High Elevation Gardening for the Southwest
High elevation gardening is for those of us 5,000 ft and above in the southwestern US. Late frosts and late snows in the spring and early freezes and early snows in the fall are characteristics of the mountains of the southwest. If you are aware and plan, these characteristics won’t cut your harvest short.
You will need information specific to your zip code, because in the mountains, 10 miles can make a big difference.
You can use 50% or 90% frost dates, but just remember that 50% is 50-50 that a frost will or won’t happen. Use this information to determine when to plant. For example, if a seed variety says to plant 2 weeks after the last frost, then plant 2 weeks after your last frost date.
With your seeds or seedlings, keep an eye on days to maturity. Compare days to maturity to frost-free days. I have 100 frost free days. Not a lot.
First strategy, larger plants
Strategy one for high elevation gardening is to start with larger, more mature plants. Buy gallon plants or at least quarts. This is going to give you about a 3 week jump on growth. The six- pack size plants, tomatoes for example, often will not have enough time to mature if planted when it is warm enough. In my case, warm enough is June. Don’t worry though, with a raised bed, planting fewer, larger plants is an excellent strategy because your plants will be very prolific.
wall of water
Second strategy, extend the season
Strategy two is to extend the growing season. This can be done with a cold frame , wall of water, or covering with plastic. If you use plastic, be sure to prop it up over the plants so as not to crush or burn them. Gallon or half gallon containers of water placed near the plants can help prop the plastic and also store heat.
Wall of Water
Wall of water can be very effective in high elevation gardening. Cells of water surround the young plants providing extra heat and protection. At the very beginning of the season, don’t fill the cells all the way. This causes the top to form a tepee and really protects the young plants. Last year, we had a snow over Memorial Day, and wall of water saved my tomato plants.
A word of caution, plants that don’t reach above the walls before the summer rains can mildew. This happened to my peppers. So it’s best to remove them, once it’s warm enough. I also used them on zucchini and they did great, but needed to be removed before the plant got too big. I don’t find the wall of water of too much use in the fall, because whatever fruits you are trying to save are well away from the wall.
A cold frame is a mini greenhouse placed over young plants. In some locations, a cold frame can allow gardening over the entire winter! If you make your own cold frame, make sure the top opens so it can be propped if necessary.