You're not going to be able to keep them inside that long. Tomatoes don't like it that long. But to help, when you plant up, bury most of the stem. That will make the plant work on roots. Also cool temps slow down growth so grow them in a cooler room or cold frame.

When you put them out use concrete reinforcing wire cages that are wrapped in plastic to protect them. (Don't forget to stake the cage down as it makes a heck of a sail). Then when the weather warms up, take the plastic off.

I think you are okay with starting your tomatoes when you did. Just don't over-fertilize to get rapid growth; keep them in appropriately sized containers (you may have to transplant them twice, once into larger cells and then into quart pots); and if you simply MUST put some of them out before April, you can protect them from frost with a cover (I use big black plastic pots). Check with your county extension agent to see when the usual last frost date is for your area. For us here in Central Texas, it's March 15. You're going to have a magnificent tomato harvest!

I move mine to larger pots as needed and keep them on the patio. If it gets below 40 degrees, I move them inside the back door. Then once it is above 40 I take them back out. Temps 40 and below will hurt the plants even if they don't freeze. I learned this from my Daddy, who was in the tomatoes business.
So I move them in and out a lot until night temps are ok.

Plantmaven, what kind did your Daddy plant? What kind of business did he have - selling to big companies or to the public? Interesting! :)

I started my seeds last week too. I grow a little garden in my backyard. My thought is that to grow tomatos in Texas, you have to be a little bit of a gambler. I put my plants in the ground in mid February, it makes me feel alive :). Sometimes I win and sometime I lose. But I always start a few more transplants than I need in case the frost gets me.

I've planted a ton of seeds. I was given 8 different kinds of tomatoes in a seed trade in 2007 plus 3 kinds that I ordered this year. I wasn't sure the older seeds would sprout but they all came up so I have lots of tomatoes and, if all goes well will spread the extra plants around to family and friends. I don't have enough room to plant all of them. :-o

Daddy did not grow them. He bought them by the whole field and sold them to the packing companies.
Oh my, that was a long time ago. He is now 90 yrs.

My Papa grew and shipped tomatoes out of East Texas some 50 years ago. He'd build numerous mini bonfires in and around the the fields when the frost came.

He grew them, packed them and shipped them all over the county. I'm told they were quite popular in Chicago. That was back before there were the super thick walled tomatoes they grow today and sell in the grocery stores.

I agree, tomatoes today sure are different from the ones 50 years ago.
I remember Daddy going to Jacksonville, TX for tomatoes.

By the way..a day late happy birthday.

Thanks, I spent it with the family.

Papa lived in Frankston, 20 minutes west of Jacksonville. That East Texas soil can grow just about everything.