Time & temperature for fridge dormancy.

[richardhole]

Hello

I am on the Atherton Tableland near Cairns in Australia. We have had above average temperatures this winter and have not had the usual cold snap. As a result, I heard it could be an idea to put Sarracenia and Venus Fly Trap bulbs in the fridge. My Sarracenias have mostly dead growth. However, some of them have some young shoots that would develop into pitchers. Some of my Venus Fly Traps have a lot of stunted growth and one produced a flower yesterday.

Do you suggest I put them in the bottom of our fridge for the last month of winter bearing in mind my below temperatures? It would probably be better if I had put them in the fridge a month or two back. However, I thought we would have a cold snap.

The temperature of our fridge reaches a minimum of about 2.5 degrees Celsius. However, the temperature is often a couple of degrees higher than that. Should that be a good temperature? I assume that it would probably be best to leave a couple of the younger pitches or fly trap shoots on the plants. Is that a good idea? I plan to wrap the bulbs in damp paper towel in a plastic bag after removing the dead growth. However, I may put the whole pots of a few of them in a bag in the fridge where the soil is moist but not too wet. If I put them in the fridge in the next couple of days, how long would I leave them in there for considering it is now late winter?

Records from my home weather station in a standard Stevenson Screen indicate that the mean minimum for July was 15.8 degrees Celsius. The minimum was 12.6. The mean maximum was 22.3. For June the mean minimum was 14.6 degrees. The minimum was 11.9. The mean maximum was 22.9. More information is at weather.org.au/tolga

Your help is appreciated
Regards Richard.

[Aidan]

You will likely achieve more harm than good, so I suggest that you leave well alone.

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[ICPS-bob]

I agree with Aidan. Once growth resumes, the plant has decided dormancy is over. If you put them in the fridge now, it will not help, but could likely damage both the Sarracenias and VFTs. Missing a full winter's dormancy is not a big deal.

[richardhole]

Hello

Thanks for the suggestions.

One thing I also meant to mention is that some of my plants have scale insects and others are not looking very well and may be on the verge of dying and they contain no new growth. Perhaps putting these plants in the fridge could help.

On many of my other plants there is no new growth and on others there have not been any more young shoots than during the middle of winter so it would appear that those plants are still in dormancy and are not starting to get out of dormancy.

For these plants do you suggest putting them in the fridge for about a month?

Your help is appreciated
Regards Richard.

[Aidan]

Aug 1, 2010 17:38:09 GMT Aidan said:

You will likely achieve more harm than good, so I suggest that you leave well alone.

With regard to scale, I believe that you have already been given advice concerning the use of insecticides.

[richardhole]

Hello

Thanks for the earlier suggestion on scale on Nepenthes. They are a totally different pest to what I have on the Sarracenias. I think they are Mealy Bugs on the Sarracenias. I prefer to avoid dangerous insecticides. However, for the Nepenthes I plan to get someone to spray or dip them in a strong insecticide.
I thought that pulling the Sarracenias bulbs and roots out of the soil and washing them and putting them in the fridge could also help kill the pests to save using strong insecticides.

I appreciate the earlier advice suggesting not to put Sarracenias and Venus Fly Traps that are starting to shoot in the fridge. I have passed that suggestion on to the man who talks about gardening on the radio because a couple of days ago he suggested that people should put Sarracenias in the fridge now as it has been a warm winter. I was not planning to do this before I heard what he said

A problem I have is that there is a lot of moss (not sphagnum) and slime on the surface of the soil and I am a bit concerned that it may smother some of the plants. So I thought that taking the bulbs out of the soil and washing them may help. However, I only plan to do this with the plants that are not shooting. Most of them are not producing any new shoots. I wonder if a thin layer of sand or sphagnum moss on the surface of the soil will reduce the amount of moss and slime after I repot them. Washing the potting mix well or letting water leach through it for a long time may help

I value your suggestions

Your help is appreciated
Regards Richard.

[ICPS-bob]

I clean up, divide, and repot my VFT and Sarracenia in spring just as the plants are coming out of dormancy. This is a good time to replace the potting mix. In early spring, the plants are getting ready for sustained active growth and are less likely to become diseased. A top dressing of coarse silica sand might reduce your moss and slime problem because the surface will quickly dry and become more inhospitable to them.

[richardhole]

Hello

Thanks for your suggestions.

Another thing that I should have mentioned is that my Sarracenias produced a number of deformed pitchers in the late summer and autumn. I heard that this was due to fluctuating temperatures. I purchased the plants from a nursery over 1000 km away so the change in climate may have caused this. Do you think so?

I also purchased my Venus Fly Traps from this nursery. They have not gone dormant at all through the winter. They are producing stunted growth and a stunted flower. A carnivorous plant specialist at the local Botanic Gardens stated
“My advice is if your plants are doing odd things, like your VFT putting up flowers, it's a sign of the confusion going on inside the plant cells, they don't know if it is spring, summer or what, so get them in the fridge! Even if it is only one month and you bring them out in September I think you'll find that it will be enough to cause dormancy to be triggered. Maybe do an experiment and leave a couple of plants out of the fridge and compare the results in the growing season.”

Do you think this could be a good idea?

Your help is appreciated
Regards Richard.

[ICPS-bob]

I just realized that your climate and latitude (17S) is rather tropical. Trying to grow temperate plants, such as Sarracenia and Dionaea under such conditions can be a real challenge. I suppose you have seen this video


The Green Culture forum (Singapore) has a lot of members trying to grow temperate CPs in the tropics.
www.greenculturesg.com/forum/index.php?/forum/54-carnivorous-plants/

[richardhole]

Hello

Thanks for the video link. Someone else also referred me to that video. I notice Trevor puts his plants high up in the refrigerator. He must have had the thermostat set fairly high. For an average refrigerator, people say to put them in the crisper at the bottom which is supposed to a bit warmer than the rest of the fridge. I have put Venus Fly Traps in the crisper and they grew well. However, last year someone moved them from the crisper to the second shelf in the fridge and none of them grew. They seemed a little jelly like so they must have became too cold. I think it is important to have a thermometer in the fridge to make sure the temperature does not go below about 2 degrees. Trevor indicated that the temperature should go down to about 5 degrees. However, setting the thermostat higher would cause people like me some problems because the fridge also contains food that needs to be cool. What I did is wrap the bag containing the plants in newspaper and put them in a cardboard box to insulate them from the lower temperatures. I often notice that our fridge is about 6 degrees.

I also notice that Trevor in the video does not wrap the rhizome and root ball in paper towel, sphagnum or anything. He just puts the washed roots in a plastic bag which should work as the roots would be damp and contacting each other to retain moisture and the bag would prevent them drying them out. I may try that next time.

I rang Trevor and he said he often wrapped them in sphagnum moss. He said he sold his collection a few years ago but hoped to get a few again soon when he gets time.

Your help is appreciated
Regards Richard.