How to Garden at High Altitude: Complete Guide


Whether it is for aesthetic purposes or to have a self-sustaining food source, Gardening is an enriching experience. But it comes with its own challenges, which only increase if you are in a high elevation zone. However, it is possible to garden at a high altitude as long as you know what to do and are willing to put in the effort.

To garden at high altitudes, you must pay close attention to climate, growing seasons, pest control, moisture control, soil conditions, plant and vegetable selection, and timing. Today, the goal is to take a step-by-step look at the different skills, tools, and knowledge you will need to start your high altitude garden.

Know Your Hardiness Zone

According to the USDA, a plant hardiness zone is a standard by which farmers or gardeners can determine the likelihood of a specific plant or crop being able to thrive in certain areas.

The map divides North America into 11 different zones that are differentiated by a ten-degree difference in winter compared to neighboring zones.

For example, Zone 9, which contains warmer states like South Carolina and Georgia, has an average winter temperature of 20 to 25 degrees Fahrenheit. As for states like Vermont and New Hampshire, located in Zone 5, they have an average winter temperature of -20 to -25 degrees Fahrenheit.

States like Colorado and Wyoming have an average elevation significantly higher than the rest of the United States. When farming or gardening in states like these, it is important to identify what hardiness zone you are in. Doing so will make it easier for you to identify plants that will survive the winter.

When you purchase your plants, they will most likely have a “Hardiness Zone” indicator on the information tab. You will want to make sure that the information matches the zone you intend to plant your new seedlings.

Here’s a quick video explaining the zones:

Select Plants Suitable for High Altitude Gardens

When gardening at high altitude, the first step is determining which plants will survive and thrive at higher altitudes. Most likely, using plants that survive well in cold temperatures will be necessary. After all, for every 1000 feet of elevation above sea level, the temperature can drop by as much as 5.4 degrees.

Temperature is not the only problem you will have to deal with at high altitudes. A few other problems include:

  • Lower humidity
  • More direct sunlight
  • Increased drastic weather changes

The growing season will also be shorter in the mountains, so you will want to find seeds with the shortest “days-to-maturity” number. The less time you spend germinating and growing your seedlings during the limited growing season, the more likely you will have a high yield in your crop.

Some good starting selections are leafy greens and root vegetables, such as kale, spinach, arugula, carrots, radishes, turnips, and parsnips.

Kale specifically is an extremely hardy plant that thrives in the cold mountains of Scotland. If it survives there, it can survive in the United States and provide you with lots of nutritious food.

We have a full article on the Top 20 High Altitude Plants For Gardening, but here’s a quick version.

Suitable Plants

One of the most important factors when considering which plants to use is how they survive in cold temperatures, so plants resistant to frost or entirely frost resistant are ideal choices. A few of the more resilient plants you can grow are:

  • Brussels
  • Kohlrabi
  • Broccoli
  • Leeks
  • Cabbage

Those are not the only plants that have a high resistance to frost and cold weather. In fact, it is a rather expansive list that includes the previously mentioned kale and a plethora of other edible staples like English peas, turnips, and spinach. However, not all plants are as resistant.

Many plants are only slightly tolerant to frost, finding it difficult to survive in cold weather and high elevation. If you plan to grow vegetables such as these, which include things like carrots and potatoes, you will need to consider options to keep them warm or turn to the frost-resistant options.

Trees, Shrubs, and Woody Plants

Trees, shrubs, and woody plants are more challenging to protect in harsher climates, meaning you will have to choose your trees and shrubs carefully to ensure that their needs are met at a higher elevation.

After all, trees are generally more expensive than smaller plants, making their survival all the more important.

An important factor to consider regarding trees is whether they bear fruit. If they do, the variety of fruit will have its own hardiness. For example, a Lodi apple tree does just fine at higher elevations, whereas a Honeycrisp apple tree will not have a high chance of survival. Make sure to review the days-to-maturity number and hardiness of fruit trees.

If you are looking for shade trees for aesthetic purposes, picking a very hardy species will likely work out in your favor. When it comes to woody plants and shrubs, hardiness varies widely depending on the species.

