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Choosing Tomato Varieties: Deciphering Indeterminate, Determinate and Dwarf Growth Habits

By now, your mailboxes are probably recovering from the strain of holding the endless stream of winter seed catalogs. Your eyes are likely red and tired from eyestrain as you flip through the pages. Possibly, your brain is hurting from sorting through the possibilities and making decisions. It reminds me my dilemma when deciding which music to listen to. My musical tastes are broad; I love music, and listen to it pretty much all day long. But sometimes trying to decide what to listen to brings about mental paralysis.

With thousands of choices of tomatoes available to tomato growers (especially if starting from seeds, rather than seedlings), a few simple basic considerations can provide some guidelines for narrowing the field, helping you make choices of what will appear in your garden this coming season.

Let’s start with one of the most basic attribute of a particular tomato variety – its growth habit. (In the next blog post, I will touch upon an equally important set of attributes – hybrid, heirloom and open pollinated.)

Indeterminate Tomato Varieties

Indeterminate tomatoes will be familiar to those who grapple annually with wild, tall, out of control plants that take up lots and lots of space. The central growing stem expands outward (or upward, if you tie it to a vertical stake or trellis) indefinitely – until you prune it at a particular height, or it is nibbled by a critter, or, most often, the plant dies at the end of the season from frost or disease.

Another characteristic of indeterminate tomatoes is the formation of side shoots or suckers at every joint between the leaf shaft and stem. Each sucker itself produces more suckers. This is what creates the great width of an indeterminate variety, which when combined with the infinite upward growth of the fruiting stems, create single plant jungles, or multiple plant hedges.

Example Varieties:

Hybrids: 'Better Boy', 'Lemon Boy', 'Big Beef', 'Sun Gold', 'Sweet Million'.

Open pollenated and heirlooms: 'Cherokee Purple', 'Brandywine', 'Lillian’s Yellow Heirloom', 'Kellogg’s Breakfast'

Advantages of Indeterminate Tomatoes

Most tomato varieties are indeterminate; the vast majority of heirloom varieties certainly are.  The selection of indeterminate tomato varieties is therefore huge – a blessing in terms of options and a curse in terms of making decisions.

The optimum ratio of foliage to fruit provides indeterminate tomatoes the potential for the very best flavors. Plenty of foliage in relation to the number of tomatoes means lots of photosynthesis and other necessary processes for excellent flavor development. This doesn’t mean that all indeterminate varieties are delicious, but most flavor favorites seem to be in this category.

Tall, wide and spreading plants mean potentially heavy yields, depending upon how they are grown.

Indeterminate varieties produce fruit continually until killed by frost or disease, meaning gradual but long duration harvests.

Disadvantages

For most gardeners that don’t have infinite space and possible diseases in their soil, some sort of control is necessary – typically staking, trellising or caging. A sprawling indeterminate tomato plant on garden soil is an invitation for disease.

It isn’t necessarily a disadvantage but a consideration – removing or leaving suckers is a key decision for those growing indeterminate tomatoes. Those that cage don’t typically prune at all, and potential yields are enormous. Removal of all suckers, leaving just the central growing stem, will reduce yields and may lead to sun scald on tomatoes that are exposed to direct sun. A happy medium – letting two suckers develop, meaning 3 main fruiting stems – is my current practice, and serves me well.

For those who grow in containers, a capacity of 10 gallons is the minimum for reasonable yields of tomatoes.

Determinate Tomato Varieties

Determinate tomato varieties have a genetic characteristic that limits growth and tends to ripen the crop in a fairly concentrated time span. The gene for this type of growth, also known as self-topping, wasn’t discovered until the 1920s. There are very few true determinate heirlooms for this reason – the growth habit simply hasn’t been around for all that long.

Because so many tomatoes are often formed on plants with such reduced height and width, the fruit to foliage ratio is far higher than for that of indeterminate or dwarf varieties. This seems to be why flavors of most determinate tomatoes are less intense; think Roma, probably not the first tomato you would reach for to get the best fresh tomato eating experience.

Example Varieties:

'Roma', 'Martino’s Roma', 'Sophie’s Choice', 'Southern Night', 'Taxi'

Advantages of Determinate Tomatoes

Determinate tomato varieties are perfect for container gardening and short stakes and cages. They don’t need to be pruned at all; in fact, removing suckers significantly reduces the yield. A five gallon capacity container will grow a determinate variety very well.

