The Heirloom thing VS Modern VS Hybrid.... The line between "heirloom" and modern has become so blurred that it is almost pointless to make the designation! Many very old varieties have been resurrected and all the fun breeding work is being done with them, along with other genetic pools. It used to be "heirloom" meant colors, sizes, shapes and (good) flavors not found in the super market. Modern meant red, round, 5 oz. tasteless hunks of concrete. Not anymore! About the only thing I can say about "modern" V.S. "heirloom" is the year they were first released or noted in historical records. There is also a general feeling that "heirloom" means delicious and wonderful. Not so. I have tasted many heirloom varieties and some taste like Bat piss. Many of the best right now are varieties are ones that have been released with in the past decade. This is not only an issue of flavor but, in addition, beauty. This also includes hybrid (F-1) varieties.
Speaking of hybrids... People have gotten the wrong notion about hybrids thanks to the hippy-nerds who spend too much time on Facebook; they do not really understand the concept. In the Tomato world, all this means is a company has two (secret!) strains of Tomatos which they manually cross each year to produce the hybrid. This hybrid displays a consistent set of desired traits each year. It is a lot of work for these companies. See, Tomatos, as a rule, are inbred by natures design. Unlike most plants and animals, tomatos do not exhibit inbreeding decline. In order to cross two strains of tomatos, it has to be done by hand, part of the flower must be removed. Look up the process online. Pretty time consuming! The Hippy-nerds scream "Don't buy hybrids! They are the work of Satan and big agribusiness! You can't save and plant the seeds from these tomatos!" They act like the seed from hybrids is some weird genetic mutation Dr. Frankenstein created.. The fact is, you most certainly can plant the seeds. You just wont get the exact Tomato that you took the seed from. This is called genetic desegregation- there were two distinct parent plants involved with the creation of the original hybrid. For the next few generations, you will see variability in the seedlings. After about 5 generations, you would notice each generation getting more and more predictable (this is the natural self pollination/inbreeding I referred to). At that point, you are creating a new strain of tomato if you were selecting for a certain trait. We actually have a number of named strains now that descend from famous hybrids. The main take-away here is that hybrids often are tougher and more disease resistant than their open pollinated counterparts. That is why they exist.
And then there is the GMO thing. Ugh. Forget about it. It is a clever marketing gimmick from retail seed companies. GMO seed is proprietary, very expensive and has specific uses. It just isn't found in garden variety tomatos or other species we plant in our gardens. It never was. Seed companies like to trumpet that they do not sell GMO seed- as if they did something special for you. They are just capitalizing on fears the hippy-nerds foster.
Throw away all preconceived notions of what makes a good Tomato. The only way you will ever find YOUR perfect Tomato is to try new ones each year! Isn't that what makes growing a garden fun anyway?
A couple quick notes on culture. If you have problems with blossom end rot, be sure you are using a pelleted lime product. It is cheap. I usually work in a few tablespoons in at planting time being careful not to concentrate it to much around the immediate root area. Later on at about bloom time, I will do a little side dressing with the same product. Our soils in East Texas and NW Louisiana tend to be deficient in calcium- one of the triggers of this problem. Certain strains of Tomatoes are often more susceptible to blossom end rot. The other reason, along with calcium deficiency, is erratic watering- something I am quite guilty of. In years with good rain, blossom end rot is not much of a problem.
If you are using a liquid fertilizer like, say, MiracleGro, you MUST use it weekly. So often I ask people who are having poor growth if they fertilize- they say "Yes". When I question with what and how often, they will proudly say "MiracleGro! two times last Summer!" Weekly. No exceptions. Otherwise use a standard 13-13-13 or the like. BTW..many people do not know that liquid fertilizers (like MiracleGro) can be absorbed thru the leaves. Just make sure you are following the dilution directions correctly. This is even more important if you are growing tomatos in a pot. They are heavy feeders. Make sure you are meeting the requirements. Just as a side bar- if you choose to grow tomatos in a pot, stay away from the big Beefsteak types. It just isn't worth the effort. Instead, the smaller fruited varieties do much better. Cherry tomatos produce fantastically in containers!
One thing I would like to touch on- you all know the Bonnie Racks at all the Walmart stores etc. selling tomatos (at outrageous prices- getting near $4.00 bucks a plant!). Those plants have often been treated with growth regulators. This is a common practice among large growers. Great for them, not so much for you. What these chemicals do is retard (temporarily) the growth of plants. Adds a lot of "shelf life" and, in addition, causes the plant to take on a very deep green color. They look great but there is a waiting period for this stuff to wear off. You need your plants to hit the ground running- we have to beat the heat for pollination here in the deep South. My plants are never treated with growth regulators.
Now, go click on the color tabs! Find your new best Tomato!