'm fairly sure fell short of the true number even then; by now, many more still have showed up).

All was well and good, to a point, but there's an important thing to mention about this plant: it seems far more susceptible to animal pests than any other yam I've grown. Nothing of note has ever touched any of my other yam vines. Meanwhile, I've seen bulbifera leaves eaten by crickets, cockroaches and snails (and possibly a grasshopper and a katydid, but I didn't see them chewing). And the worst part: the snails ruin the bulbils themselves! I saw one with a gaping hole that looked like a bird pecked into it, thinking it was a fruit. For a while, that's exactly what I thought. But one night I decided to check on the plants at midnight and I started seeing the different pests in action. A week later, I saw the snail on the bulbil, and a second one on another one, rasping holes right through them. Suffice it to say that I've been hunting snails often since then, and crushing every one I find. But the damage was done: in a blind panic, I harvested the big one for fear that a snail would get to it first.

Strictly speaking, I'm not certain that you're not supposed to harvest them, but I was under the impression that you're meant to leave them on the plant until they drop off naturally. A friend (who has harvested alata bulbils) told me that if you pick them before their time, the flesh would be green, and they'd be inedible. Well wouldn't you know, when I went to cook the big one, it was green all the way through. Peeled so that I couldn't plant it, and seemingly too green to be edible, I had to throw it out. Crushing disappointment after all that waiting. Oh well, I've waited this long, I can wait longer for the other bulbils to ripen. I plucked a few small ones from a drying vine to propagate them, but the few big ones I've seen look like they have a few months to go before they drop. I'm hoping the little ones grow quickly, so I can get a half decent crop when it's time to taste them. I truly have high hopes for this plant, and will give my usual play-by-play analysis when I taste them (probably some time next year).

***

Photo Gallery:

The African Potato / Potato Mint:




Same, boiled, mashed and fried:




The Air Potato:




Snail damage:




The big one:


stuartdaly88

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Thank you so much for the post!!
Very interesting and Im glad to find out that one of the so called African potatoes are tasty! Now I just eed to get myself one :)
Waiting for your report on air Yam :)
Patience is bitter, but its fruit is sweet.
-Jean-Jacques Rousseau

Chandramohan

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Caesar, You can still eat the bulbil even if it is green inside, only it will be crunchy and not soft like a boiled potatoe. If you have many vines, you can dig up one of the tubers and eat it after boiling. It tastes better than the bulbils!!!
« Last Edit: December 06, 2017, 05:58:22 AM by Chandramohan »

Caesar

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I was thoroughly disappointed in myself on reading that I could have eaten that first bulbil. Oh well, lesson learned. I did get to try a bulbil in late december. And I tasted the roots in late February/early March. Both were boiled as one would boil other yams: until softened (no exceptionally long period for "toxins" or anything like that). But in waiting so long to write back, some minor nuances in flavor are lost to me, so my apologies in that regard. What I do remember is this: the bulbils and the roots are actually very similar to one another in taste; the bulbils were greenish even when ripe, and the roots were light yellow. There is a definite potato element in the flavor that is absent in other yams, and distinct from the potato flavor found in Plectranthus. Also, a very mild note (stronger in the bulbil) that reminded of bitterness, but nothing like the real bitterness one finds in nasty yams. The texture was firm when in chunks, and dense and pasty when mashed (not dry/floury like some of the better D. rotundata nor mushy like some D. alata). Some of my family members reported a slight slimy texture, which I didn't find (the closest I found was an oddly firm & slightly slippery texture in one tiny chunk, possibly near the stem end).

My personal verdict: agreeable flavor, but not top quality. Still, much better than the mediocre yams I've had, and even without the bulbil gimmick, I'd consider it worth growing on flavor alone. No strong bitterness, no rough fibers, no weird textures (at least, not that I could taste). I got to harvest and taste my D. trifida on the same day, and the D. rotundata a few days later; both of them turned out exceptional, so my palate was probably spoiled for them.  ;)

***

A gallery of the harvests (and some cooking pics):

The bulbils. I cooked one, and planted the rest. Notice the dark-ish color of the cooked flesh, and the even darker water it leaves behind. Not quite as dark as some of the bitter yams I've had (the "mediocre" ones I keep referencing: particularly poor specimens of D. alata and D. rotundata), and without their bitterness.




Some bulbifera roots (which should grow bigger with each passing year) and the normal-sized trifida roots (broken off from one cluster). Notice the paler color of the roots (though still yellow, in contrast with the white trifida roots).



And finally, a picture of my prize (though small) rotundata:



***

Finally, some extra experiences with the bulbiferas:

Snails and slugs continued to attack some of the remaining bulbils as the season went on, so I'd consider them the number one pest.

The overwhelming majority of the bulbils were very small, and I doubt they'd be worth much effort to prepare to cook. I'm not sure if picking some off (as one does with fruits) would increase the size of the remainder or if that's random. Seeing as production should increase over the years, I'm confident that I'll get a greater proportion of larger bulbils over the years (though I'm not sure if the plant should be covered by them, or anything like that). This was their first year (and crammed together in a single pot on a single trellis), and first year bulbil yams of any kind are supposedly poor producers.