Since the tomatoes on determinate varieties tend to ripen within a short time frame, they are perfect for preserving; grow a few Roma types and get ready to do lots of canning once the fruit all start to ripen.

Disadvantages

There are far fewer determinate varieties available to choose from, spanning a limited fruit size and shape and color range.

The flavors of determinate varieties just don’t seem to have the sparkling intensity and complexity of indeterminate or dwarf varieties.

Determinate tomatoes are not suitable for those who desire a long harvest window, since they tend to ripen their fruit in a short time span. This makes them a good choice for processing, such as canning, when a large quantity of ripe tomatoes make the work worthwhile.

Dwarf Tomato Varieties

Dwarf tomato varieties are the least familiar of the three major growth habits. Due to the recent releases from the Dwarf Tomato Breeding Project that I co-lead, this is changing rapidly, and space-challenged gardeners can now replicate the “heirloom tomato experience” by using exclusively dwarfs.

Though known in America since the 1850s, only a few Dwarf tomato varieties were in existence until very recently. Unique because of their very thick central stem, dark green crinkly foliage (also known as “rugose”), continuous fruiting and short stature, I consider Dwarf tomatoes be similar in many ways to indeterminate types, but they grow vertically at only about half of the rate. They need no pruning, grow happily in containers as small as 5 gallon capacity, and are the perfect tomato type for those familiar wire cone-shaped 4 foot cages.

Example Dwarf Tomato Varieties:

'New Big Dwarf', 'Dwarf Champion', 'Lime Green Salad', 'Dwarf Wild Fred', 'Dwarf Sweet Sue', 'Summertime Green'

Advantages of Dwarf Varieties

Because they fruit gradually but continuously until killed by frost or disease, like indeterminate varieties, the ratio of foliage to fruit is not nearly as out of whack as with determinate types. There is sufficient photosynthesis in the ample foliage to allow for the very best of flavors; we’ve found that many of our dwarfs mirror indeterminate types in flavor excellence.

The short stature allows for closer planting, and because they don’t need tall stakes or trellises, they are perfect varieties to bring the joy of tomatoes via decks, patios or (in my case), driveways.

Disadvantages of Dwarf Tomatoes

Though great progress has been made recently on expanding the available options, there are still less than 100 dwarf varieties for gardeners to choose from. Yet, among the varieties are large fruited, delicious tomatoes in just about all possible colors.

Because many of the new dwarf varieties are so recent, availability of many of them is limited, but increasing yearly.

With plants at half the height of indeterminate varieties, the yield of dwarf types are lower; closer spacing due to the compact size can help compensate, howerver.

My own gardens, despite growing all of my tomatoes on my deck or in my driveway, are typically a mix of indeterminate and dwarf types. Before the Dwarf Tomato Breeding project began in 2005, the vast majority of the tomatoes I grew were indeterminate. A sure sign of how successful our project is lies in my move toward growing mostly dwarfs.

We are simply very fortunate to have such a wonderful selection of tomatoes to choose from. Having a clear idea of the differences in growth habit will help guide you to success. In my next blog, I will share my guidance and views on the terms hybrid, heirloom and open-pollinated when describing tomato varieties.

Craig Lehoullier is an heirloom tomato expert (and amateur plant breeder). He currently is on book promotion tour for Epic Tomatoes, setting upcoming tomato workshop events, updating his website and blog, devising a totally new, all-heirloom weekly podcast, shooting a tomato know-how video series and pondering topics for future books. He is co-leading the Dwarf Tomato breeding project to put 36 new dwarf-growing, open-pollinated tomatoes in the hands of various small seed companies. Read all of his MOTHER EARTH NEWS posts here.


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craig
2/6/2016 9:26:45 AM

FrancieG - thanks for your kind words. My intent with my blogs is to take tomato enthusiasts on the journey with me, but focus on those key decisions and techniques that will lead to an enjoyable experience. Ask anything, any time!


francieg
2/6/2016 5:55:43 AM

Thank you for this information. Now that I have a large yard I plan to plant things every year, but after reading so much stuff I get totally confused and overwhelmed that I get nothing done. Most articles have "too many words" and I close them before getting to the end, but this is information I can actually use.