Start Date for Cold Treatment

[Farmette]

Anyone in here southeastern WI use the cold treatment for their seedlings and if so when do you start the seeds? I want to try this method and need my plants robust and healthy by the 2nd or 3rd week of May. If no one in this area uses this methods, is there any advice from the rest of you that use it? Thanks

[PNW_D]

Farmette

found this info on back of very old tomato seed pack from Cooks Garden:

Start tomatoes 8-10 weeks before the frost free date. Sow seed in flats 1/4" deep and germinate at 72 F or higher. Grow the plants at 55 F nights and 65 F days for the first three weeks, then keep the temperature at 65 F or higher with as much light as possible until setting out. Thin the seedlings or transplant to larger spacings as soon as the leaves of adjacent plants touch.

[Boutique Tomatoes]

I'm north of you but last year I sowed on or about March 15th and moved them to the unheated garage as soon as I'd separated and potted the seedlings.

I'm definately doing it again, last year was an unusual weather pattern but I had early fruit set, a few tomatoes ripe in late June and then tomatoes coming like gangbusters in early July which was a first for me since moving here.

[amideutch]

Start your cold treatment just after the seed leaves unfold for 10 days to 3 weeks at 52 to 56 degrees F. The duration of the cold treatment is determined by the time required for the plant to develop to the two-leaf stage. I believe the last day of frost for your area is around 1 May.

Ami

[Dutch]

Hi Farmette,
I have used the cold treatment for my tomato seedling here in southeastern Wisconsin many times. I have started seedlings as early as mid February and as late as the early April. Mark’s suggestion of mid March sounds like a good date to pencil in for our climate or perhaps a week earlier.
I have had the best luck starting my seedlings for cold treatment about two weeks earlier than normal for the area. There are a lot of variables to this, like container size, growing medium, watering schedule, temperature control, available light or lighting and other environmental factors.
Dutch

[PNW_D]

A bit more detail ..

from Growing greenhouse tomatoes in soil and in soilless media Dr. A.P. Papadopoulos Research Centre Harrow, Ontario
Under a cold treatment regimen, place young tomato seedlings in a day and night air temperature of 50-55F/10-13C for approximately 2 weeks, while providing as much light as possible for 9-12 hours. Seedlings should be subjected to cold treatment just after the seed leaves (cotyledons) unfold and the first true leaves start to appear (see below). Shoots kept at low temperatures at this stage of growth produce a small number of leaves below the first flower cluster and therefore flower earlier; roots kept at low temperatures cause branched clusters, i.e., many flowers in the first and possibly the second cluster. Cold temperatures during both day and night are effective.

stages in seedling growth used for initiating (plant A) and terminating (plant B) the cold treatments
The cold treatment increases the number of flowers but does not influence the setting of fruit. If later conditions for fruit setting are right, a greater number of flowers will set fruit because of the increased number of blossoms. If, however, the temperature for fruit set remains less than ideal, the pollen does not germinate and grow normally, resulting in poor fruit set and cat-faced fruit. When the cold treatment is used, seed 10-14 days earlier than usual to compensate for the slow growth rate during the cold treatment. The growth medium in the seedling trays must be sterile, because when plants are grown at relatively low temperature the danger of damping-off is increased.

[Farmette]

Originally Posted by Dutch

Hi Farmette,
I have used the cold treatment for my tomato seedling here in southeastern Wisconsin many times. I have started seedlings as early as mid February and as late as the early April. Mark’s suggestion of mid March sounds like a good date to pencil in for our climate or perhaps a week earlier.
I have had the best luck starting my seedlings for cold treatment about two weeks earlier than normal for the area. There are a lot of variables to this, like container size, growing medium, watering schedule, temperature control, available light or lighting and other environmental factors.
Dutch

Hi Dutch:
Last yr I got some Champion II seedlings from you and I remember you saying they had the cold treatment. They were nice and stocky and grew very well through the season. That is why I want to try it this year. I remember you put yours out In your greenhouse and am wondering about how many weeks into it you did that.
Thanks!
Chris

[Farmette]

Thanks for all your opinions and input...I think I a going to try this method, but will also grow some in traditional fashion as a backup just in case.

[Dutch]

Originally Posted by Farmette

Hi Dutch, Last yr I got some Champion II seedlings from you and I remember you saying they had the cold treatment. They were nice and stocky and grew very well through the season. That is why I want to try it this year. I remember you put yours out In your greenhouse and am wondering about how many weeks into it you did that.
Thanks!
Chris

Hi Chris;
Those Champion II’s were started on Monday 02/27/2012, but there is a whole lot more to it than that. The propagation table is four foot by four foot and has sixteen 6500k four foot bulbs in it. Fans keep the table temperature in the mid to upper 60’s degrees Fahrenheit. It was in the basement of the house when I bought the property (1972) and it still is. Behind the house were five large commercial glass greenhouses. My mother had worked in the greenhouses of the former owner. We continued the greenhouse business well into the 70’s.
I told you there was a whole lot more to it. Basicly it's a whole lot of light and quite moderate tempertures. I will take some pictures tomorrow.
To be continued…
Dutch

[Farmette]

Thanks Dutch...looking forward to the pictures.

[Dutch]

Originally Posted by Farmette

Thanks Dutch...looking forward to the pictures.