Q/A #21 - Sarracenia Seedlings Under Humidity Dome

January 19, 2023

Q/A #21 - Sarracenia Seedlings Under Humidity Dome

QUESTION:
I have three small trays of Sarracenia seedlings, grown from seed, approximately 1 inch tall. Some of the pitchers have turned brown. Have you any idea why this may be? I sowed the seed at the end of August and we're currently in UK winter so they have been on a heat mat since the end of October, and they are covered. I regularly lift the cover and waft them to exchange the air. The temperature inside the containers is roughly constant at 20°C (68°F). They are standing in 2cm of water which I have changed once a month. Could they be too hot? Maybe it's too humid? Could it be a lack of light? The window is west-facing and the days are short and the sun is low. They're in a 50/50 of sphagnum peat and perlite the same as I always use. I have sprayed them a couple of times with diluted fertiliser, onto the plants, not the peat. Could this be the problem? Thank you for any advice you can give me.
(Submitted in January 2022.)


RESPONSE BY JEFF DALLAS:
Lack of light is the biggest issue here, and I would also add excess humidity. Over the years we have scrapped entirely using humidity domes for germinating Sarracenia. They cause more problems than they solve. An alternative approach is to sow the seeds, then cover them with a thin layer of peat; just enough to not be able to see them. This helps with fungal issues. After that, spray the soil with a fungicide.

Here's what I would do with where you currently are with this. Part of what is probably happening is that plants have gone dormant since they are receiving natural light. The short days are inducing dormancy since that is more brought on by photoperiod than temperature. If you have them on the heat mats, turn that off. Gradually open up the covers with the goal of removing them after about 2 weeks. Let the plants harden off gradually. This will be time consuming, but will help with fungal issues. 
Keep some water in their trays, but just enough to keep the soil moist; you don't want them waterlogged. Gently clip away any dead leaves.
Watch the plants for any signs of new growth. Once you see that, consider adding a bar or panel type LED grow light over the plants. (A fluorescent shop light will work just fine too if you have any of those laying around still.) Match the photoperiod to the outside day length.
Also, don't pull any seedlings up that look dead; they may just be dormant. Plants like S. oreophila and S. flava lose their pitchers entirely in winter. Wait until spring, and then if they are still brown, remove them. Finally, don't do any fertilization during winter. They are not growing right now.
In late Spring or early summer I would start selecting seedlings you want to keep and put them in small pots. This would also be a good time for those to go outside.


• Submitted in January 2022. The original question and response have been edited for publication.
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