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  • Writer's pictureBath Garden Center

How To Grow Tomatoes in Colorado

Tomatoes are quite possibly the most common plant to be found in gardens across the country. They are extremely popular for their bright and delicious fruit that can be used in countless recipes, from fresh salads to soups and more. However, despite their commonality, tomatoes can be particular in their growing needs and can pose some difficulties for novice gardeners. If you have a tomato garden or are thinking about growing tomatoes, here is some information that we hope will be helpful in leading you to success.

Grow Tomatoes

11 Steps On How To Grow Your Own Tomatoes

1. Site Selection for Growing Tomatoes

Site selection is incredibly important for growing tomatoes. Tomatoes should be grown in areas that receive full sun. South or western facing areas are preferable, as 6 hours of sunlight is generally the minimum requirement for successful tomato growing. Depending on personal circumstances and varieties, tomatoes can be grown in traditional gardens, containers, raised garden beds, hanging gardens, and more. For some fun ideas on how to have a garden with limited space, check out our blog on small space gardening!

2. Amending the Soil

Tomatoes prefer slightly acidic soil with a pH of about 6 to 6.8 (7 being neutral). Colorado soils that have never been amended are typically around 8.5. Amending the soil with mushroom compost or sheep and peat is recommended to reach a more acidic and favorable pH level. Work 3-4 inches of the chosen soil amendment into 4-6 inches of existing soil to improve soil properties.

pH scale

3. Tomato Variety Selection

Depending on whether you are growing in containers, raised beds, or in a traditional garden, you will want to select varieties that are suitable for the amount of space you have. Tomatoes generally require much more space than you would think, so if you have limited space, larger varieties will not be your best choice. Smaller versus larger varieties of tomatoes will be labeled as "determinate" or "indeterminate," meaning one grows to a determined size and usually produces all its fruit at once, and the other does not have a determined size and will continue to increase in size and produce fruit as long as the weather is warm. Tomato plants that are good for containers or raised garden beds may also have "bush" or "container" in the name.

4. Heirloom vs. Hybrid Tomatoes

"Heirloom" indicates that the seeds are openly pollinated, meaning that pollination relies on natural forces such as birds, insects, or wind. The seeds collected produce plants that resemble the parent plant. Heirloom tomatoes generally are the original species of tomatoes that have been grown for generations. "Hybrid" indicates that the seeds were crossbred from 2 or more parents. These types of tomatoes are usually bred for the purpose of producing large harvests. Both types of tomatoes have their pros and cons, so it is completely up to you to decide what you value most.

Pros and Cons of Heirloom Tomatoes

Pros: Better flavor, more nutritious, and you can save the seeds to replant in subsequent years.

Cons: Less disease resistant, produce smaller yields, and have less predictable harvests.

Pros and Cons of Hybrid Tomatoes

Pros: Easier to grow, grow faster, adapt better to stressors, produce larger fruit & higher yields, have better disease resistance, and have a longer shelf life.

Cons: More expensive, less nutritious, less tasty than heirlooms, and saving hybrid seeds is usually not practical as the seeds will not grow a plant resembling the parent plant.

5. Planting Tomatoes

A safe bet for planting is to wait until after the average last frost date. For Northern Colorado and the Front Range, this is usually around the beginning of May or after Mother's Day. Typically, when planting your tomato starts, you want to plant them deep enough to cover the stem up to the plant’s first set of leaves. Roots will begin to grow along the buried stem, which will help to increase the plants’ strength and vigor. Be sure to keep an eye on the weather and cover your tomato plants with frost cloth if temperatures are forecasted to drop below 40 degrees at night!

Planting Tomatoes

6. Spacing Tomato Plants

Providing your tomato plants with adequate space will be very important to ensure that they are able to grow strong and healthy. Indeterminate varieties will take up a lot more room and will need much more space than other varieties. Larger varieties of tomato plants can require as much as 36 inches of space between them. Spacing tomato plants any closer than 24 inches will reduce airflow and circulation, increasing the risk for harmful fungus and disease to affect your plants. If you are planting tomatoes in rows, make sure the rows are spaced 4-5 feet apart. If you are planting in containers, 5-gallons is the recommended minimum size pot, depending on the variety.

7. Irrigating Tomatoes

It is important to establish a regular watering schedule in order to reduce the likelihood of blossom end rot, sun-scorched leaves, and fruit cracking. Watering regularly and deeply is important, especially while your plant is flowering and fruiting. Just be careful not to overwater! Often throughout the summer, the leaves of your tomato plant may wilt. Many people take this as a sign that it needs water when this is actually just the tomato plants' efforts to conserve energy. Instead of relying on how your tomato plants look for knowing when to water, examine the soil. If the soil is dry to the touch, it needs to be watered. You always want to make sure the soil remains moist, but not soggy or muddy. In addition, make sure you are watering the soil site, not the actual plant itself. A layer of grass clippings or straw can also be added to help retain moisture. An alternative way to water is through a drip irrigation system that allows the individual to control the amount of water released as well as the timing, and it reduces water loss.

8. Staking and Trellising Tomatoes

staked tomato plants

Trellising or staking tomatoes is important to keep the lower parts of the plant off the ground. Leaves, stems, or vines that are allowed to rest on the ground will only encourage fungus, disease, and pests. Another reason you will want to trellis or stake plants is to help keep the stems and fruit from breaking. The weight of the developing fruit is often too much for the plant to support on its own. Use a combination of heavy-duty stakes, ties, hog wire, or tomato cages to hold the vines off the ground and help the plant support its fruit. And remember to implement your support structures when the tomato plants are young! If you wait too long, you will not be able to add your support structure without causing damage to the plant. Tomatoes require some guidance when being trellised, unlike other plants that are considered self-climbers, so keep an eye out for wandering branches and weave them gently into the trellis to help them find the support they need.

