Dragonfruit: how best to support?

[fyliu]

Cutting at the top of the trellis is right. I was just commenting that the trellis need not be so tall.

[KarenRei]

Hmm, been thinking about this - what do you think about:

 * 7 gal plastic pot, full of tons of drainage/air holes (already have such a pot)
 * Heavy sand at the bottom, mix of light gravel, soil, perlite, and vermiculite above it
 * Plant planted off-center
 * At the center of the pot running vertical is a piece of 3" PVC with a 2x2 inside of it, the 2x2 surrounded by sand, PVC capped on the bottom.  PVC extends a couple inches above the soil; it's only there to keep the post dry..  2x2 extends 3 1/2 feet above the soil; combined with the 1 1/2 foot height of the pot, that's five feet of dangle room for the fruiting arms.
 * 2x2 post is guyed at the top to the rim of the pot to help keep it vertical.
 * Plant tied loosely at regular intervals to the post.
 * No additional supports for the plant at the top of the post - it just terminates (are side supports at the top really needed?)
 * No protection for the 2x2 from the rootlets (just hoping that they don't do too much damage... they're not to bad, are they?)

Think that sounds reasonable?

[WhitH]

* No additional supports for the plant at the top of the post - it just terminates (are side supports at the top really needed?)

From what I've seen online, most of the dragonfruit farms in Vietnam and Thailand do not use additional supports at the top. It's just a vertical concrete post with nothing else. Unsupported, the branches do move in the wind a bit...I don't know at what point that becomes a problem in terms of breakage.

[KarenRei]

While Iceland is a windy place, my apartment is not    Thanks for the info!

[Tropicdude]

from the pot, only allow 1-3 main stem/trunks up the support, cut off all others. once it reaches the top, allow them hang over, its this leaning over that will cause it to branch out, the more branching the better ( at the top )  you can cut them back if the get too long and reach the floor.

You can move the branches around a bit so not too many are on top of another, this will prevent injury.

Dragon fruit , once it gets going, is a super fast grower, I have seen them grow an Inch or more a day!

[fyliu]

I'm basically repeating what Tropicdude wrote but... The idea is to concentrate nutrient supply from the soil to very few stems. Let it get to the desired height and then produce fruits from all the horizontal branches.

Since light plays a large part in blooming, too much branch-stacking should be avoided. Experienced Taiwanese growers are very good at pruning where they keep stacking to a minimum and also remove diseased and really old non-fruiting branches.

[simon_grow]

Hey Stressbaby, did you use Cedar, Redwood or Pressure treated wood for your posts that rotted after 4 years?  I believe they use Pressure treated wood at the UC extensions where they hold the Dragonfruit festivals.  I hear conflicting reports whether or not it is safe to use pressure treated wood for supports and also to build raised beds.  There was a speaker on youtube from DaveWilson's Nursery that said they did some experiments and did not detect harmful chemicals in the veggies they grew in the pressure treated raised beds.  I forget exactly how they worded it so don't quote me on this but they pretty much said it was safe to use pressure treated wood.  We do have to remeber that DF has aerial roots that, from what I've read, can absorb nutrients from whatever its attached to but I would assume that veggies grown on the perimeter of a raised bed would also have its roots reaching the treated lumber and possibly absorbing harmful chemicals. 

I spoke with a lady at Home Depot in the lumber department and she said that whether I use Cedar, Redwood or even Pressure treated wood, I would have to re-paint or re-treat the wood after several years anyways.  What if we use Cedar or Redwood(just to be safe) and then spray the Spray Rubber on the bottom of the posts?  That way, the soil moisture will not corrode the wood that is beneath the soil.  It would probably be even better to spray the rubber about a foot above the soil line but just below where the DF attaches to the post.
Simon

[CoPlantNut]

