Denver’s growing season is short, about 150 days. It starts in early May and ends around October. The short growing season explains why spring brings excitement to vegetable gardeners. Despite the short growing season and climatic challenges, vegetable gardening in Denver is enjoyable. You only need to get your timing right to enjoy a bountiful harvest. It also helps to understand zone 6a gardening challenges and choosing the right plants for the region. This guide will help you familiarize yourself with spring garden planting in Denver to optimally utilize the short growing season.
Early Spring (April-May)
April marks the start of the planting season in Denver. While we still experience weather variability, gardeners are excited to welcome the growing season. Spring warmth awakens your garden! However, not all plants tolerate the weather variability in the April/May planting season. The early planting season only favors cool-season vegetables. Garden plants that can survive the April-May cold season include;
Vegetables:
- Lettuce
- Spinach
- Kale
- Broccoli
- Brussel sprouts
You can also sow beets, asparagus, carrots, Swiss chard, mustard greens, parsnips, and peas seeds in the open fields.
Flowers:
- Pansies
- Violas
- Zinnias
- Celosia
You can also include perennials in early spring planting to fully utilize the short growing season. Some perennials you can plant in April or early May include:
- Hostas
- Daylilies
- Columbine
April planting season is also an excellent time to plant shrubs like lilacs and forsythia. You can also consider other low-maintenance shrubs for your garden hedging and plant them at the beginning of the growing season.
Late Spring (May-June)
The last frost threat ends after Mother’s Day, paving the way for warm weather from mid-May. It also marks the start of the warm planting season. The late spring season allows you to plant warm-season plants or vegetables that may not survive frost stress. Crops you can sow in the late spring planting season include:
Vegetables:
- Summer squash
- Zucchini
- Beans
- Corn
Plant warm-season crops like tomatoes, peppers, and cucumbers in mid-May when frost threat is over. Mother’s Day is typically the last threat of snow or frost in Denver, but it’s important to keep an eye on your local weather forecast before planting outdoors. Other plants that do well in the late spring planting season include flowers and perennials like marigolds, petunias, zinnias, roses, and hydrangeas.
Tips for Success in Zone 6a
Zone 6a has a shorter growing season than zones 7 and 8. However, the short growing season can support a variety of crops, provided you follow recommended planting guidelines. The following tips will help you manage the growing season and maximize your harvest.
- Sunlight. Some plants thrive in the open fields, while others do well when protected from direct sunlight. Follow the recommended planting guidelines and plant each crop under the right conditions.
- Improve the Soil. Denver has alkaline soils that may not support many garden crops. You can improve the soil by adding organic matter or compost to grow numerous garden vegetables.
- Watering. Zone 6a is semi-arid, meaning crops require watering to thrive and increase yield. Check soil moisture content and water the crops depending on their moisture needs.
- Pest and Disease Control. Pest and disease-causing organisms increase in the spring planting season, posing a risk to your crops. We recommend preventative methods to control pests and diseases, but you can also use pesticides and herbicides to reduce infestation.
Visit Our Garden Center!
Spring is an exciting season for most gardeners. It is the season to prepare the fields and select crops to plant in the short growing season. With the correct preparation and crop selection, you will get a bumper harvest at the end of the season. Talk to us or visit our garden center for a wide selection of healthy plants.
