I thought this next post should be something about the gardening conditions at 8600 ft. On average, we get, maybe, 75-90 frost free days a year. Along the Front Range of Colorado (I-25 corridor from Fort Collins to Colorado Springs), the average frost-free date is May 15th, after which you can feel fairly safe about planting vegetables and tender annuals. Up here, the average frost-free date is June 2nd and even then I wouldn’t count on it. I have planted outside on June 2nd and the next day we got snow. I should qualify that statement by telling you that I am very fortunate to have a small greenhouse where I can grow vegetables that require more than 90 frost-free days or that cannot tolerate the cool night temps of summer (usually in the 40’sF). I purchased a used, 6′ x 8′ aluminum frame greenhouse from a friend of mine and it has served me well. I put a portable electric heater that has a thermostat in the greenhouse, and run heavy duty electric cord to the house for electricity to power it. This helps early in the season when the temps are still going below 32F. During the summer, it is unplugged as the daytime heating in the greenhouse compensates for the chilly nights. The average daytime temps during the summer are between 75-80F. If it gets above 80F, it’s a real heat wave. The temperatures at this elevation are generally about 20 degrees cooler than along the Front Range, so planning your garden accordingly is a must.
The soil, is as expected, rocky. After all, these are the Rocky Mountains. The gardens that we use most frequently have all been cleared of big rocks which are then used as accent stones or borders. The soil is mostly sandy loam which is a welcome change from the heavy clay soils of the Front Range. The gardens that have are using have also been amended with aged horse manure to help with drainage, texture and fertility. Thankfully, due to the elevation, diseases and insect pests are at a minimum. Aphids and whiteflies have, on occasion, found their way into the greenhouse but the plants outside have been disease and insect free. The main concern in high elevation gardening is herbivory. The deer love the roses, the chipmunks love the pansies and most other flowering plants and the rabbits will eat most anything. And, there are also the moose that love to trample anything they happen to walk through.
This offers a pretty good idea of the conditions of gardening at high elevation, so future posts will be more about the plants.
Mountain Gardening: Not for the faint of heart 