Here’s a lengthy video but interesting info about high altitude plants:

Buy the Right Equipment

The first thing you might want to consider is keeping a gardening journal. While much less direct than the other equipment you may need, keeping notes and understanding the differences in gardening at higher elevations will allow you to learn and make adjustments to suit your unique needs. Other useful tools include:

  • Plastic Covers: Putting plastic covers over your rows or garden beds will help protect against unforeseen frosts. They can also be beneficial in protecting against birds and some pests. Best of all, they are easy to set up, especially if you have raised garden beds.
  • Raised Garden Beds: Utilizing raised garden beds will allow you to avoid the potentially rocky ground you will encounter in mountainous regions. They will also warm up more quickly than ground soil, which can add a week or two to your growing time, and little is more important in high altitude gardening than time.
  • A tool to Measure Soil Fertility: Tools that measure soil fertility are available at most hardware stores, but you will need one that can measure nitrogen, potassium, phosphorus, and other trace elements. The soil is considered less mature at higher elevations and has less of the nutrients vital for plant growth.

Check out the Gardening Equipment we recommend after years of trial and testing.

Know the Importance of Soil Quality

As elevation increases and temperature drops, the decomposition rate slows down, which has a significant effect on soil fertility. You may encounter soil that looks healthy but has extremely high pH levels.

You may also encounter soil that has a lot of iron but still allows your plants to become iron deficient because of high carbonate levels.

This makes assessing your soil vital. Only once you have assessed it can you add organic material to increase or decrease nutrients.

If you are keeping track in a journal, you will be able to understand the changes in soil fertility over time. Changing soil fertility is a long process, one you do not want to have to repeat due to a mistake.

Soil with high alkalines needs precise applications of sulfur and lots of organic material. If you are on an eastern slope, which means you may have a high clay content, you will want to add more organic material or gypsum.

However, if the clay soil is also high in alkaline, you will want to avoid adding gypsum since that will make pH levels too high.

Soil cultivation is just as important as plant cultivation. The goal is to create a patch of soil that will become self-sustaining.

Most mountainous soil will require some modification, but your hard work will pay off once you establish and understand the rhythm of your plants and soil through the season.

Here’s a quick info video about soil:

Location, Location, Location

Location matters in everything, particularly when it comes to gardening. It only becomes more important when high altitudes are thrown into the mix, with otherwise harmless obstacles become potential pitfalls to successful plant growth. Here are a few location related issues to keep in mind as you proceed:

  • The slope of your location plays a big role in determining your garden’s success. Due to high elevation, cloud cover becomes more important, a problem to avoid as it will stunt your plants.
  • Also, the same mountain can have a cloudy slope and another one where rain comes in constantly, so finding the perfect slope is vital.
  • Sunlight is another issue for gardening. You want to find a site that gets at least six hours of sunlight a day, which means avoiding tall trees or outcroppings of rock that will block the sun.
  • Usually, southerly facing slopes are safer locations to start growing, tending to have warmer soil and a later start to the frost season.

Be sure to avoid northerly and easterly slopes, especially northerly slopes, as there is minimal sunlight. You will also want to avoid planting in depressions since they experience frosts more frequently than slopes.

Learning the geography at higher altitudes will prove helpful throughout your gardening adventure.

Pests of Higher Altitudes

In addition to a unique set of environmental circumstances, you will face a uniquely ravenous category of pests.

Due to the scarcity of food in higher elevations, the native critters have to be more aggressive to find sustenance. Dealing with these pests will require innovation and strong defenses on your part.

Some of the more common pests include grasshoppers, cabbage worms, root maggots, raccoons, deer, and rabbits. To combat the insects, you can use Semaspore, which is a naturally occurring pathogen that will only affect grasshoppers.

As for cabbage worms, they will require you to pick them by hand when they are in the caterpillar stage.

You can also release parasitic wasps into your garden as a deterrent, while root maggots can be deterred by the plastic covers mentioned earlier. Fending off deer, raccoons, and rabbits can be trickier, however. Consider these options to keep them at bay:

  • For deer, a tall, sturdy fence works wonders.
  • Raccoons and rabbits can be deterred if you raise an outdoor dog.
  • Smaller animals like raccoons and rabbits can also be caught using traps, with plenty of catch and release options available.

