Tomato Seed Starting Temps

[jmsieglaff]

What air temperature do you start your tomato seeds?

I see a lot about heat mats, etc. but I've always started on top of our kitchen fridge which is 68-70F depending on the day. This year, like most, for each variety first seed emergence ranged from 5 to 8 days.

[joseph]

I start tomatoes under my standard seed starting conditions which are not listed in the poll:

85F for 16 hours per day coinciding with fluorescent lighting, followed by 8 hours per day at ~60F in darkness.

Heat is provided by a small temperature-controlled fan-driven air heater.

[RJGlew]

Taken from Johnny's.

[ginger2778]

Mine are started in late August or early September, in the open air, no heat mat needed. Second batch started mid December for a January plant out. Reversed season here.

Marsha

[jmsieglaff]

It will be interesting to see the distribution of temps from folks here. I've never thought about the Florida tomato seasons--I suppose summer would be a disease fest with dewpoints constantly in the mid 70s.

[RayR]

The question that was asked is "What air temperature do you start your tomato seeds?", not what soil temperature do you start your tomato seeds?
Two entirely different things, soil temperature is the important factor in germination.

[ginger2778]

Originally Posted by jmsieglaff

It will be interesting to see the distribution of temps from folks here. I've never thought about the Florida tomato seasons--I suppose summer would be a disease fest with dewpoints constantly in the mid 70s.

Pretty much.
Never get fruit to set except maybe heat tolerant types.
Marsha

[jmsieglaff]

Originally Posted by RayR

The question that was asked is "What air temperature do you start your tomato seeds?", not what soil temperature do you start your tomato seeds?
Two entirely different things, soil temperature is the important factor in germination.

Agreed, but I don't take my soil temperature of my seed starting mix, that's why I asked about air temp.

[RayR]

Originally Posted by jmsieglaff

Agreed, but I don't take my soil temperature of my seed starting mix, that's why I asked about air temp.

Air temperature is not a good indication of soil temperature especially when using bottom heat. An inexpensive analog or digital kitchen or bar thermometer with a steel probe is a handy thing to have around for quickly checking soil temperature.

[Doug9345]

I couldn't give you more than an guesstimate on air temperature. Soil temperature I generally know as it is much more stable than air temperature. For example I have my peppers setting out side. The general air temperature is somewhere in the low to mid 60's °F maybe a little higher. Given that it is partially sunny but with a breeze what is the air temperature that the seedlings are actually experiencing.

I suspect that many of the differences that we see between two plants that are supposedly grown in the same conditions aren't actually in the same conditions. I can't do it this year, but I'm thinking about building some instrumentation to see just how much a field varies from one plant to the next and even across the same plant

[KarenO]

room temp in my kitchen which is where I start my seeds ranges about 68-72 F =about 19-20 Celcius.
Most of my seeds I germinate in the house just at room temp without bottom heat. I have a greenhouse but I find better germination for most things at the constant temp in the house rather than the fairly big day-night temp fluctuations in my greenhouse. Same with starting cuttings, I find they take better in the house under controlled and constant room temperature without wide fluctuations.
Fresh, good tomato seed does not require bottom heat to germinate although you may speed things up by a couple of days there will be no appreciable difference in a week's time. Don't think it is necessary to purchase a heat mat just for starting tomatoes. Some other seeds, hot peppers for example do germinate better with bottom heat but in all cases care must be taken as to proper controlled temperature as the risk of killing your seed with overheating is perhaps higher than any benefit of faster germination from using a heat mat.
KarenO

[Barbee]

I just did one flat of tomatoes this year. I have a germination chamber with a heat mat inside for starting hot peppers and giant watermelons. Temps in the germination chamber range from 85-99 depending on how tight I close it up and what Im germinating. I set the tomato flat with a dome on top of the germ chamber. Temps averaged 78-80 degrees.

I have also germinated tomatoes many times at room temp and it does fine. Just take a bit longer.

Note* I noticed less problems with helmut head this year using gentle heat to germinate. Coincidence?

[MrBig46]

75 °F.
Vladimír

[PA_Julia]

I start my seeds in a Jiffy brand greenhouse tray but instead of putting the clear plastic lid over the top of the tray I place it on a heating mat in a small plastic tub.

I keep the temperature of the mat at approx 85 to 90 F.

I see germination of around half my seeds in approx. three days with the remainder ranging from four to seven days.

Here is a photo of my seed starting setup.

[Randall]

This has always worked like a charm for me:

http://tomclothier.hort.net/page11.html