I spoke with a lady at Home Depot in the lumber department and she said that whether I use Cedar, Redwood or even Pressure treated wood, I would have to re-paint or re-treat the wood after several years anyways.  What if we use Cedar or Redwood(just to be safe) and then spray the Spray Rubber on the bottom of the posts?  That way, the soil moisture will not corrode the wood that is beneath the soil.  It would probably be even better to spray the rubber about a foot above the soil line but just below where the DF attaches to the post.
Simon

I tried using the spray rubber as a water-proofing agent on wood in my last basement plant room incarnation; it let enough moisture through to cause rotting of pine boards after 5 years.  On redwood it might be more effective; I wouldn't suggest using cedar as it leaches chemicals that suppress plant growth.

I'd vote for PVC pipe for a rot-free trellis; you can use 1 1/2" PVC for extra strength.  I've had some 1 1/2" PVC holding up a trellis in my yard for 10 years with no problems.  You can even wrap them with sphagnum moss and wrap wire around that if you want to give the plant something to root onto.

   Kevin

[KarenRei]

I'm not sure 1 1/2" PVC could be trusted to hold 200 pounds.  3" probably could.  Also, this isn't in my basement, but takes up a large chunk of my living room    Æsthetics do matter; I go for the "home as a tropical paradise" look (parrot included!).  Hmm, maybe black PVC would be unobtrustive enough.

[CoPlantNut]

I'm not sure 1 1/2" PVC could be trusted to hold 200 pounds.  3" probably could.  Also, this isn't in my basement, but takes up a large chunk of my living room    Æsthetics do matter; I go for the "home as a tropical paradise" look (parrot included!).  Hmm, maybe black PVC would be unobtrustive enough.

1 1/2" PVC can hold me hanging from it- and I'm just over 200 pounds.  It does bend a little over a 4' horizontal span, 5' high.  Wrapping with sphagnum moss or even something like weed barrier fabric would help it look nicer.  The black ABS pipes are not quite as sturdy as PVC, as they are designed for no-pressure sewage situations, where the 1 1/2 inch PVC can still handle 70+ PSI with its thicker walls.  It will take a larger black ABS pipe to hold the same weight as a smaller PVC pipe.

Note: I built an entire 8' x 16' plant growing chamber in my basement out of 1" PVC in the past and was very pleased; it has some disadvantages but it is basically indestructible! 

   Kevin

[fyliu]

Jack Vincent of Oceanside used 2" PVC for his plants before he had to give them away. His 2 plants were over 100lbs each after he cut 200-300lbs off of them.

The 4 foot horizontal PVC of his trellis was bending when I saw it but it was holding.

[stressbaby]

Hey Stressbaby, did you use Cedar, Redwood or Pressure treated wood for your posts that rotted after 4 years?  I believe they use Pressure treated wood at the UC extensions where they hold the Dragonfruit festivals.  I hear conflicting reports whether or not it is safe to use pressure treated wood for supports and also to build raised beds.  There was a speaker on youtube from DaveWilson's Nursery that said they did some experiments and did not detect harmful chemicals in the veggies they grew in the pressure treated raised beds.  I forget exactly how they worded it so don't quote me on this but they pretty much said it was safe to use pressure treated wood.  We do have to remeber that DF has aerial roots that, from what I've read, can absorb nutrients from whatever its attached to but I would assume that veggies grown on the perimeter of a raised bed would also have its roots reaching the treated lumber and possibly absorbing harmful chemicals. 

I spoke with a lady at Home Depot in the lumber department and she said that whether I use Cedar, Redwood or even Pressure treated wood, I would have to re-paint or re-treat the wood after several years anyways.  What if we use Cedar or Redwood(just to be safe) and then spray the Spray Rubber on the bottom of the posts?  That way, the soil moisture will not corrode the wood that is beneath the soil.  It would probably be even better to spray the rubber about a foot above the soil line but just below where the DF attaches to the post.
Simon

Hi Simon,
I did NOT use pressure treated wood.  However, I did fully treat the posts with some sort of sealer.  I apologize, it has been several years and I don't recall what exactly.  In retrospect cedar or redwood would have been better choices. 
The other thing to note is that I read on this forum that dragonfruit aerial roots do not adhere well to pressure treated wood.  I cannot confirm that, but for that reason I have my pressure-treated 6x6 wrapped in burlap now.  The DF have started to make their way up the structure...

