April 11, 2017
Cultivating tomatoes can involve some mystery
A young volunteer at the Fauquier Education Farm.
By Jim Hankins
Very often people have come to believe that heirloom varieties are more flavorful and more desirable in the gardens. The truth is a bit more complicated than that.
Fauquier Education Farm
Tomatoes are the basic staple in most backyard gardens. With just a couple tomato plants, we can often expect a long growing season of continuous harvest. They are easy to grow. They come in an amazing variety of colors, sizes, shapes and, most importantly, a wide array of flavors.
However, there can be a lot of mystery to cultivating tomatoes. Like most human endeavors, the language of gardening can be full of terms that can be bewildering until you learn all the code words. I am fond of saying that ignorance can be cured, it only requires you to admit that you need to learn something.
Before we get closer to that happy day when it is safe and prudent to set our tomato plants out in the garden I want to take a bit of time to explore these tomato code words and make them easy to understand.
Determinate and indeterminate
People have been cultivating tomatoes for thousands of years and, through careful selective breeding, have changed them a great deal from the wild tomato origins in Central and South America. In their native tropics, wild tomatoes are perennials that will happily live for several years.
The terms “determinate” and “indeterminate” are used to describe the expected life cycle of the plant and are very useful in gauging just how big you might expect the mature plant to be.
The indeterminate varieties of tomatoes have held onto some of their native genes. If cultivated in a greenhouse and protected from frost, they will continue to thrive for several years. In our gardens, picking an indeterminate variety means we can expect a plant that is capable of continuous growth until a frost takes it out. These plants can get very large. In our high tunnel at the Fauquier Education Farm, we will tie up our indeterminate tomatoes to the height of 10 feet and they will still keep growing. In the field, we use 6-foot-tall tomato stakes, and our indeterminate varieties will grow to the top and flop over to keep on growing.
The advantage of growing the indeterminate varieties should be fairly obvious: A longer life cycle should yield more fruit. I often speak of the late-season production of different types of tomatoes as being a prime reason for choosing to grow that type.
The best varieties of indeterminate tomatoes will keep producing well when many other tomato plants have given up for the season. Planting indeterminates will not be a guarantee that your plants will survive until the first frost in the fall. Disease is often an important limiting factor. But, you should expect a large plant that will quickly out grow your standard 4-foot-tall tomato cage. These tomatoes will have a big surge of production early in the season, but most of them do slow down significantly later in the summer. They can keep producing, but most often quality and quantity will drop off somewhat.
Most heirloom tomatoes are indeterminate, (don’t worry, we’ll talk about heirlooms and hybrids in the next section) but there are some excellent hybrid indeterminate tomatoes. For the last two years at the Education Farm, we have only planted indeterminate tomatoes. In the 2017 growing season, we will be planting 15 different varieties, both determinate and indeterminate, so you will be able to see for yourself how they are producing in side-by-side field trials.
Determinate tomato varieties have been bred for a smaller plant size and a more concentrated fruit set. What that means is that they will bear (hopefully!) a lot of fruit in a shorter period. But then the plant will die, even protected from frost in a greenhouse. Commercial growers are very careful with labor costs, and tending to huge plants that may be producing fewer tomatoes in late season isn’t really attractive.
There are quite a few excellent determinate varieties for home gardeners that will still give a good long growing season. It’s just important to understand which type you have bought, so you don’t start thinking you’ve done something wrong to cause your tomatoes to give up before September, when your neighbor’s tomatoes are still going strong. Determinate varieties are often bred for greater disease resistance or a long list of other desirable qualities beyond a compact size
Heirloom or hybrid?
There are lots of gardeners and farmers who are very passionate about their tomato production and endlessly seek ways to improve the fruit of their labors. Humans have been carefully breeding and crossbreeding tomatoes for centuries to change the color, size and flavor. More recently, there has been a large focus on creating tomatoes that can be shipped long distances more easily and even creating varieties that make it easier to harvest with machines rather than by hand.
These days, tomatoes are most often talked about as being either heirloom or hybrids. So, it’s important to learn exactly what these terms mean as you select the varieties you want in your garden. It’s also important to note that there are not any genetically modified, or GMO, tomato varieties commercially available. All of these changes in our tomatoes are happening through good plant breeding, not through laboratory manipulation.
Heirloom tomatoes are simply varieties that have been around for a long time. An important quality to all heirloom tomatoes is that they are open pollinated. That means if you plant a patch of Striped German tomatoes away from other varieties that might cross pollinate the plants, then you can save the seeds from those tomatoes and you will get true Striped German tomatoes the next year. Farmers say, “They will breed true.”
Very often people have come to believe that heirloom varieties are more flavorful and more desirable in the gardens. The truth is a bit more complicated than that. Seed companies have been spinning great tales of tomato varieties ever since someone first thought of selling seeds in a packet.
There are quite a few absolutely fantastic heirloom tomatoes available but also even more heirloom varieties that are difficult to grow and just will not produce well in the field. Often heirloom tomatoes can be more sensitive to disease pressure. It is not unusual for many heirloom varieties to produce oddly-shaped, lumpy tomatoes that are prone to cracking and splitting. It is very well worth experimenting with some different varieties to find types that will grow well for you, regardless of the seed companies promises of a bountiful harvest.
The hybrid varieties of tomatoes require human intervention in pollination to produce the seed stock. That means two very different varieties of tomato are cross-bred with one another to produce a hybrid that will take on the strongest qualities of its parents and produce a plant with greater production, or disease resistance. These plants are bred by hand, taking pollen from one parent to fertilize the flower of the second, with people replacing the bees.
These hybrids will not breed true, which means if you save the seed from a Big Beef tomato, you will get a tomato, but it will be different from its parent. In the dog world, if you want a Labradoodle, you breed a Labrador to a Poodle. If you breed a Labradoodle to a Labradoodle, you will get a mutt with much more unpredictable qualities than either parent.
People discovered ages ago that this first generation of hybrids will often be healthier and easier to grow than the parent stock. We call this hybrid vigor, and it is true in both animal and plant breeding. You will often see F1 attached to the name of a plant variety, which means it is a first-generation hybrid that was carefully selected for specific qualities. In the tomato world, these are often called disease resistant varieties, or they were breed to reduce cracking or superior size or more concentrated fruit set.
It is true that some of these tomato varieties were bred of longer shelf life and have resulted in the tasteless, wintertime tomatoes in the grocery store. But that is not true of all hybrid tomatoes. A great many of these F1 hybrid tomatoes have become garden favorites that produce large crops of attractive and very edible fruit. You just won’t be able to save the seeds and expect a true copy of that F1 tomato.
Tomatoes are easy and incredibly rewarding to grow. Those first few BLTs each year made with sun-ripened tomatoes from your own garden are an annual pleasure that I cherish and look forward to for months before the fruit ripens. But the amazing variety of types can become confusing, and each can offer its own challenges and rewards. As I’ve said, this year at the Fauquier Education Farm we will be planting a variety trial of 15 types of tomatoes so the public can see for themselves how these indeterminate, determinate, heirloom and hybrid tomatoes are producing side by side.
We will have a workshop from 6 to 8 p.m. Wednesday, July 12, and invite all interested to come see for themselves. The workshop is free and open to everyone.
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BJ · April 13, 2017 at 8:15 am
Thank you Jim for another wonderful, informative article. The Fauquier Education Farm is in great hands!
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