determinate – greenupside

A lot of gardeners wonder if there is a big difference between determinate and indeterminate tomatoes. As it turns out, there are several key differences, each of which will affect the way you care for the plants. So, what is the difference between determinate and indeterminate tomatoes? Determinate tomatoes are shorter, growing to heights of 4 to 6 feet, while indeterminate tomatoes grow to 7 feet or taller. Determinate tomatoes produce fruit during a much shorter time window of 4 to 5 weeks, compared to 2 to 3 months or longer for indeterminate tomatoes. Finally, determinate tomatoes do not need tall stakes for support, as indeterminate tomatoes do. Of course, the way you care for your tomato plants will depend on which types you are growing. In this article, we’ll talk about the differences between determinate and indeterminate tomatoes. We’ll also get into how you can tell them apart if you don’t remember what you planted, or if you get volunteer tomato plants. Let’s get started. Difference between Determinate and Indeterminate Tomatoes The key differences between determinate and indeterminate tomatoes are: HeightTiming of fruit appearanceNeed for SupportNeed for Pruning The following table gives a summary of the differences between the two types. TraitDeterminateIndeterminateMaximumHeight4-6 feet6-7 feetor moreFruitTiming4-5 weekwindow2-3 monthwindow(to frost)Supportcage orshort staketrellis ortall stakePruningnotneededprune tocontrolheightVarietiesCelebrityRomaetc.Sweet 100Brandywineetc.This table compares the traits of determinate and indeterminate tomato varieties. What Are Determinate Tomatoes? Determinate tomatoes grow to a height of only 4 to 6 feet. Once they reach this height, they stop growing and produce a terminal end at the top of the plant. Determinate tomatoes have what is called a “bush” growth habit. That is, they start off by growing taller (vertical growth), later producing side shoots to grow outward (horizontal or sideways growth). Determinate tomatoes only produce fruit during a limited window of time, bearing tomatoes for about 4 to 5 weeks during the growing season. After producing fruit, determinate tomato plants will stop growing and the plant’s life cycle will end. Determinate tomato varieties produce fruit for a short time window (4 to 5 weeks) compared to indeterminate tomato varieties (2 to 3 months). Due to their smaller size, determinate tomatoes are ideal for container planting. You might even be able to grow them indoors if you have a room that gets enough sunlight (tomato plants need at least 6 to 8 hours of sunlight per day). Some famous determinate tomato varieties include: Celebrity – these plants produce medium to large red fruit (7 to 8 ounces) about 65 days after planting. They only grow 3 to 4 feet tall. You can learn more about Celebrity tomatoes on the Bonnie Plants website.Roma – a type of plum tomato, these are used for producing tomato sauce or paste for pizzas and pasta. The fruit is only 3 inches long, but takes 73 to 80 days after planting to reach maturity. The plant itself can grow 4 to 6 feet tall. You can learn more about Roma tomatoes on the Bonnie Plants website. Celebrity tomatoes don't grow very tall, but they produce nice, red, medium-sized fruit.Image from: https://commons.wikimedia.org/wiki/File:Celebrity-fruit.jpg Do Determinate Tomatoes Need Cages? Determinate tomatoes need cages to keep them neat as they grow taller. Cages also provide support, which prevents tomato plants from falling over. If you don’t support tomato plants somehow, they will revert back to their natural growth habit. That is, they will fall over when they get tall enough, and then crawl along the ground as they continue growing. When tomato plants grow along the ground, their leaves and vines get wet more often and stay wet for much longer. Wet leaves and vines invite fungus and diseases into your plants. Also, any fruit that rests on the ground will rot faster, due to contact with the soil and moisture from rain or watering. Do Determinate Tomatoes Need to be Staked? Determinate tomatoes do not need stakes, since they don’t grow quite as tall as indeterminate tomatoes. However, you can still use stakes for support as an alternative to cages. You can probably get away with shorter stakes to provide support for determinate tomatoes. I would suggest using a stake that is about 6 feet tall. That way, you can drive about 1 foot of the stake into the ground to keep it standing securely. This will leave 5 feet of stake for the tomato plant to climb up as it grows. Do Determinate Tomatoes Need to be Pruned? Determinate tomato plants do not need to be pruned. Remember that they stop growing at a certain point, which means that they won’t become too tall or overgrow like indeterminate tomatoes will. In fact, pruning determinate tomato plants can result in less fruit during the season. You can use pruning shears to remove the lower tomato branches to avoid disease, but taking off to many will reduce fruit production. However, there is one good reason for pruning tomato plants. Pruning off the low-hanging branches will remove leaves that would otherwise catch dirty water from rain splashing in the soil. This will prevent the spread of disease in your garden. If you have had an issue with blight in the past, pruning a few of the lower branches on your tomato plant might be a good idea. You can learn more about how to prune tomato plants in this article from the University of New Hampshire Extension. How Long Will Determinate Tomatoes Produce? Determinate tomatoes will produce fruit for a period of 4 to 5 weeks, and then they will be done for the season. This makes them a good choice for preserving, since you will want most of the fruit to mature around the same time for canning. Of course, you might want a longer harvest window for your tomatoes. In that case, you can stagger your planting of determinate tomatoes. For example, you could plant one crop of determinate tomatoes 3 to 4 weeks after the first crop is planted. Then, as the first crop is finishing up fruit production, the second crop will just be starting to produce. However, you will need to pay attention to a couple of things: The length of the growing season (frost dates)The days to maturity (how long it takes the plant to produce fruit) In an area with a short growing season (such as the state of Vermont in the U.S.), there might not be time to grow multiple tomato crops. This is especially true for tomato varieties that take a long time