Giving Seedlings the Cold Treatment

[sjamesNorway]

Originally Posted by geoffrey44

Thought this might be of interest.
These two have been grown under lights in my garage which receives no heat.The temperatures have not exceeded 55f in the last four to six weeks and most of the time have been around 45 to 50f..I am growing a range of tomatoes and even the chillies are progessing very well.The plants certainly have nice thick stems and are quite robust with really good colour. They are going to have to continue in this environment for another 4 weeks or so then I will start to plant some of them out but cover from the winter weather will be in vogue.

Beautiful plants! I'm almost as green with envy.

Steve

[bower]

Ditto on the beautiful plants.
First blossom megabloom is pretty much expected here. My seedlings always get the cold treatment, and I do think it's a side effect of cold. I've been varying the timing and extent of cold exposure and it doesn't seem to matter...

[Fusion_power]

Megablooms are a symptom of stress. You can induce a plant to produce a primary megabloom by restricting water, overheating, etc.

[geoffrey44]

In answer to an earlier query I can confirm that this method works exactly the same way with chillies (peppers )
I am currently growing habs, Trinidad scorpions and a variety of other chillies under the lights and with the temps mentioned in my earlier post. They are stocky and with the same spread of intensely coloured foliage. They are however much slower growing than the tomatoes which despite the cold are growing at least an inch each week...It is almost frightening !!
Best wishes to all,,, Geoff

[amideutch]

geoffrey Beautiful plants they are.

Steve Concerning the megablooms I never noticed.

[amideutch]

My bad.

[geoffrey44]

I don't know about the megablooms but some of the plants are developing very healthy looking flower spikes. At this stage of their growth I don't know whether I should leave them or remove them,,,I am inclined to the latter as I believe it is more important to encourage growth rather than pander to their reproductive urges...Any thoughts or suggestions ???
As an aside at Marsha suggestion I tried a dwarf...One of her Perth Pride which she so generously provided... It shows exactly the same characteristics but in a dwarf format...If any interest I will organise a pic showing the comparison...
Geoff

[sjamesNorway]

Originally Posted by Fusion_power

Megablooms are a symptom of stress. You can induce a plant to produce a primary megabloom by restricting water, overheating, etc.

I guess stress from overheating in that case. They were moved into a greenhouse after hardening outside. It got up to 90*F the first day, before I opened it up. (Live and learn...) I've since invested in shading.

I've removed the megablooms because I've read that the resulting tomatoes will be misshapen, and not very edible.

[amideutch]

I don't know about the megablooms but some of the plants are developing very healthy looking flower spikes.

This is one of the benefits of the "Cold Treatment".

Tomato plants properly exposed to a cold treatment develop large cotyledons and thick stems, with fewer leaves formed before the first flower cluster, up to double the number of flowers in the first, and often the second clusters, and higher early and total yields.

Ami

[geoffrey44]

Well here is the Perth Pride which has now been planted out in the garden for about 5 weeks.. Weather has been terrible...coldest July for 20 years ..rain,wind,frost...you name it...we have had it. The plant has been protected from frost and the worst of the windy conditions but fully exposed to all else... It is a dwarf after all !
But looks good...a bit of warmth and hopefully away
it goes...and I think its cold upbringing has contributed to its present healthy stature...
Geoff

[amideutch]

Looking good Geoff.

Ami

[geoffrey44]

Hi Ami
What will be really interesting will be to see what happens when the weather warms a bit... There is always the chance that the plant wont like the change and could well sulk for some time... In which case this all becomes an exercise in futility...
But that fact that the plant is just not sitting and is actually growing in these cold conditions gives me some hope that the advent of warmth will excite it to greater things..
We can but wait and see

[greenthumbomaha]

Snow again tonight but it will be time soon.

I've set a tray by a cold window since I read this a few years ago. I re-read this every year at least twice to the point where I confuse myself! To be sure I miss or forget something, or just need to speed up as the weather has been crazy.

Seedlings are germinated with bottom heat and artificial light until the first few seedlings in the tray appear and then the tray is removed from the supplemental heat source but are still subject to (16?) hours of artificial and/or windowsill light.. someone said 5 hours artificial is sufficient even on cloudy days.

When the first true leaves appear tray is moved to a cool area for cold treatment for desired period.

This is where I get confused. I normally start fertilizing shortly after the first true leaves develop. Should fertilizing be delayed until the cold treatment period is concluded and trays are moved to a slightly warmer area?
Thanks!

- Lisa

[Dutch]

Hi Lisa, I hope Ami checks the board tonight and answers your question.

I just wanted to add that to truly give your plants the cold treatment you should not talk to them and you should try to act as if they are not even there.
Dutch

P.S. Whether using the cold treatment or not, I start fertilizing (bottom watering) shortly after the first true leaves develop using a weak water soluble fertilizer.

[greenthumbomaha]

Dutch, that pretty much answers my question but I didn't see where Ami mentioned fertilizing. Ami is probably in rem sleep about now. I hope we don't give him the hiccups in his sleep.

So weak fertilization during the cold treatment period is part of the process. Just checkin' to make sure they don't cancel each other out. And no bad talk as I bend down to the cold floor to water each of the 72 cells. Got it, thanks!

- Lisa