This article was written by Mary Roduner, former SDSU Extension Consumer Horticulture Field Specialist.
Spring is coming and will be here before we know it. Gardeners are reading through catalogs, looking at that new variety of green bean, or maybe a gorgeous new tomato. The catalogs are written to hook you in by making these varieties look as good as possible. The photos are generally mouthwatering and the descriptions often seem a bit over-the-top.
Know Your Growing Season
The important question for most gardeners is whether or not a particular variety will grow in their area. South Dakota’s growing seasons vary greatly from North to South and East to West with extremes in moisture, soil composition, and temperature. Annual vegetables are rated by the number of days from planting or transplanting until the edible portion of the plant is mature. This can be the leaves of kale or the fruit of tomatoes and peppers.
Our growing season is primarily determined by the number of frost-free days for a particular location. There are as few as 70 frost-free days in Custer. On the other end of the spectrum is Yankton with 157 frost-free days. It is also important to note that some vegetables need warm temperatures to develop and mature properly. While Custer may typically have a 70-day growing season, it stays rather cool in Custer all summer, so warm season vegetables, like tomatoes, peppers, and cucurbits, will be challenging to grow to maturity without a great deal of site manipulation to protect the plants and warm the soil.
Other vegetables are called cool-season or early-spring vegetables. This includes crops such as broccoli, kale, cabbage, and leafy vegetables like lettuce. These should have days to maturity listed, but many will also be categorized by how much heat the plants can tolerate before the edible portion of the plant becomes too bitter to eat. When the temperatures heat up, kale and cabbage can become too bitter to eat, while broccoli and lettuce plants will bolt (produce flowers) and become very bitter as they come to the normal end of their life. So, if you have a short growing season with cool temperatures all season, you can easily grow the cool-season crops. But if you typically have a short, cool spring followed by a rapid climb in temperatures for summer you will need to either plant these early in the season or try a late summer planting for a fall harvest.
Choose the Right Varieties
When choosing which varieties to grow, start with the name brand catalogs. Look for catalogs that list hardiness zones, scientific names, and days to maturity. Some online catalogs are now allowing customers to give varieties numerical ratings and comments on them. This is an excellent way to find out the experiences of other gardeners and if the taste really is as good as claimed. Look for the reviews of people in the same type of growing area as yours to make a better decision.
A look at several types of vegetables and fruits will explain what to look for. The thought process involved in choosing a particular variety will be demonstrated. All the varieties listed below are being used as examples only and are not endorsed by the writer.
An early spring or late fall vegetable. Broccoli cannot take heat. Once the temperatures are over 80°F plants begin to produce bitter sulfur compounds. Plants grow best by starting the seed indoors and transplanting young plants. They also produce best in cool weather.
- Broccoli, De Cicco: 50 days to maturity after transplanting. Produces side-shoots.
- Broccoli, Waltham 29: 74 days to maturity after transplanting. Produces some side shoots.
- In an area where summer heat moves in quickly, the De Cicco is more desirable. It produces the main crop quickly and side shoots can be picked until it gets bitter. This may be a good variety for Yankton. Waltham 29 can be grown in areas with a longer cool season during either the spring or fall. Plant it very early and cover it when there is a danger of frost.
This is one of the most heat-sensitive vegetables we grow. Many varieties will bolt, producing a flower stalk, at 80°F. Once lettuce starts bolting, it is too bitter to eat.
- Marvel of the Four Seasons: 54 days from seed. This is a lovely lettuce that is one of the first to bolt. It is only good for long cool seasons.
- Bronze Arrowhead: 40 days from seed. This lettuce holds in the garden for a long time and rarely bolts or gets bitter.
If you want to pick lettuce as long as possible, look for the varieties that state “slow to bolt” in the description. The term "slow to bolt” will vary depending on how a particular seed company defines the term. You may need to try several varieties and choose the one that bolts latest in your area.
All tomatoes must be started indoors in South Dakota and North Dakota. We do not have a long enough growing season to reliably start seed in the ground. Tomato plants need a soil temperature of 50°F to grow and thrive; any cooler will damage the plants. If you live in an area with a very short warm season, look specifically for varieties with the shortest days to maturity. While heirloom varieties taste best, hybrids will provide the most vigor to produce a crop before frost.
- Early Girl, hybrid: 52 days to maturity from transplant. One of the earliest varieties available and is generally available from most nurseries. While not the best-tasting or largest tomato, when the season is short this may be one of the best. options.
- Brandywine: 85 days to maturity from transplant. This is an heirloom variety that many gardeners try to grow. It needs a long warm season because it doesn’t produce fruit until later in the season, and it is prone to diseases.
When you choose tomato varieties, be sure to read between the lines for plant descriptions that sound too good to be true. Choose growth options best for your area and needs, such as determinate or indeterminate growth. Plants with determinate growth will set flowers at the ends of branches, producing the majority of their fruit as one large crop with a few straggler fruits later on. This type of growth is best for short season areas or people looking to can large amounts of tomatoes over a short period of time. Indeterminate tomatoes produce flowers on side shoots, growing and producing a steady crop of tomatoes until frost.
Check several sources to be sure the plant descriptions match and make use of online catalogs with comment sections. The length of your growing season is the most important variable when deciding which tomatoes to grow.
Choosing varieties for your garden does not have to be hard. Learn about your unique climate conditions, do a little research about different varieties, and don’t be afraid to try new things.