Also... as I noted in the first post, I planted seven bulbils. When I dug up the roots, I found nineteen roots! I don't even know how that happens! While they were mostly clustered, none were connected (unlike the mass of trifida tubers). So not only are they productive in bulbils, they also seem very productive as roots (at least, when sown as a bulbil). I ate several roots with my family, and planted the rest, to hedge my bets in case something goes wrong. So far, none of the bulbils has sprouted, though none seems to have rotted either. Here's hoping I can get a mass of plants to spread around.

And that's it for the preceding season! I'll keep you all posted on any special developments this season.

Chandramohan

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Caesar, I am surprised, I have been growing Dioscorea bulbifera for many years now, and I have only one vine growing from one bulbil and only one root tuber from each vine while you have many of both! Yr soil or climate must be very good for them!!

Caesar

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Caesar, I am surprised, I have been growing Dioscorea bulbifera for many years now, and I have only one vine growing from one bulbil and only one root tuber from each vine while you have many of both! Yr soil or climate must be very good for them!!

Perhaps the climate? I think it's pretty standard tropics over here, but not Ultra-tropical like at the equator. And I grew them where they'd receive direct sun, and kept up a heavy watering regimen during most of their growth. What's the climate and soil like at your place?

I used a seemingly high-quality store-bought soil to fill the tub where they were growing, and I did get to apply fertilizer once or twice. The actual soil on my property - outside the tubs - is a pretty heavy clay. I think it was landfill, to stabilize the area; I live in a hillside suburb. None were grown outside the tub.

The bulbils had already started sprouting when they arrived, so I buried them somewhat deep in their original pots, to let the stems acclimate to the local moisture without having to bag them. Once they burst through the soil, I let them grow a few more weeks before planting them all in the tub. There was only one bulbil per "hatching" pot, and each one had several vines, sometimes up to five. Since they were all doing it, I thought it must have been normal.

I think I forgot to post this initially, but this is the one pic I have of one of the bulbils sprouting through the soil for the first time. Three visible vines at this point.



What's the bulbil production like on your vines? Heavy or light? Have you noticed a difference between yearling vines and older vines? And what's their size range usually like?

Seeing as this is clonal material, I don't quite understand how mine turned out different, but it may very well be environmental, as you said. The multiple in-ground tubers were a surprise that I still haven't gotten over. I've never seen a yam do that, at least not in that way. The D. trifida was a solid cluster where you had to snap off each tuber from a solid top. With the bulbiferas, they were clustered in space, but they were loose. I didn't snap a single one off another when harvesting. The only clustering yam I've heard of that might be similar is D. esculenta, but I haven't acquired that one yet.

Caesar

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Re: Potatoes: P. rotundifolius and D. bulbifera + Lerén & D. trifida
« Reply #6 on: May 29, 2018, 06:16:24 PM »
A new update on my tropical root veggies:

The Potato Mints have started coming up from the seed tubers I planted, and I have spread them about between my grandmother's yard and my vegetable tubs. Many plants, plus a few extra growing strong from accidentally snapping some stems (which grew back from the roots anyway).

I'm concerned that I may have lost my D. polystachya. I have some suspects currently in pots, but they're similar to D. bulbifera when sprouting, so I can't yet be certain that I have any remaining. If I can positively identify any of the bulbils/vines, I will be growing them separately from the other yam vines from now on, in a 5 gallon plastic bucket (to hopefully keep the tubers compact).

From the original D. trifida plant, I now have 8 sprouted tubers, 2 of which have broken the soil surface. 2 of them are planted in one of the big plastic totes with a sprouted D. rotundata and 6 (¿or 7?) D. bulbiferas (some of them sprouted, with many feet of vine growth). The other 6 trifidas are in another tote with 3 Lerén plants and 4 potato mints. The Lerén are growing healthy and strong, and I hope to have some material to share this winter, along with the rest of my roots.

Regarding the D. bulbifera, I was concerned about bulbil viability... I am concerned no longer. Of the 19 roots, 6 (¿7?) are planted in their original tote, 4 in my grandmother's yard. The other 9 (¿8?) were eaten within days of harvesting. I'm unsure of some numbers there because not all have sprouted past soil level and I can't quite remember, but all were viable. Regarding the bulbils... Dear Lord! Of the 80+ bulbils I planted (ranging from medium to tiny), 66 were accounted for as having sprouted, 2 remain unsprouted-but-viable, and a few (uncounted, but I think less than 5) were explicitly found rotting. Any others remain unaccounted for (possibly tiny ones that rotted long ago). Of the 66, 10 were snapped when I tried to separate them from their communal pot, but they snapped off with strong roots, so I'm confident they'll survive. They were replanted alone in the sprouting pot to monitor their progress, and their tubers were planted elsewhere to see if they'd sprout new vines. Of the remaining 56, 10 vines were separated for a local friend, and 1 vine for another. The fate of the remaining 45 vinelets... Well, let's just say I'm repeating the sins of my past. First, a little context:

