|Climate determines what plants a gardener can expect to grow and survive. Our cool, semi-arid climate is perfect for rock gardening or xeriscaping but gardeners need to understand the limitations of vegetable, flower, and fruit cultivation. Our growing season is about 85 days and our USDA zone is 4b. The following describes the climate for our Rocky Mountain high altitude
Temperature. Our winter temperature lows usually average -20°F. However, some years our winter temperature drops to -50°F. Early spring temperatures can rise to 80°F causing fruit trees to bud out but night temperatures drop well below freezing causing the buds to freeze. However, these warm spring temperatures allows early season crop extenders such as Remay and Wall-O-Waters to work well as the soil warms sufficiently to keep the plants above freezing over night.
Summer temperatures range between 40°F to 45°F at night and 90°F to 95°F during the day. The cool night temperatures are ideal for greens and lettuce but tomatoes will not set fruit below 50°F. The warm daytime temperatures are ideal for corn and other warm season crops. A high altitude gardener can overcome these temperature variations using aids such as IRT mulch for tomatoes and corn and providing shade to cool loving plants.
During the gardening season, we may have thunderstorms almost every afternoon. However, the sun is very intense and dries the soil quickly. Some years, we may not have rain for a whole month. I use mulches such as straw and IRT plastic to hold moisture in the soil. I bury "leaky" hose in all the vegetable garden beds so I can water as required during dryer periods.
Autumn is a very dry time here. Any trees or perennials planted in the summer are not dormant yet and need supplemental watering at this time to survive.
We usually do not have much wind during the summer months. However, when the wind does blow, plants desiccate quickly due to the very low humidity we enjoy. My vegetable garden is located in a low meadow, well protected from wind.