Varietal Selection
New varieties of vegetables are constantly being developed. Each vegetable crop (tomatoes, sweet corn, pumpkins, etc.) may have hundreds of named varieties, thus it is impossible to list and describe all of them. Therefore, it is important to regularly talk to knowledgeable individuals to learn about new varieties. The recommendations given in this production guide for each specific crop are based on limited testing. They have been selected to provide some reference and most are suitable for the primary production areas of the Intermountain West region. A particular variety may perform better than the prevailing standard variety under certain conditions.
Keep the following in mind if you are considering changing to a new variety:
- Use seed catalogs or other sources to identify a variety that has similar production characteristics. These characteristics may include maturity times, growth habits, fruit size, cold/ heat tolerance, or pest resistance. Visit SeedQuest for a listing of the major seed producers.
- Grow the new variety on a small scale for 1 or 2 years. Compare the new variety to your farm's standard variety so you can see if the performance is the same or better under your conditions and management practices.
- Evaluate the new variety's performance in the marketplace, noting customer comments.
- Use this information to adopt or reject the new variety.
Ideally, your selected varieties should have good resistance or tolerance to many of the pathogens found on your farm. Keep in mind that varietal resistance to disease may break down due to different pathogen strains, when environmental conditions favor the organism, or when there is reduced natural plant resistance. If crop-threatening diseases occur on your farm, genetic resistance is an effective and low-cost strategy to minimize disease outbreaks.
Vegetable variety types may be labeled as heirloom, open-pollinated, hybrid, genetically modified, or organic. Heirlooms are “old” varieties selected and preserved from historic seed lines over many generations. There is some debate over how old a variety needs to be before it can be considered an heirloom. They are generally open-pollinated, but not all open-pollinated varieties are heirlooms.
Open-pollinated varieties are cross- or self-pollinated crops where plants are allowed to intercross freely with other plants in the field. Open-pollinated plants are more genetically diverse, but as long as no new pollen is introduced to the population, the resulting seeds (and plants) are relatively true to type (similar to the parent plants). Hybrid varieties come from crossing specific individuals where pollination is carefully controlled. Hybridization aims to isolate unique traits from plants through classical breeding techniques. Once these traits are isolated, specific crosses are made so offspring express the traits. The specific parents are maintained to continually breed this hybrid. Hybrid seeds tend to be unstable and if you save seeds from them, the resulting plants are often different (not true to type) from the hybrid plants and may be less vigorous and productive.
Developing genetically modified (GM) varieties entails inserting genetic material from different plants, animals, or organisms into the desired crop. These new GM varieties have new traits which do not occur naturally in the crop. These traits may include improved disease or insect tolerance, resistance to specific chemicals like herbicides, or tolerance to adverse environments.
Organic varieties can be heirlooms, open-pollinated, or hybrids, but they cannot be GM crops because to be organic, seeds must be harvested from plants that were grown following organic production practices.
General Recommendations for Growing Transplants from Seed
| Crop | Seeds / ft2 | Seeding Depth (inches) |
Optimum Germination (F) |
Germination Time (days) |
Optimal Growth Temperature |
Grow Time** (weeks) |
|
|---|---|---|---|---|---|---|---|
| Day (F) |
Night (F) |
||||||
| Asparagus | 36 | 1/4 - 1/2 | 75 | 8-10 | 65-70 | 60 | 8-12 |
| Broccoli | 48 | 1/4 | 85 | 4 | 65-70 | 60 | 5-7 |
| Cabbage | 48 | 1/4 | 85 | 4 | 65-70 | 60 | 5-7 |
| Other Brassicas | 48 | 1/4 | 80-85 | 4-6 | 65-70 | 60 | 6-8 |
| Cantaloupe | 36 | 1/2 | 90 | 3 | 75-80 | 65 | 3-4 |
| Cucumber | 36 | 1/2 | 90 | 3 | 70-75 | 65 | 3-4 |
| Eggplant | 36 | 1/4 | 85 | 5-6 | 75-85 | 65 | 6-8 |
| Endive | 60 | 1/4 | 70-75 | 3 | 65-70 | 60 | 4-6 |
| Lettuce | 60-80 | 1/4 | 70-75 | 3 | 60-65 | 45 | 4-6 |
| Onions | 80-100 | 1/4 | 75 | 4-6 | 65-70 | 60 | 8-12 |
| Other Leafy Greens | 60-80 | 1/4 | 70-75 | 3-5 | 60-70 | 45-60 | 4-6 |
| Peppers | 36 | 1/4 | 85 | 8 | 75-80 | 65 | 7-9 |
| Summer Squash | 36 | 1/2 | 90 | 3 | 70-75 | 65 | 3-4 |
| Sweet Potato | --- | 1/4 | --- | --- | 75-85 | 65 | 5-6 |
| Tomato | 36 | 1/4 | 85 | 5-6 | 65-75 | 60 | 6-8 |
| Watermelon | 36 | 1/2 | 90 | 3 | 75-80 | 65 | 3-4 |
Note: Temperature, light levels, nutrients and other factors can influence grow times.
Average number of weeks required to grow to transplantable size.