I'm not kidding when I say I have no available space at the moment. I tend to place new projects on hold, or otherwise execute them in containers, as you see here. Half of my trees are in temporary containers, waiting for their time. The back hillside of my home is prime planting space, but if it was totally inaccessible before (when it was merely covered by an impenetrable jungle of weeds), it's nearly impossible now with the fallen trees from the hurricane (that are themselves overgrown with the worst vining weeds). I'm just one guy, and tackling it by myself in the more manageable early days yielded very little progress (a tenth of the space or less cleared) for several months of effort. And that minor result was undone when I had to recuperate for a few months from minor surgery. Suffice it to say that I am unwilling to tackle it directly myself these days (it's an angry-button issue for me). So how would we handle it at home? Hire someone to clear it. It's pretty common practice over here. But we haven't been able to lately, and even if we could, it's a little harder to find someone with a chainsaw for the trees. So for now, I have no available space.

Back to the bulbils, and with the context of no available space, I planted all 44 remaining vinelets (and the 3 viable bulbils) in a single plastic tote. Extremely oversaturated with plants. I honestly do not expect this to yield good results, above or below ground. Nevertheless, consider it an experiment: Ultra-high Density Planting. If it goes as badly as I expect, you'll have direct evidence, the experimental poster-child of why you shouldn't have too many plants growing in a small space. If it actually goes well (or shows potential for slightly less saturated plantings), then you'll have incentive to try out high-density plantings yourselves. Regardless of the outcome, you can be sure of one thing... Half the folks in the forum are getting bulbils this next season.

*

Photo Gallery:

The Trifida/Lerén tote:


The 9-Yam tote (3 species, ignore the true potatoes I'm sprouting on the surface):


The Ultra-High Density D. bulbifera tote (many are below-soil while acclimating):


pineislander

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Good for you, Caesar! I was able to find D. trifida yams at a local Hispanic grocery (from Costa Rica) and planted them immediately, hope they sprout. I did meet someone with the D. bulbifera here in Florida. The main advantage he explained to me was that you can grow them as a perennial, leaving the root portion permanently in the ground, and just harvest the bulbils. Sfter the first season the in-ground tubers become very vigorous and produce large numbers and large size bulbils. It seems that other yams including alata do the same as far as bulbils are concerned. Last year I got no pruple Ube alata yam bbulbls and di harvest all but this year I may save 1/2 my crop in-ground to attempt looking for the 2nd year bulbil crop. My ordinary alata bulbils did grow out very well last year so what I am seeing is that it makes sense to keep a "mother" yam going which might make multiple bulbils each year to use as planting material.

here is an example of a central Florida purple alata yam in it's second year and resulting bulbil crop:
https://www.youtube.com/watch?v=QGIByH-lpzU&t=5s

Caesar

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Excellent! Those trifidas should grow well for you. My original stock was from Walmart (Costa Rica as well, I think), and they had a slight sweetness to the taste that was absent from my own harvest (either way, it was a great yam).

Another bulbifera grower? Is he from the forum? Did he mention the type or origin of his stock? I'd like to buy or trade for some of his at his next harvest, if it's different (even better if they're several). The more edible types grown, the better. Las Cañadas in Mexico (link here) has an African type that I'd love to get my hands on (link to their catalog here). Only problem is they don't ship outside of Mexico. If I could get a forum member from there to buy and resell it to me, that'd be great, but I've no idea who to ask about that. With some of the projects I have going on right now, I plan to obtain quite a few more totes to grow some of the stuff I can't put in the ground right now.

That looks incredible! I'm pumped for the purple Ube, can't wait for your harvest. I'll trade you for all my roots. I've also been meaning to grow some white alatas (maybe "Florido"), but I haven't found a satisfactory variety lately, and didn't have the foresight to save the stem-piece from the last good one I ate. As soon as I get a good one, I'll be growing it for bulbils for sure.

pineislander

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The fellow I met this weekend at a permaculture meetup in Florida has the 'angular' type bulbifera as shown here. From your pictures you have the more spherical type. I'll be trying to get some of his bulbils and share when possible.

https://growerjim.blogspot.com/2016/12/dioscorea-bulbifera-edible-air-potato.html

https://www.youtube.com/watch?v=vlSEfpFs0Us

Caesar

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The angular one! I think that's the same African type they grow in Las Cañadas. I noticed he mentioned "Hawaii" as a second cultivar. Does he have it and others, or just the angular "Africa"? I think my round type is "Sativa" since it comes from India, but I don't know if they have other cultivars in India, or if the Hawaiian one is different from mine.

Incidentally, did he happen to mention if he had D. esculenta?

I checked a few of David-the-good's videos and I think he has at least 3 different cultivars growing (2 round ones and maybe the angular one). Wouldn't mind getting in touch with him for a trade. If this keeps up, I may end up making a clonal repository for edible Dioscoreas.  ;D

pineislander

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He does, but I believe he has been growing out of the country for awhile, Hawaii and Central America. So, what he has is probably not coming back into the USA.

 

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