[fyliu]

DF aerial roots provides only marginal adherence to rough surfaces. Even Vietnamese farmers with rough concrete posts. have to tie them for stability.
I think its role is for nutrient absorption than for support, unlike ivy or creeping figs.

[KarenRei]

I ended up buying a nice study piece of roughly 1" aluminum pipe (things in are cm here) that's thickwalled so quite study, somewhat shiny to reflect light but not enough to be disruptive (and it's diffuse), and in general looks nice.  Should be no rot/rust issues.  Obviously the plant has no hope of clinging to it, but that's what tying is for.  Assuming I can get something to tie with to cling to it, lol - may need to drill a few holes.

[jcaldeira]

How many pitaya plants share one vertical support?   When I Googled "pitaya farm" images, some of the photos showed between 3 and 6 vertical stems going up a single post.  Are these all from one plant, or separate plants?

http://www.google.com.fj/search?q=pitaya+farm&hl=en&gbv=2&tbs=isz:lt,islt:qsvga&tbm=isch&source=lnt&sa=X&ei=egDdT4mxH6WX6AHlvJyqCw&ved=0CCoQpwUoBA&biw=1366&bih=599&bav=on.2,or.r_gc.r_pw.r_qf.,cf.osb&wrapid=tlif133988401258511

John

[fyliu]

For me my support is thin and I let a single stem go up each one. Maybe growers do several just in case one gets damaged by animal or disease.
If you grow in containers like me you have to think about how many plant you want to compete for root space.

[RufusWallace]

Hehe, indoor light is not a problem    Got big south and east facing windows plus 1000 watts of led light + fluorescent on 24/7.  Gotta love having cheap, clean electricity!  The challenge at least in the short term will be not breaking my budget on large pots and soil for transplants, lol 

Thanks for mentioning how heavy they get; that didn't occur to me, as I'm not used to heavy climbers (my biggest climber so far has been passionfruit).  Any clue how big they need to be to fruit?  I general, I just want to get my plants up to the minimum size needed to where it's possible induce fruiting.  I don't need a ton of fruit, I'm not looking to sell.  I just love being around my plants and nurturing them up to maturity... and possibly getting some rewards for doing so, to enjoy myself and to give to friends 

ok so you make use of lights to grow plants.. I never did that.. Will now get these lights and use them for plant growth

[Hollywood]

This is my set-up. I stuff socks with spahgnum moss and fruit tree fertilizer and tie them on top of the rebar at the top.

[LEOOEL]

Tim, that trellis is a beauty. I 've never seen anything like it. I don't have much experience working with wood, but I'd certainly would like to top off my wood pole with something like that. Thanks for the aesthetic/artistic and useful idea.

Or you can build something like this      May not be suitable for your indoor needs though...

[MarinFla]

Karen you could reinforce your pvc with rebar. I have rebar supporting underneath this. The wire fence and plastic lattice are wire zip-tied to the rebar.
It Started like this Jan 2012

Now it looks like this a year and a half later

[LazaroSpofford]

Oooh, awesome to know that you can fruit them in such small pots and such a small size    A couple fruits every now and then is all I need from dragonfruit.  I like the fruit because they're so beautiful; the taste is kind of bland, IMHO.  As for varieties, living in Iceland, I'm kind of stuck with the variety I have at least for now, heh    It's not that you can't get unusual plants here which are not adapted for the climate (I picked up my olive tree here for example).  It's just that the safe default assumption here for tropical non-houseplants is always "not available until proven otherwise".  I forget which variety I'm growing, it's been so long since I ordered it, but I did compare a couple varieties before selecting this one.

