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16 Hour Photoperiod Okay?

jimscott

Tropical Fish Enthusiast
Some of my sundews are thriving and some are struggling. Most of them are either on the south-facing grow rack, with a light 2-3" above them or in the terrarium setup. They get ~16 hours of light per day and I'm wondering if that's too much time and perhaps leading to dormancy for the pygmy sundews. I do see a lot of stipules for the ones that look horrible.

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Whaddya think?
 
which dews are doing poorly?

I can't see why a 16 hr photoperiod would hurt any of them...

maybe someone can come clear it up for ya :)
 
The pygmy sundew gemmae I sowed this fall.
 
i've only got a couple pygmy's so hopefully someone will come to help out, but i'd be interested in the response here becuase I run most of mine on an either a 16-18 hr photoperiod and havnt had any problems so far...

how exactly do they look bad? like weak growth? slow growth? lack of color?
 
wow jim!how i wish i have a large sunny window like urs..very nice grow rack too..think i'm gonna follow suit if all my ceph leaf pulling strike for me..i did some 'pruning' today and end up with 32 pullings..hehe..
 
I dont see why 16 should be too long, i give mine 18 and they're doing great. I'd look for something else causing the problem.
 
Try to post some pics. Light will not trow them in dormancy but heat sure will. I have a setup for gemmae starting and i give them 16h a day. I keep them there for the first month of their life. I did had one or 2 for longer time in there and did not seem to be affected in any way...they was just growing like crazy. Also your soil mix can be the cause of your problems with some.
 
There's no heat to speak of. They're in room temp. They're in a mix of mostly sand to peat. Generally speaking, the are getting distilled water. The fluorescent light is ~3" above them, with the sun shining in on them, southern exposure. Some are doing well and some look horrible. No pictures available for now. They don't grow.
 
Depending on your room temperature it COULD affect them. I have mine in no lower then 75 degrees and a high of about 84-85. The lights do add some temperature to them though. Your mix sounds just fine as well as the watering. Give them some time maybe? I had a few which I thought were going down hill but I just let them be and adapt and they look just fine now. I still have some D. occidentalis that just dont look as good as my other pygmies, hardly any dew but they grow like normal so i'm assuming it's the lights though they're 3 inches away from them...

Maybe check for fungus gnats or try rinsing the peat if you dont already do so when potting? That's really all i can think of : /
 
  • #10
16 hours has worked very well for me. Seems like an ideal photoperiod, since it encourages all of my sundews to flower. What size of pots are you using for the pygmies? I know they like larger pots, but haven't had trouble using 4-inchers. It seems to me that the only thing that truly encourages pygmy dormancy is when I let the media dry out. They flower and grow like crazy even in higher temps and long photoperiod as long as the media is sufficiently moist. So since it looks like you're already giving everything enough water, I really don't know what the problem would be.
 
  • #11
I've moved the struggling ones to the terrarium / heated fishtank. Maybe that'll perk them up. It's only about 85 F in there and more humid. Same lighting and I turn the heater off for the night. We'll see what that does. Thanks for the feedback.
 
  • #12
Jimscott, in Australia the summer photoperiod is 13-14 hours. The autumm photoperiod is about 10-11 hours. Pygmies go dormant during summer months. Last November, many species were already dormant and done with flowering when the day temperatures were 63-68F.
 
  • #13
Ever since day 1, my terra has been on a 16 hour photoperiod (5am-9pm), i've had a capensis, binata multifida and an aliciae and they are thriving. since then, i've added anglica, rotundifolia, lanata and adelae.
i do realise that the temperates need to come out in late summer, as to induce dormancy... but they love it in there.
 
  • #14
I have a small pot of pygmies which I've been growing for about a year and a half now. They get around a 16 hour photoperiod as well, it depends on how long I'm awake. Since all my plants grow on a table next to my bed, facing a north window >:eek: As far as I can tell, they have had no issues receiving light for such an extended period of time. I will say, they are in a state of permanent bloom though, and I have had a horrible time getting them to produce gemmae. I would love to get some gemmae, so I could repot my current batch with some insurance, but that's off topic.

The only time these plants have looked bad is when I left them here on spring break. That meant 9 days without any fluorescent light, and a closed shade on a north facing window. Essentially no photoperiod. They are still recovering. ;-)
 
  • #15
Jimscott, in Australia the summer photoperiod is 13-14 hours. The autumm photoperiod is about 10-11 hours. Pygmies go dormant during summer months. Last November, many species were already dormant and done with flowering when the day temperatures were 63-68F.

I know! So why are we all trying to provide 16 hours? Does 16 hours of fluorescent light or that which shines through the window offset 13 hours of direct sunlight?

Here are pictures from the same rack, showing sundews that are thriving and those that are struggling.

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I'm thinking that there were a couple times when the tray was essentially dry, combined with the leaching of something bad in the water, causing a surface film. But I can't prove that.
 
  • #16
Well, at least your capensis is doing well!
 
  • #17
Well, at least your capensis is doing well!
:-))

Here's basically what I do to help the plants on the grow rack:

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The first two rows get sunlight through the glass door and the last two rows get the artificial lighting.
 
  • #18
I wish I could provide some input regarding the indoor photoperiod best appropriate for the pygmy sundews, but all mine were mostly grown outdoors except in the cold months. I hesitate to give newbie advise to a long time grower, but consider the isssues of substrate purity. I always tried to use well weathered peat in my mix for these Droserae, and with a higher silica sand ratio than for many other species in the genus. Seeing mosses sprout so early in the pot makes me wonder. Nutrition as well may play a role in the lack of growth. Over heating is not good for these plants and can stimulate dormancy, and stipular development is an indication of impending dormancy. Wet and hot in a terrarium is contraindicated if dormancy is near. Many of the pygmy species I grew did go dormant in the summer months, and showed the best growth between March and June when the photoperiod was naturally less than 16h and the temps averaging in the 70F range. I found all the species always did best outdoors and speculate that a naturally increasing and decreasing photoperiod might be why. Few growers adjust their light periods, and the natural adjustments in daylength may contribute to their well being, just as has been discussed with the Petiolaris group, where someone speculated that an extended photoperiod might be a dormancy trigger. Gut level feelings tell me that your plants are headed towards dormancy....you don't list the affected species, but some pygmys are very sensitive during their mandatory summer dormancies and need both drier conditions and increased air circulation. Drosera mannii is one I could see the tag on, and that one fits the bill. I suggest (with some trepidation) that you try to maintain moisture deep in the pot while allowing the surface to become nearly dry, and keep the air moving as best as you can. Humidity is not wanted or needed during dormancy. Most growers want to grow their dews "wet" but the pygmy species are drought tolerant in the extreme, and I've had them growing in nearly bone dry substrates. For the summer sensitive species, I found indoors close under lights with a fan worked best, vs outdoors. I believe I used about 16h and with a gradual reducition over the summermonths until fall when good growth was again noted prior to gemmae production. I hope this helps amigo!
 
  • #19
Jimscott, previously when they turned dormant, they don't produce gemmae and rotted away soon after. I decided to shorten the photoperiod for my pygmies and soon, they started growing again. With the high temperatures here year round, the plants go dormant as and when they want. IMHO Shortening of the photoperiod keeps them growing at least.
 
  • #20
Tamlin Cindy: Thanks for your invaluable help! I'll pu them outside as soon as the overnight lows are finally over freezing... which won't be in the next two weeks. Maybe the sunny window sill is the best thing for them right now? That's what I'll do.

Funny how the "down under" sundews go dormant in the same months as our Northern Hemisphere temperates - but for different seasonal reasons.
 
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