Heat mats needed?

[Meadowlark]

... short but early tomato season. I plant the seeds the last week of January and they will be ready by the last week of February to transplant.

I will take 3-4 dozen of my sungold tomato plants and use 1-2 gallon pots just in case we get a late frost. There are times I can plant on March 1or a couple of weeks later

By late June the nights are to hot and humid for the blossoms to set

Great description of "short but early tomato season" here also.

 

[Oliver Buckle]

Heat mats are essential for maintaining optimal temperatures in plant propagation,

Not really 'essential', though they are very useful. To an oldie like me they are a fairly new thing, we used to put a lightbulb in a box back in the days of tungsten bulbs that warmed up, then put the seed trays on top, or put wet tissue in a margarine tub, put the seeds in, wrap it in a towel, and leave it in the airing cupboard. I am sure there are plenty of other approaches, all you need is somewhere consistently warm, but not too hot.

 

[yardiron]

I've only used heat mats to germinate seads but lately we've had late springs so I've been just seading in cups and culling the seedlings.
Its April 9th here and the temps are back below freezing again so planting is a long way off here. I put my flats out during the warmer daytime hours and bring them in at night till the night temps remain over 60°F. Then they get planted. In a few weeks I'll be thinking about tilling up the garden and getting the stakes and cages ready.