Seedling growing temperature?
 

I've read that seedlings should be grown in "a cool spot", and that a temperature of about 65F (18C for me) is good. What I haven't been able to find, is an answer to the question of where to measure the temperature. The temperature under the lights during the day is considerably warmer than the room temperature. (At night it's no problem. They're the same.) Any advice?

I think you will be fine as long as the lights dont cook them.
I have had seedlings in my garage with temps in the 50'sF 10's C for you.
I have no idea what the temps were with the lights on.
I didn't have any reflectors up around them so they were open on the sides.

Worth

I don't think you need to worry too much over the temperature as precisely as you are. Ambient air temp measured close to the plants is fine. To keep the stems sturdy you can grow cool and on the dry side, and keep a fan on them for a little bit each day. Are you growing tomatoes or other plants? tomatoes can take it a little cooler than peppers and egg plant.

I've started plenty of seedlings in my greenhouse, where it gets over 90 degrees on a sunny day. They all seem to do fine.

Thanks all for the input. This is my second year starting only tomatoes from seed. Last year my plants were leggy, and I've read that a cool environment will help avoid this. (And I tend to be a perfectionist.)

Steve

[QUOTE=sjamesNorway;456764]I've read that seedlings should be grown in "a cool spot", and that a temperature of about 65F (18C for me) is good. What I haven't been able to find, is an answer to the question of where to measure the temperature. The temperature under the lights during the day is considerably warmer than the room temperature. (At night it's no problem. They're the same.) Any advice?[/QUOTE]
You would need to measure the temperature under the lights. That's how warm the plants will be and that will decide how fast the physiological processes can run. The warmer, the faster a plant can grow. (which in this case is not good).

Are the plants leggy this year?
When did you start them?

My biggest mistake as a fellow scandinavian tomatoe grower is to start them too early. I started my first batch this year on the 5th of March. A few weeks later then last year, because I run into logistical problems later on. Plants are growing fast and are big but they can't go out yet (during the night). Last year I had around 100 plants. This year it will be more.

Legginess isn't a really big problem usually because you can plant the seedlings just deeper when you transplant them. The extra stem length just goes underneath the soil.

[QUOTE=spuriousmonkey;457388]You would need to measure the temperature under the lights. That's how warm the plants will be and that will decide how fast the physiological processes can run. The warmer, the faster a plant can grow. (which in this case is not good).

Are the plants leggy this year?
When did you start them?

My biggest mistake as a fellow scandinavian tomatoe grower is to start them too early. I started my first batch this year on the 5th of March. A few weeks later then last year, because I run into logistical problems later on. Plants are growing fast and are big but they can't go out yet (during the night). Last year I had around 100 plants. This year it will be more.

Legginess isn't a really big problem usually because you can plant the seedlings just deeper when you transplant them. The extra stem length just goes underneath the soil.[/QUOTE]
Hi fellow grower in Scandinavia! I started my seeds for plants that are going in the greenhouse on the 7th and 8th of March. They're not leggy yet, but I don't want them to get that way. I'm growing my greenhouse tomatoes in containers, so there's a limit to how deep I can plant them. I have a cool room in the cellar, but it's hard to get the temp. under the lights much under 20 degrees, even though it's just over 16 in the room. Nighttime temp. holds at 16. Guess that'll have to do. I'll start my outdoor garden toms on March 20th (the vernal equinox). I'll have about 30 plants, so the logistics will be easier than your 100.

Steve

I been leaving the heat pad on 24/7 for over 6 days now .. sure they are leggy but still waiting for some old seeds to germinate,, cheokee green from renees which are now two seasons old.. I had he same luck with these particular seed pack ordered.. everything else germinated... now I also read somewhere online that even if old seeds germinate,, the plant will not be fruitful as a new seed.. so maybe it is best I discard any that finally do germinate... I don't have enough room or thein my small home garden nor care enough about these seeds/seedlings to find out. As said leggy, I will soon be transplanting them deep in pint sized party cups

I am curious if you folks know at what high temp the seedlings are damaged? I have noticed in my low tunnel it will get over 100 degrees on sunny days in the 60's, that's with the ends closed. I haven't cooked any yet thank goodness but I usually keep one end opened to avoid overly high temps, but a few times I've forgotten to open it back up before I go to work in the morning.

[QUOTE=BigVanVader;462327]I am curious if you folks know at what high temp the seedlings are damaged? I have noticed in my low tunnel it will get over 100 degrees on sunny days in the 60's, that's with the ends closed. I haven't cooked any yet thank goodness but I usually keep one end opened to avoid overly high temps, but a few times I've forgotten to open it back up before I go to work in the morning.[/QUOTE]
say vader, thinking one day retiring down that way.. would you say nc or sc for climate etc,,? how are the bugs and which are the worse to be of concern for plants and animals? do you get sinkholes like fl? would you prefer coastal near the ocean..tia

I use the infrared thermometer to measure the surface temp of the soil. It may or may not be correct, but l figure consistency is more important.