I've been experimenting with growing Nepenthes hydroponically since March 2015, so for about a year and a half now. I'd like to share my results in this thread, and then give some details about my method. Thanks to TF member knuckles for sharing with me his experiences growing Nepenthes hydroponically at the start of my experiment.
So why grow Nepenthes hydroponically? A few reasons:
1. Some of you may know that I've been interested in growing Nepenthes in inorganic media to avoid repotting. In my experience, Nepenthes don't like repotting, and it's a very difficult task with large plants. Since some inorganic media theoretically never decompose, repotting is no longer necessary.
2. Automation. Having a system that waters my plants for me is a huge time saver. Since I do not have a greenhouse and do not grow outdoors, I can't rely on misters. A drip irrigation system fits my circumstances best.
Anyway, some before and after photos should give an idea of how the experiment went. NB: My photos below may be used & reproduced for any non-commercial purposes whatsoever. Attribution appreciated but not required. Click any of the photos below for full-sized versions on Flickr.
N. Hopeful Monsters (open-pollinated merrilliana hybrid).
2015-03-29: Growing in rockwool cubes prior to transplant:
2015-06-22: three months later, after hydroponics, in the same pot. Decent amount of growth.
Roots before (left) and after (right):
N. splendiana x Redneck
2015-04-22: Growing in 3.5" / 9 cm pot before transplant, in rockwool cubes.
Left, 2015-07-23: After 3 months in hydro, 1 gal. (size #1) nursery pot. Right: eleven months after the photo on the left, 2016-06-22. Same pot in both pics. The plant had 3 vines in the right photo, still holding onto some of its pitchers from the previous summer:
N. Josefita, clone 2. Unregistered grex name. splendiana x Song of Melancholy.
Left, 2015-11-08: Just repotted from 3.5" pot into 1 gal (size #1) nursery pot. Right, 2016-04-04: Five months later, same pot.
Roots after. About 85% of this was grown while in hydroponics.
N. Los Alamos. Unregistered grex. Splendiana x a different Song of Melancholy.
2015-10-18: Just repotted into 1 gal. nursery pot, was growing in rockwool cubes.
2016-05-11: Seven months later, same pot. In spike.
For the following plants, I only have after shots, but I think they're still informative photos.
N. splendiana, 2016-03-06. Fifteen of the 18 leaves pictured were grown hydroponically.
Roots after growing hydroponically for several months:
N. ventrata, 2016-04-23. About 15 new leaves in about 5 months of hydroponics. The white rope divides the pre- vs. post-transition to hydroponic growth.
N. graciliflora (?) aka alata var. boschiana mimic, 2016-02-27. Two-thirds of the vegetative mass shown here was produced while on hydroponics.
Here's a Fairyland (sanguinea x clipeata) grown in hydroponics, left & middle, and some nice pitchers from other plants grown hydroponically (Josefita, splendiana, maxima x vogelii).
My splendiana x ((veitchii x maxima) x veitchii) also made its biggest pitcher ever while on hydro. I could not get a whole plant shot, as it's lost in a tangle of other plants:
In that tangle pictured above are also growing N. Rokko 'Wolfplant', Red Leopard, and Isis (spathulata x albomarginata natural hybrid), all hydroponically.
Other plants that have succeeded for me hydroponically include
-additional clones of Los Alamos
-boschiana x fusca
-a wild maxima-sanguinea hybrid
-(spathulata x bongso) x (boschiana x (spectabilis x veitchii)?)
-lowii x campanulata
-poi dog alata hybrid
-"thorelii" x alata
-Redneck (Toyoshimae x maxima dark)
A few plants that have not done well include eymae x ephippiata and a clone of Song of Melancholy (boschiana x (spectabilis x veitchii)?). There are mitigating factors to consider in these failures. I'll discuss those in a subsequent post.
These plants are all grown in 100% coarse perlite that has been sifted through a #10 bonsai screen. Pots are all #1 size, commonly know as 1 gallon pots in the US (although they are not, in fact, a gallon by volume). Plants are watered 4 times daily for 15 minutes each through drip irrigation on a recirculating system. I fertilize weekly with a 9-3-6 fertilizer. All plants are grown indoors without supplemental humidity. I'm in the process of converting the rest of my collection to hydroponics.
I'd be happy to answer any questions, but I can't guarantee a speedy reply. Patience is appreciated