Although technically a fruit, tomatoes are the most popular “vegetable” grown in home gardens. But it wasn’t always that way. Up until the mid-1800s, the fruits of tomato plants were thought to be poisonous because they were grouped with the nightshade family of plants.

Now gardeners in our region spend most of the winter longing for the incredible taste of a home-grown tomato. Tomatoes are loaded with vitamins A and C and are rich in the powerful antioxidant Lycopene, making tomatoes one of the superheroes of the garden. No wonder so many gardeners spend so much time trying to grow them.grape tomato 001


Tomatoes aren’t more difficult to grow than other vegetables, but in our region they can be challenging. It’s important to keep in mind tomatoes are a tender, warm-season plant that requires a little more TLC than some other garden plants. Some of the important points to keep in mind when growing tomatoes in your garden include:

  • Selecting different types of tomatoes based on maturity dates. Choose short season, mid-season and long-season varieties to ensure a tomato harvest, no matter what the weather.
  • Waiting to plant until the soil and temperatures warm. Night-time temperatures should be a reliable 55 degrees before planting or use water-filled plant protectors for an earlier start.
  • Giving transplants time to get acclimated before planting. Harden off transplants slowly by giving them increasingly more sunshine over the course of a week.
  • Keeping up good gardening practices with consistent watering, fertilizing and weeding. Watch for insect pests or plant diseases and take action quickly.


  • Select a spot in your garden (or on your patio for containers) that receives about 8 hours of sunshine each day in the summer.
  • Tomatoes need a rich, well-amended soil. Dig in compost, well-aged manure or other soil amendment to make a well-drained planting site. Set up a drip irrigation system or soaker hose to ensure deep watering on a regular basis.
  • If planting your tomatoes from seed, start seeds indoors about 6 weeks before the average date of the last spring frost.
  • If planting tomato transplants, select healthy plants (6-8 inches tall) with stocky stems and dark green leaves. Pinch off any flowers or fruit before planting to give the plant a good start.


  • Tomatoes are warm-season plants so wait to plant until the danger of frost has passed. The garden soil should be at least 60 degrees, and night-time temperatures should be a reliable 50-55 degrees. Chilly night-time temperatures may cause blossoms to drop. Deformed tomatoes (called catfacing) are also a result of cool weather at blossom time.
  • Note: If you garden at higher altitudes, you’ll need to plan ways to create a warm microclimate to ensure adequate tomato-growing time. Wall O’ Water, or other plant protectors, make a difference in planting time. Use them to warm the soil for a week before planting to be able to plant while the weather is still cool.
  • When the weather has warmed, plant in the late afternoon or on a cloudy day, if possible. Dig a small planting hole, remove some of the lower leaves from the tomato plant and plant in the soil up to the remaining leaves. For tall, leggy plants, plant lengthwise and bury some of the lower stem. Plants will grow roots all along the stem.
  • Place tomato plants a minimum of 2 feet apart in rows that are at least 36 inches apart. Build up the soil to create a small water basin around each plant to help direct water to the roots.
  • Tomatoes need a tomato cage or trellis to support plants and to keep the vines off the ground. Add tomato cages when planting. Mulch around the plant with thin layers of straw, dry, untreated grass clippings or shredded leaves to conserve water, control weeds and regulate soil temperature. The clippings shouldn’t touch the plant stem.


  • Keep an eye on soil moisture and don’t let plants dry out. Water at the roots of the plant and water deeply to 8-10 inches. Avoid splashing water on the leaves.
  • Tomatoes need nitrogen for vegetative growth and color, so fertilize tomatoes with a well-balanced fertilizer when plants start to grow and again after they have set several tomatoes. It’s a good idea to keep nitrogen levels up in mid-to-late summer to prevent Early Blight and to improve the tomato yield. Stop fertilizing in mid-August so vine growth will slow and fruits will ripen.

During the summer be sure to watch for these common tomato problems:

  • Blossom-end rot appears as a dark, soggy spot near the blossom end of the tomato. Prevent blossom-end rot with proper irrigation to make sure the soil is evenly moist, especially during dry weather. Mulch helps regulate soil temperature. Another method of prevention is to make sure plants receive adequate fertilizer applications.
  • Sunscald is like a tomato sunburn that causes papery patches on tomatoes. Prevent by protecting tomatoes from exposure to intense sunlight. Keep leaves healthy or use shade cloth to protect the fruit as it ripens.
  • Growth cracks appear as either circles at the stem end of the tomato or as cracks down the sides of the tomato starting at the stem. Rapid growth because of wet weather followed by dry weather causes this kind of cracking. Regulate soil moisture with consistent deep watering to help lessen the effects.
  • Early Blight is a tomato disease that shows up as yellowing of the lower leaves of the tomato plant start before moving to the next layer of leaves. To prevent Early Blight, give tomatoes plenty of planting space to allow air to circulate. Create a strong trellising system to keep tomatoes off the ground and avoid splashing water on tomato plant leaves when watering.
  • Fusarium and Verticillium are diseases that start in the soil and cause problems to a tomato plant’s stem which leads to plant decline. When purchasing tomato plants or seeds, buy those that are labeled “VFN resistant.” Another preventive method is to avoid planting tomatoes in the same location every year.
  • Here are the most common insect pests to watch for on your tomato plants:
  • Aphids are tiny insects that leave a sticky residue on the underside of leaves. Control aphids with insecticidal soap, horticultural oil or Neem oil. Attract lady beetles (lady bugs) into your garden by planting flowers like dill, coriander and alyssum.
  • Blister Beetles are striped gray or black beetles about ½-inch long that also eat tomato foliage. Use a pyrethrin-based insect control.
  • Tomato hornworms are 3-inch long green caterpillars with stripes on their sides and a horn-like appendage on one end. Hornworms can strip a plant of its leaves in just one day. Pick them off plants by hand and dispose of them in a bucket of soapy water or use Bt (Bacillius thuringiensis) dust on plants.


Tomatoes typically ripen about 8 weeks after the flowers first appear. Clip or pick tomatoes from their vines when red and ripe. The only time to pick tomatoes before they’re ripe is near the end of the season when the first hard freeze is predicted.


Plant Tomatoes with these companions:

  • Basil
  • Carrots
  • Celery
  • Cucumbers
  • Onions
  • Marigolds
  • Mints
  • ParsleySage
  • Sunflowers and other flowers that attract pollinators

Avoid planting with:

  • Cabbage
  • Corn
  • Fennel


  • Soil thermometer
  • Soaker hose or drip irrigation
  • Wall o’ Water or other plant protectors
  • High-quality compost or well-aged manure
  • Well-balanced fertilizer
  • Organic mulch
  • Tomato cages

Nick's Garden Center & Farm Market * 2001 South Chambers Road * Aurora, CO 80014 * (303) 696-6657