Selecting tomatoes adapted for a short season

Growing tomatoes in short-season areas like Eastern Idaho can be challenging.

Late spring frosts and a limited growing season make it essential to choose the right tomato varieties. By starting plants indoors and selecting early maturing varieties, gardeners can increase their chances of a bountiful harvest.

Understanding the different growth habits of tomato plants – Determinate, Indeterminate, and Semi-Determinate – can also help in choosing the best variety for your garden space and needs.

For more information on starting your vegetable plants indoors, reach out to your local extension office.

Selecting tomato varieties suited for short-season growing is essential. Look for varieties locally or online that ripen in about 50 to 72 days, as these will produce fruit earlier in the season. Although it is important to note that not all tomato plants have the same growth habits and thus will not produce the same quantity of fruit.

Tomato plants have three main types of growth habits: Bush-type (Determinate), Vining- type (Indeterminate), and Bush/Vine-type (Semi-determinate).

Determinate tomatoes are compact and may not require support, although staking or caging is recommended. These varieties vary in size from 18 to 60 inches in height. These bushy varieties will produce a flush of fruits within several weeks when they reach their mature height. They will then stop growing and be finished for the season. Indeterminate tomatoes require support, such as cages, stakes, or trellises. They continue to grow like a vine and produce flowers and fruit along the stem until the cold weather or adverse conditions kills them. These varieties yield fruit over a longer period but set fruits later in the season and can get up to twice (120 inches) as large as determinate varieties. Semi-determinate tomatoes will grow larger than determinate but smaller than indeterminate varieties and will also require support like Vining-type tomatoes. This growth habit is common in-home garden stores, offering a balance between Determinate and Indeterminate tomato varieties. Semi-determinate varieties like determinate will produce the large flush of fruit and then will be finished for the season.

The growth rate, fruit production, and ripening time of all tomato types are influenced by environmental factors such as temperature, moisture, and sunlight. Providing optimal growing conditions will help ensure healthy plants and a productive harvest.

Tomatoes will produce good fruit when they receive at least seven hours of sunlight a day. They also need to stay warm at temperatures greater than 60°F, in colder areas locate the plants next to large heat absorbing objects like masonry, boulders, buildings if there are no cold pockets. Most tomato varieties will have issues with pollination if temperatures are below 60°F. If temperatures stay consistently below 60°F row covers, high tunnels, or greenhouses may be required. Even deep watering throughout the season will help reduce disease issues.

Your choice of tomato variety can be determined by the space availability, quantity, and duration of fresh tomatoes you need. Determinate tomatoes are well-suited for containers and compact spaces, while Indeterminate varieties thrive when transplanted into the garden. Understanding the growth habits of tomato varieties will help you select what works best for your situation.

There are several varieties with similar names and while this table below provides some there are many others to choose. This table is a selection of tomato varieties adapted for Idaho’s short growing season, from a publication by the University of Idaho Extension:

Selecting the right tomato variety is key to a successful harvest in Idaho’s short growing season. Determinate varieties are ideal for container gardens and compact spaces, while Indeterminate varieties provide an extended harvest when properly supported.

Semi-Determinate types offer a balance between the two. By planning ahead, protecting plants from cool temperatures, and choosing early-ripening varieties, gardeners can enjoy fresh, homegrown tomatoes even in a somewhat challenging climate.