9. Fertilizing/Feeding Tomatoes

Tomatoes are heavy feeders and should be fertilized when planted, when fruiting, and then every two weeks until the first frost. Espoma Organic Tomato Tone fertilizer is what we recommend to feed your tomatoes. It is enriched with calcium to help prevent blossom end rot. No matter what you use, always use an organic fertilizer on anything you intend to eat. Non-organic systemic fertilizers will transmit chemicals through the fruit of the plant, and while the concentration of these chemicals may not be enough to kill you, it is definitely not healthy or recommended to ingest such chemicals. If your tomato plants are producing lots of leaves but very little fruit, this is most likely due to excess Nitrogen. In this case, a 10-10-10 balanced ratio fertilizer can be used to help encourage fruit growth. We also recommend a 2-3-1 fertilizer where the middle number (Phosphorus) is higher than the first number (Nitrogen). To enhance or improve flavor, you can add Epsom salts which contains magnesium and sulfur.

10. Tomato Garden Maintenance

Pruning suckering leaves is necessary to help the tomato plant conserve energy and nutrients and to improve fruit quality and quantity. Typically, you want to remove any leaves at the base of the plant that are within 6 inches from the soil. These leaves are serving no benefit, so pinching them off or pruning them helps divert the plants’ energy to other parts of the plant and will help them produce viable fruit.

11. How To Harvest Tomato Plants

As you harvest your tomatoes throughout the growing season, you want to be careful to not damage the tomato plant. Roughly tugging at the fruit will cause damage and can compromise your plant's ability to produce more fruit. Not being gentle can also bruise or damage your tomatoes, making them less desirable for consumption. So, when heading out to reap the harvests of your work, bring a pair of sharp scissors. This will allow you to simply snip the fruit from the plant, harvesting them without causing damage to either the plant or the fruit. Cutting the stems of the fruit versus picking them from the stems also allows the stem to stay attached to the fruit. This will help your tomatoes last longer after harvesting, giving you more time before the fruit goes bad; and if you've ever had a garden before, you know that eating all your fresh produce in time can be difficult!

Tomato Plant Troubleshooting Tips

When growing tomatoes, you are bound to run into at least one of these issues at some point or another. Sometimes, identifying the issues is the most difficult part of remedying an issue. Here is a quick overview of just a few of the most common problems you may experience while growing tomatoes. For more detailed information, please contact our Garden Center! We are happy to help identify whatever might be ailing your tomatoes and supply you with a remedy for the situation.

Blossom End Rot

Blossom End Rot

How to identify blossom end rot: Your tomatoes will appear healthy, but as they continue to grow and ripen, they will begin to turn black or grey at the base of the tomatoes where the original blossom once was.

What causes blossom end rot: This is happening to your tomatoes because they are not getting enough calcium. This is either because there is not enough available in the soil, or because the soil pH is too low for the roots to be able to absorb the calcium that is available.

How to fix blossom end rot: Before you plant your tomatoes at the beginning of the season, amend your soil so that it is at the proper pH. Adding things such as eggshells and other calcium-rich materials to your compost will also be helpful. Throughout the season, fertilize your tomatoes with a calcium fertilizer specific to tomatoes. This will help ensure that the nutrients are in the soil and that your plant is able to absorb them as needed.

Blossom Drop

How to identify blossom drop: This is very straightforward. Blossom drop occurs when blooms appear on your tomato plants and then fall off without producing any fruit.

What causes blossom drop: This can be caused by several factors, though most often it is caused by fluctuating temperatures. Tomatoes require nighttime temperatures of at least 55 degrees to retain their flowers, so if temperatures drop below that, your plants will lose their flowers. This can also be caused by lack of water, too much or too little nitrogen, insect damage, or lack of pollination.

How to fix blossom drop: While there is not much we can do to control the weather, you can always cover or insulate your tomato plants at night if temperatures are forecasted to drop below 55 degrees. You can also help avoid this by fertilizing regularly, treating your plants with neem oil as a preventative, and by attracting pollinators to your garden by planting other pollinator-friendly plants.

Blossom Drop

Poor Fruit Set

How to identify poor fruit set: This is when you have limited flowers and not many tomatoes. And often the tomatoes you do have will be small and tasteless.

What causes poor fruit set in tomatoes: This can be caused in part by the soil being too rich in nitrogen, which encourages leaf growth rather than flower/fruit growth. Your tomatoes could also be planted too close, which will not allow the wind to help pollinate the flowers, leading to a lack of fruit.

How to fix poor fruit set: It is best to have your soil tested so that you have a better idea of what might be going on beneath the surface. Be aware of spacing when planting your tomatoes at the beginning of the season to ensure that each plant has adequate space. If your plants are already in the ground, periodically shake the plants gently. This will help encourage some circulation and will help the pollen get from the stamens (male parts) to the pistils (female parts).

How To Grow Tomatoes

This topic can be quite extensive, and while we have done our best to cover all the basics, we are sure that there are still questions you may have about your tomato garden specifically. We are here to help you grow better, naturally, so if you need further assistance, never hesitate to reach out!


Farmers' Almanac Staff. "10 Common Tomato Plant Problems And How To Fix Them." Farmers' Almanac. Web. 21 April 2022. Date accessed: 5 May 2022. Retrieved from:


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