As for the light, well, you have to compare it to the sun.  Most of the amazon basin gets 3-5 kWh/m²/day.  So let's say 4.  That's an average of 167W.  The peak solar panel on a perpendicular plate on the surface is 1000W, but there's night, there's clouds, there's angles, etc. 

Now we look at an artificial lighting setup.  First efficiency comes into the picture - not luminous efficiency, but quantum efficiency (luminous efficiency takes into account how the human eye sees light, which is irrelevant for plants; the human eye sees green best while green is worst for photosynthesis).  You'll get up to 30% on a good tube.  LEDs can approach 40% external quantum efficiency.  Because of bulb age and not having optimal bulbs to begin with, let's say 25% and 33% respectively.  Then there's light loss.  On Earth, the sun is always striking *something*, and if you have a plot of plants, the light that escapes hitting your plants is offset by light that escapes hitting other plants and hits yours instead.  You set up grow lights indoors, part of the light will escape and hit... well, something you don't care about.  Let's say 60% is useful.  So right there are some pretty massive losses.  Now there's the spectrum to take into account.  Actually, this is an advantage for indoor growers, because a third of the sun's energy is in infrared, which is worthless, and the rest pretty evenly spread, while photosynthesis absorption bands aren't.  Fluroescents are sort of a mixed bag in terms of what visible spectrum they provide, but at least there's not much IR** -- let's say credit them with 120% of the sun in terms of spectrum efficiency.  LEDs, with blue and red, esp red, are spot on for photosynthesis; credit them with 200% spectral efficiency.  Note that we're not considering hormonal effects of a different spectrum than the sun; for example, while my dragonfruit loves all that LED energy, I know from experience that if I were to try to grow, say, lettuce under it, the lettuce would be horribly lanky and basically a disaster.  But here we're just talking about energy.

So, to match the Amazonian sun with fluorescents, you need 927W/m².  With LEDs, it's 421W/m².  Note that that's per square meter.  Growing even a couple square meters indoors like I do, and well... matching the sun takes a lot of light!  During the winter I'll have to replace pretty much the entire sun; there's several hours of "dim" outside but the sun won't rise over the houses to my south until late February or so.  During the summer at least I have those nice picture windows to help out. 

I really think that the number one limitation of most people growing plants indoors is not grasping how much energy plants really get from the sun and how little most indoor lighting provides.  Our eyes see light logarithmically, not linearly.  It may not look that much brighter outside, but it really is.  If we saw light linearly, outdoors would be blinding and indoors would be like a cave.  And it makes sense that it takes so much energy to produce food when you look at internal plant losses; food crops which are fully healthy and getting enough light (and everything else) range from a tiny fraction of a percent to 1% of their energy going into the final edible portion (fruits and vegetables), to a couple percent (grains), to as much as 10% in extreme cases like sugarcane.  So a 1% efficient plant in the Amazonian sun is actually only getting around "productive" 1 1/2 kilowatt hours of energy per square meter month!  That's 1200 food calories per square meter per month.  And if you "underfeed" the plant in terms of light, it's going to be needing all of the energy it gets just to try to stay alive.


** To be fair, there actually *is* a lot of IR, but it's far IR, heat radiating from the glass and ballast due to the efficiency losses - and since that's already counted under the efficiency losses, there's no need to count it twice.

Just perfect.. you have described the role of lighting in very effective manner.. Really glad to find such useful old post.

[OrganicJim]

Would like to make a comment on you having your lights on 24/7. I have designed several plant growing facilities for research facilities and all of them had the facilities set up so that they could give plants rest periods (night conditions). They were all of the opinion that too many hours of light stressed plants.

[TheWaterbug]

Or you can build something like this      May not be suitable for your indoor needs though...

Looks interesting. What does the base look like? Or is the post buried in soil?