This week I heard something that I haven’t gotten a chance to fact check, but my gut instinct from living in the Gunnison valley tells me that this is right. I heard that if you look back through the temperature records for the Gunnison valley, there have been less than seven days in late July that have never had a frost. Every other day in the year at some point in the past has dropped below freezing. This just highlights how inconsistent and short our growing season can be. This is why season extension is key to trying to garden in the Gunnison Valley. I recently caught up with Robert Johnson to learn a little more about extending this short season that we have. Robert is a self-taught gardener who, through years of trials and experiments, has figured out a way to grow year round in the Gunnison Valley. He seemed like the perfect guy to ask my questions to.
When I first got to Robert’s property, I was immediately blown away by how much of his growing space was in either hoop houses or cold frames. Almost his entire garden was under a hoop house or in a cold frame. While getting a tour of his garden, he explained to me that he got his two massive hoop houses from Walmart when they were trying to throw them away. Walking around his garden I started asking him some questions about techniques he was using to extending his season.
Row cover
The simplest method for season extension would be row cover. In the Gunnison Valley, row cover is a gardeners best friend. This stuff can help keep early and late (as well as mid-season) frosts away. It can protect your plants from pests and shade your plants from the intense sun that we get in the middle of summer. If you don’t already, I would highly recommend getting some row cover for your garden.
Selecting the right breed.
After I asked him the question, he immediately stressed to me the importance of selecting early season breeds of any plant that you are growing in your garden. There are a variety of breeds of every plant. Some of them have shorter days to maturity, and some of are situated better for the cold. Finding the right breed for our climate can be the difference between harvesting from your garden, and watching everything freeze before it’s ready. Here is a list of some of the breeds that Robert is using.
Potatoes: Golden globe and Norkotah.
Brussel sprouts: Jade Cross E.
Peas: Cascadia and Avalanche snow pea.
Acorn Squash: Table Ace and Gold Nugget.
Tomato: 4th of July and Moskvich.
Robert also informed me that ACE hardware does a pretty good job at only getting breeds of plants that will do well in our climate.
Micro climates
A big part of extending your growing season is understanding your garden’s micro climate. Unfortunately, the temperature that they read at the airport, is seldom the actual temperature that you will get at your house. Slight variations in geography, wind exposure, and soil moisture, will all cause slight variations in temperature. Not to mention a thousand other factors. These will most likely only be slight variations, however, a variation of 2-3 degrees can be devastating for your garden on a night that was supposed to 33˚. The best way to figure out your own microclimate is to simply test your own temperature. You can easily compare this to what is being reported for the weather and learn if your garden is going to be colder or warmer than what they are predicting.
Passive solar.
One of the keys to season extension in this valley is storing heat from the sun throughout the day. This can be done in multiple ways such as greenhouses, hoop houses, or cold frames. All of these structures work under the same basic principle of capturing and retaining heat from the sun. We are all familiar with a greenhouse, and most of us would love to have one, but just because you don’t have a greenhouse doesn’t mean that you can do anything. Hoop houses and cold frames are great and easy ways to extend your growing season and could be added to your garden to help you with this growing season.
Cold frame.
A cold frame is essentially a box with two open sides opposite from each other. One of the open sides is placed over your garden, and the other open side is covered with either a glass or plastic. These boxes can be constructed out of just about anything. You could use be a wooden frame, hay bales, cinder blocks, or basically anything that you can stack up into a wall. Robert showed me that for his cold frames, he constructed them with wood that was lined with a foam insulation. He also gave me his secret to building a light fixture into the side of his cold frames which he puts an outdoor incandescent light bulb in. This light bulb can add enough extra heat to your cold house to save your plants on those colder nights. Here is a quick how-to-video on cold frames. You do not have to follow his design directly, but it should give you a good idea of what to do in your own garden.
Hoop house.
Hoop houses might be the easiest structure you can build to extend your growing season, especially if you already have a raised bed. Hoop houses are pretty simple. To construct one, attach PVC to the side of your garden bed and bend it over to the other side if your garden. Do this at multiple places down your garden and attach them all to one PVC pipe that spans the top of your garden bed. This skeletal structure is then covered with either row cover or a thick plastic. Both of these will help to hold heat in the garden. Robert gave me the hint that he uses welded wire mesh instead of PVC pipe for some of his smaller beds. He told me that this mesh wants to hold a rolled up position. It can be unrolled, over the garden, and when it tries to roll back up it will close down on the edges of the garden, creating the structure of a hoop house. Cover it with row cover or thick plastic, and you have an easy hoop house. Here is a quick video that shows how to build an easy hoop house over your garden bed
Both of these are easy ways to build infrastructure that will extend your growing season. But there are some easier tips that you can do to increase the heat in your garden just a bit. Many of us use walls of water on our gardens, but we can also use water bottles or buckets to keep some heat under our row cover at night. We can also put some string lights under our row cover to help keep a little bit of heat in our gardens. Lining the walls of our raised beds with something like cinderblock that will soak up heat during the day and put it out during the evening can help. Regardless of what you are doing to extend your season, if you are growing in a green house or running out to throw row cover over your garden as the snow is falling, there are many things that you can do to extend your season, but you have to be doing something here.