to mature. Watch out for frost in the spring and fall, especially in cold areas with a short growing season. You can check the frost dates (spring and fall) in your area with this frost date calculator from the Old Farmer’s Almanac. You will want to wait until danger of a spring frost has passed until planting your tomatoes. On the other hand, you need to make sure there is enough time for the plant to reach maturity before a fall frost arrives. Usually, you can find the days to maturity printed on the seed packet or on the container that tomato transplants were packaged in. For example, let’s say that you are growing Fourth of July tomatoes, such as these ones from Burpee. They take 49 days to maturity (7 weeks). Remember that you want to harvest tomatoes for another 4 to 5 weeks after maturity. That means you should plant your tomatoes at least 11 to 12 weeks before the last frost date in your area. What Are Indeterminate Tomatoes? Indeterminate tomatoes grow to a height of 6 to 7 feet or more. They do not stop growing until frost ends the growing season for the year. Indeterminate tomatoes have what is called a “vining” growth habit. That is, they get taller and taller, climbing a stake or trellis as they grow, without getting too wide. Indeterminate tomatoes produce fruit more than once, for as long as they can survive (usually up until the first fall frost) and as long as pollination occurs. Due to their tall size, indeterminate tomatoes are better suited for outdoor growing, rather than indoors or in containers. They will need stakes or trellises for support, due to the heights they can reach. You can learn more about indeterminate tomatoes in this article from the University of California. Some famous indeterminate tomato varieties include: Sweet 100 – these sweet cherry tomatoes ripen to a bright red color, weighing only 1 ounce but maturing in 70 days after planting. You really can get 100 or more of these tiny tomatoes on 1 plant! You can learn more about Super Sweet 100 tomatoes on the Burpee website.Brandywine – these large pink tomatoes can weigh up to 14 ounces, but they take 85 days to mature. You can learn more about Brandywine tomatoes on the Burpee website. Brandywine tomatoes are large and pink, but take some time (85 days) to mature. You can find many more indeterminate tomato varieties (along with a printable list of 22 types) in my article here. Do Indeterminate Tomatoes Need Cages? No, indeterminate tomatoes do not need cages for support. Stakes or trellises will work fine to support them. (Cages are better for indeterminate tomatoes). In fact, stakes and trellises are much better suited for supporting indeterminate tomatoes. They can support taller plants, due to their extra height. You can learn more about supporting tomato plants with stakes (and other methods) in my article here. You can also learn about what to use for tomato ties in my article here. Do Indeterminate Tomatoes Need to be Pruned? Indeterminate tomatoes do not need to be pruned. However, pruning them will keep them at a reasonable height, especially if they get too tall and outgrow their supports (stakes or cages). In that case, the plant could fall over and the stem might break. You can still save a tomato plant with a broken stem, though. Also, remember that pruning the low-hanging branches will help to control disease caused by water that splashes up from the soil. How Much Space Do Indeterminate Tomatoes Need? The space between indeterminate tomato plants will depend on the method of support that you use. According to Iowa State University, you should use the following spacing for indeterminate tomato plants: Staked: 18 to 24 inches (1.5 to 2 feet) apart, since they will tend to grow up the stake rather than getting wider.Caged: 30 to 36 (2.5 to 3 feet) apart, since they will tend to grow a little wider to fill the cage.Crawling on Ground (no support): 36 to 48 inches (3 to 4 feet) apart, since plants that cannot grow upward will take up more space on the ground. Regardless of the support used for your tomato plants, rows should be 4 feet apart. This leaves enough room for the plants to grow, and for you to make your way between rows to water, fertilize, pull weeds, prune branches, and harvest fruit. How Long Will Indeterminate Tomatoes Produce? According to Iowa State University, indeterminate tomatoes can produce over a 2 or 3 month period, since they continue growing until frost ends the season. (My experience confirms this!) How to Tell Determinate From Indeterminate Tomatoes Sometimes you cannot remember what you planted in your garden, so you don’t know whether the tomatoes are determinate or indeterminate. It is also possible that seeds from last year sprouted, took root, and grew into volunteer tomato plants. Either way, it’s nice to know how to tell the two types of tomatoes apart. However, you might need to wait until later in the season to find out. First, remember that determinate tomato varieties ripen earlier (fewer days to maturity). So, the fruit on determinate tomato plants will often be the first ones to appear, assuming everything was planted at the same time. Also, remember that determinate tomato varieties stop growing once they reach a certain height (usually between 4 and 6 feet). If your tomato plant is growing to the moon (7 feet tall or more), it is probably indeterminate. Another sign of a determinate tomato plant: one that produces all of its fruit and then stops growing and producing long before the first fall frost. If your tomato plants stops producing fruit after 4 to 5 weeks, long before the first fall frost, then it is probably determinate. It is also worth mentioning that there is something called a semi-determinate tomato. For example, Celebrity tomatoes are semi-determinate. This means that they grow to a fixed height (like determinate tomatoes), but they keep producing fruit until frost ends the season (like indeterminate tomatoes). Conclusion Now you know how to tell the difference between determinate and indeterminate tomatoes. You also have an idea of which tomato varieties fall into each category. If you are preparing for the upcoming gardening season, check out my article on what to do before planting tomatoes. You might also want to read my article on why tomatoes grow slowly (and how to fix it). I hope you found this article helpful. If so, please share it with someone who can use the information. If you want to read some of my most popular posts, check out the “Best of GreenUpSide” page here. Enjoy! ~Jonathon