Growing Tomatoes 101

Site Selection

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. 6 hours of sunlight is generally the minimum requirement for successful tomato growing. Depending on personal circumstances and varieties, tomatoes can be grown in containers, raised garden beds or rows.

Amending the Soil

Tomatoes prefer a soil pH of about 6-6.8. (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 a more acidic and favorable pH level. Work 3-4” of the chosen soil amendment into 4-6” of existing soil to improve soil properties.

Variety Selection

Depending on whether you are growing in containers, raised beds or in rows, you will want to select a variety or varieties that are suitable for the amount of space you have.

Heirloom vs. Hybrid

Heirlooms indicate that the seeds are openly pollinated and that the seeds collected produce plants that resemble the parent plant. Hybrids indicate that the seeds were crossbred from 2 or more parents.

Determinate vs. Indeterminate

If tomatoes are labeled “Determinate” that means that they grow to a certain size and typically produce fruit all at once. Indeterminate tomatoes continuously produce fruit while temperatures remain warm.


A safe bet to planting is to wait until May 30th, which is the first frost free date in the Front Range area this year. Typically, you want to cover the stem up to the plants’ leaves because the roots will grow along the buried stem to increase the plants’ strength and vigor.


Bush varieties will take up a lot more room and will need adequate spacing (for instance 36”) than other varieties. Spacing tomato plants any closer than 24” will reduce air flow/circulation and will increase risk for pathogens. If you are planting tomatoes in rows make sure they are spaced 4-5 feet apart. A 5 gallon container is the recommended minimum size pot for container gardening.


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 mindful that you are not over watering! Touch the soil to make sure it remains damp, 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.

Staking and Trellising

Trellising or staking tomatoes is important to keep the lower leaves or vines off the ground since they can act as vectors to pathogens. You will also want to trellis or stake plants to keep the stems and fruit from breaking off. Use a combination of wire, ties, hog wire or tomato cages to hold the vines off the ground. Tomatoes require some guidance when being trellised, unlike other plants that are considered self-climbers.


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. A 10-10-10 balanced ratio fertilizer can be used when tomatoes are producing lots of leaves but very little fruit. This is most likely due to excess Nitrogen. We also recommend a 2-3-1 where the middle number Phosphorus is higher than the first number Nitrogen. To enhance or improve flavor you could add Epsom salt which includes magnesium and sulfur.


Pruning suckering leaves is necessary to help the tomato plant conserve energy and nutrients to improve fruit quality and quantity. Typically you want to prune the leaves up from the first 6” of the soil. Pinching off or pruning suckers conserves the plants’ energy to help it produce viable fruit.