Heat tolerance of Sarracenia seedlings

[meadowview]

Hi Folks:

I would be interested in hearing any qualitative comments on heat tolerance of Sarracenia seedlings and at what temperature growth is inhibited. I have not seen any rigorous experiments on this matter but I think I am seeing inhibition somewhere in the 80-90 F temperature range.

Comments?

Sincerely,

Phil Sheridan
Director
Meadowview Biological
Research Station

[Brian Barnes]

Hey Phil!

Yes, I do agree with you totally.

My Sarracenia seedlings also appear to go "semi-dormant" once temps hit above 80-85F. Then, I've noticed that growth will slightly resume in Fall, along with the Fall pitchering "rush"

Here in Central Fl. (inland), the fore-mentioned temperatures combined with high constant tropical humidity and no sea-breeze/air movement seems crippling. Even the adult plants seem to despise 90F temps, combined with the humidity factor (often at a constant 100%)....and no real nightly cool-down at all.

Happy Growing,

Brian.

[meadowview]

Hi Brian:

Thanks for the comments. We will be expanding our greenhouse considerably this fall. We will have several evaporative coolers in the expanded section, and combined with shadecloth, I think we can get our Sarracenia seedlings to grow all summer instead of stagnating under the smmer heat. We'll see.

Best,

Phil

[Not a Number]

Well, I just put out a tray of seedlings this spring.

I used the Steve Millar (aka Bugweed) accelerated growth method of 24hr lighting 7 days a week and soil temperatures ~81F.

I noticed no growth inhibition, only growth spurts after feeding when the seedlings were big enough for flightless fruit flies.

I did not have space for a control group.

I'd like to combine this method with the recent data of fertilization and see what the results are like.

For more information on Steve Millar's method see:

www.terraforums.com/forums/showthread.php?t=107339

[meadowview]

Hi Not a Number:

Your soil temp, 81 F, then is consistent with lack of inhibition. We don't know the temperature where inhibition occurs yet but it is somewhere between 80-90 F. So.. if you saw no negative effect at 81 F that helps us bump up the number.

We have also found significant positive effects from fertilization of Sarracenia seedlings. See our VAS abstract "Rare Plants in the Classroom; Potomac Elementary School and the Toyota Tapestry Grant. 2000. Virginia Journal of Science 51(2): 130." at www.pitcherplant.org/Abstracts/rare-plants-classroom.html for the results. I also have a nice bar graph of our statistics.

Not a Number, how did you measure your soil temperature?

Sincerely,

Phil Sheridan
Meadowview

[Adammmm]

im just going to guess for NAN, but i think he may have used an electronic meat thermometer.

[meadowview]

Hi Adam and Nan:

Soil temperature is useful for our question about inhibition of Sarracenia seedlings but the real variable we are after is air temperature.

Best,

Phil

[woodnative]

Phil-
I have no clue how much growing space you have at Meadowview, but would it be cost effective to set up a temperature control room with light for the very young seedlings? This seems to work well, at least on a small scale, and it seems like you could control things easier than in a greenhouse. I grow my seedlings (just a few for hobby purposes, nothing on the scale you are experiencing) under cheap shop lites with cheap cool white fluorescent bulbs. They are within about a foot to 18" from the bulb. I have the lights on a timer for a 16 hour photoperiod. The room currently stays in the mid- 70s F. The seedlings below are 8 months old, germinated in mid-December of 2008. They were transplanted twice...germinated in a communal pot, transplanted at a young seedling stage to drinking cups, and recently into their current pots. The biggest, about 10" tall is the biggest of a hybrid group ('Red Sumatra' was the seed parent). The plant on the left (smaller) is an S. oreophila. The two plants on the right are from a red flava, one of the two is very red. Of course there is a purp in front. I think these are good size for their age. Chris in NJ
<a href="http://smg.photobucket.com/albums/v468/Woodnative/?action=view¤t=Sar8monthsAug09.jpg" target="_blank"><img src="http://img.photobucket.com/albums/v468/Woodnative/Sar8monthsAug09.jpg" border="0" alt="Sarrs8monthsoldAug09"></a>

[woodnative]

Lets try this again. I have not used photobucket for a while.....

[meadowview]

Hi Chris:

I had great success as a kid raising Sarracenia under fluorescent lights in the basement. This was fairly small scale.

Our situation at Meadowview is where we are raising hundreds of different crosses and tens of thousands of seeds. The scale is far beyond what we can do under lights. I think we have the protocol tweaked pretty well now for large scale production but I wanted to share the concern over heat inhibition of seedlings.

Best,

Phil

[woodnative]

I figured as such. You and Meadowview do good work. I would love to see your facility in person. I will say that seedlings from the same batch, planted outside this Spring, are not as large, but have done ok. However, this has been an unusually cool and wet summer.....not the typical several weeks in the 90s of most summers.

[Alexis]

I have plenty of seedlings living in a cold frame. Back in June I forgot to open the lid and they cooked. Outside temps were 28C (82F) in unbroken sun, so I wouldn't be surprised if they reached 45C (113F) inside.

All plants suffered scorching and some lost a lot of foliage.

The 3 year old plants looked poorly but have since recovered no problems.
The 1 year old plants also looked poorly and about 20% died. The rest have recovered no problems.

It seems the larger the plant, the more resilient they are.

[sunbelle]

Hey Phil,
Well, as you know, we are in south Florida, so we are truly in a near tropical climate. Our Sarracenia seedlings are subjected daily to temps up to 95F + and some grow, albeit slower, and others simply perish--usually the plants you would consider the "runts of the litter". There are always that 10 percent that grow faster and they seem more resistant to extreme temps. We germinate our seed in the greenhouse under shade, and once they hit a certain size, they go out onto the Sarr. benches. We would agree with Alexis: as they become larger, they become more resilient. We also have volunteers, and while those seedlings are fewer in number, they tend to be very strong growers.
Here in the sub-tropics, many of our Sarracenia take a mid-summer dormancy. The Carribean sun is incredibly intense.

[meadowview]

Hi Sunbelle and others:

Thanks for the useful comments. As one would expect, larger plants are going to be more resistant to environmental stress. Also, Sunbelle good point on the runts. We have noticed that out of most Sarracenia crosses there is a proportion of "runts" that clearly aren't playing with a full deck.

Sunbelle, fabulous photos on your web site of the ocean cliff side Nepenthes!

Best,

Phil

[Not a Number]

Hi Phil

The thermostat probe for the heating pad was inserted into one of the pots to a depth of about 1.5-2 inches (3.8-5.1 cm). I used my darkroom dial thermometer, the probe was inserted to about the same depth in various pots. I also used it to measure the temperature of the tray water - about 4-5 degrees F warmer than the media.

I have no air conditioning in the room were I grew the plants so on Dog Days or during the "Santa Ana Winds" room temperatures can get up into the mid 80s to low 90s F at times.

-Warren