How cold, how hot?

[JerryL]

I’ll be putting some seedlings in the green house soon and had a question about temps.
What temperatures should I try to maintain? I’m thinking 40 on the cold side and 90 on the high side.
Anyone have 2 cents to contribute?

[KarenO]

I try for a little less of a swing, maintaining a more even keel would be better. Most things can tolerate either of those extremes for a while but don't like the wide variation. If you have the ability to keep it between 50 and 80 that would be better. I am more used to centigrade measurements so give or take a few degrees. you will have micro climates hotter and colder within your greenhouse as well so measuring air temperature in the center would be more of an average. hotter up high and in direct sun, cooler down low and in the shade so that helps to determine where to place your trays. It's all an imprecise balancing act in my greenhouse and every greenhouse is different. Requires a lot of attention and monitoring in my area especially in early spring when I have to heat it.
KarenO

[Worth1]

50 to 75 or 80 if you can keep them from 50 to 75 it would be better.

Worth

[JerryL]

Thanks for the input.

[Patihum]

I've got mine in a large greenhouse that runs between 55 and 62 but I'm looking to hold them until the middle of April or just a little later. They're on the morning sun side which does make a difference in the amount of heat they get from the sun thru the sides. I've found that the cooler temps produce a stockier plant.

[AKmark]

I keep mine between 60-80, but sometimes I cannot keep them from getting hotter.

[amideutch]

I've found that the cooler temps produce a stockier plant.

This is one of the advantages of doing the "Cold Treatment" to seedlings.

Ami

[Doug9345]

I'm going to be a devil's advocate and ask does having a stockier plant translating into any measurable difference in the field? Does said seedling produce early, more, or better tomatoes. I can see if you are selling them you might be able to get more for them or sell more of them, but if I'm growing my own tomato plants for myself what advantage does it have?

If it's a question of energy use in a greenhouse at least show me the calculations and even better recorded weather and fuel use.

[Patihum]

Originally Posted by Doug9345

I'm going to be a devil's advocate and ask does having a stockier plant translating into any measurable difference in the field? Does said seedling produce early, more, or better tomatoes. I can see if you are selling them you might be able to get more for them or sell more of them, but if I'm growing my own tomato plants for myself what advantage does it have?

If it's a question of energy use in a greenhouse at least show me the calculations and even better recorded weather and fuel use.

I've found that the stockier plants are a lot less likely to suffer much or even any transplant shock when put out and in that regard they are actively growing in a shorter amount of time rather than recovering from being planted. Do you end up with earlier tomatoes? You're talking about maybe only a week - no great difference - but with the heat we get here I want every tomato I can get before they stop producing. Also being a little larger means they are better able to withstand any damage if the bugs show up early on.