Just getting first leaves at a month is too slow. Assuming they are getting enough light (this will be obvious due to pale leggy plants), my guess would be it is an over watering problem rather than lack of fertilizer. The most important rule for starting tomatoes is when in doubt, don't water.

They are a vibrant green and not leggy at all (yay!). I keep the two fluorescent growing lights 1.5 inches from the seedlings and they're on for 18 hours/day. They also have a light fan blowing on them for a few hours every day.

I've been only watering when the mix gets completely dry.

It just doesn't make sense that my beefmasters are growing so vogorously while the brandywine is lagging. :(

you need too give more imfo. what is your soil, what are your temps, pot size, are they on a warming mat?

You cannot compare different varieties with any degree of accuracy. That said, Brandywine is a late season variety so one would expect slow growth from it.

Dave

@terrybull

I have them in organic Seed Starting Jiffy Mix. The soil temperature is consistently 65-70 degrees. They are not on a warming mat.

@Dave

That's what I've been hoping. I did find that Brandywine was a slow grower so I'm keeping my fingers crossed!

Thanks everyone!

With Jiffy mix, I wouldn't let it dry completely before watering again. Just my two cents.