KSL Greenhouse: Everything to know about tomatoes

SALT LAKE CITY — Tomatoes are native to Mexico, Central, and South America and Indigenous tribes domesticated them. When the Spanish arrived in Mexico in the 1500s, they found several varieties of tomatoes being sold in local Aztec markets.

At the same time, tomatoes embarked on a remarkable global journey. They were introduced to various areas within the Spanish Empire and spread to many areas of the world.

However, when tomatoes were brought to Europe, they were met with suspicion because they belonged to the nightshade family, which has many poisonous members. This fear was eventually overcome, though, and tomatoes were incorporated into the various cuisines of Europe.

Some of our favorite foods, such as pizza and spaghetti, would not exist without their introduction into Europe.

Related: How to protect your tomatoes from heat damage

Today, tomatoes are adored as the most-grown garden vegetable in Utah. We eat them fresh, cook with them, and preserve them for later use. However, as we grow them in our gardens, they sometimes do not perform well.

For example, recent sustained high winds along the Wasatch Front stunted and distorted their new growth this year in many areas. But newer growth seems to be emerging normally.

USU Extension has observed herbicide damage on tomatoes and other plants. This happens when someone applies a lawn weed killer or another herbicide containing 2,4-D or Dicamba. In hot weather, these products can volatilize and drift, sometimes over a mile if the wind blows when the herbicide is applied.

This type of damage is indicated by new growth emerging that is distorted, curled, and sometimes elongated and leathery. With heavier exposures, leaves on the entire plant may do this.

Every 3 to 4 years, we seem to have an outbreak of curly top, a viral disease that the beet leafhopper spreads. We have seen some, but it seems to be an off-year. This disease is harder to avoid, but others are less so.

Keeping tomatoes disease-free

To keep tomatoes as disease-free as possible, do not plant them in the same spot more than once in three years. Additionally, do not plant tomatoes where you had peppers, tomatoes, or eggplant the previous year. These are closely related and susceptible to the same diseases.

The time tomatoes ripen depends on the ripening time stated on the garden center label and outdoor temperatures. Temperatures above 90 degrees during the day and 70 degrees at night can cause flower abortion and slow fruit development and plant growth. This is why we get most of our fruit in late summer and early fall when temperatures are cooler.

Many local gardeners have started shading their plants using low tunnel structures or sturdy, wind-resistant stakes, using shade cloth with 20% to 30% shade. Plants can be shaded from the top or side. This often causes fruits to ripen a few weeks earlier and prevents sunscald.

Other fruiting vegetables can also be shaded. Shade cloth is available online and from local farm and garden retailers. So, if you are becoming impatient about when your tomatoes will ripen, be patient! They will come.

Taun Beddes is a host for the KSL Greenhouse show. You can hear more from Beddes by listening to the The KSL Greenhouse, live every Saturday from 8 a.m.-11 a.m. or by checking out the shows podcast episodes. You can follow the show on Facebook, Instagram, YouTube, and on our website.

Related: What is curly top disease and how do you identify it?