Indoor Gardening Is an Option

If growing plants outdoors is too tedious in your location, you can consider indoor growing. This will likely be considerably more expensive since you will need significantly more equipment, including:

  • Grow lights
  • Suitable containers
  • A watering system
  • Enriched soil

More than that, even though the plants will be indoors, you will still have to contend with pests. There is also the increased electric bill due to needing to run the lights, potentially at all times.

If indoor gardening throughout the season is not your thing, it is still advisable to start your seedlings indoors, allowing you more time for your growing season. Seedlings that are germinated and started indoors will have a higher chance of surviving in the outdoors.

Transplanting

When you start your seeds indoors, they are completing a part of the plant life cycle in a safe space while it is still too cold and wet outside for them to survive. However, after a certain point, you are going to have to transplant them outdoors. Keep these steps in mind:

  • Ensure the roots and soil are well watered before moving them
  • The hole should be twice as wide as the roots of the plant
  • Gently pat the soil once the plant is buried, careful not to be too rough

If you are transplanting perennials, indoor growing will allow them to grow larger during their first season, and the increased growth will prove beneficial for future winter survival rates in the following seasons. Transplanted perennials may also bloom in the first year if they are transplanted, which is uncommon for non-transplanted perennials.

Irrigation

The rain varies significantly depending on your geographical location. Rain statistics are another topic that will help you determine what type of equipment to purchase if documented in your journal.

If you notice that you have had adequate rain during the growing season that tapers off toward fall, you may not need additional irrigation.

One of the main reasons to irrigate is to prevent drought stress in the mid-summer growing season if you are in a warmer climate. If you are in a colder climate, the likelihood of requiring irrigation is lessened unless you notice an uncharacteristic drought. Make sure you have a list of your plants’ specific water needs.

Season Extenders

This term refers to a variety of techniques used to increase the otherwise short growing season you will encounter in higher elevations and includes greenhouses, tunnels and row covers, hot caps, and sprinkler irrigation.

These season extenders will also protect your plants from the regular frosts that occur in the spring, fall, and sometimes even the summer months, depending on your location.

Greenhouses

Greenhouses are one type of season extender that can provide a substantial benefit to your crops. They are also something you can do yourself with a bit of effort, and they come in various forms, mainly depending on size and material used. A few common materials are:

  • Glass
  • Fiberglass
  • Plastic

Greenhouses can be heated or unheated, with the decision to heat your greenhouse depending on your location, goals, and budget.

Even an unheated greenhouse can allow you to grow a variety of vegetables well beyond the growing season, and a heated greenhouse will allow you to grow plants even into the winter season.

Tunnels and Row Covers

Fabric row covers are another efficient and cheap way to protect your garden from frosts and some pests. These are set up by installing hoops over your rows and laying the cover over them to create a small tunnel.

This method’s efficiency is increased if you simultaneously use black plastic mulch around your plants.

Check out out Recommended Row Covers

These tunnels will act as a small greenhouse, keeping your plants warm during the winter. However, you will need to keep an eye out for damage from the higher winds you will likely encounter at higher elevations.

Additionally, during the summer, you may need to consider the increased temperatures and create openings in the tunnel to vent hot air.

Hot Caps

These are inexpensive DIY solutions that can be used for individual plants, primarily to protect against frost in the spring. Think of a hot cap as a miniature greenhouse for a single plant.

While you can purchase hot caps from a store, it is also possible to make them yourself from things easily found around the house.

  • Milk Jugs
  • Plastic Cups
  • Styrofoam Cups

If you cut out the bottom of a milk jug, you can place it over a larger plant in the spring, protecting it against frost for up to several weeks. For smaller plants, a plastic or styrofoam cup will do just fine.

Sprinkler Irrigation

This technique may seem counter-intuitive, but it has proven to work. If you use an overhead sprinkler to apply water to plants, the ice-coated plants will not freeze.

To do this properly, you must apply the water before the temperature drops below freezing and keep the sprinkler on until the ice has completely melted in the morning.

The water turning into ice lets off heat, which prevents the plants from freezing. Do not use this technique if the temperature is going to fall below freezing for consecutive nights, as the oversaturation may damage the root systems of your plants.

Robert Sampson

I'm Robert Sampson and I live in Colorado where I spend a lot of time in the backyard with my family either grilling, playing games and sports, or working on a project to make our backyard a better place to be.

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