Season Extension Part 1

Over the years our vegetable production has grown, with it some lessons and hardships along the way. The image above shows the Spring 2018 garden, a 24’x32′ space. We’ve learned so much about growing here on our property with this garden. Early frosts, heat waves, too much rain, drought,… we have to be prepared (ode to my boy scout days). We’ll never have control of Mother Nature, but having some ability to protect crops from the climate is a wise investment. To be the sustainable homestead we aim to become we need to take these changes into consideration. Having an ability to protect crops from frosts, rain, wind, etc., is important and why we are considering season extension techniques.

A Little Background.

In the past year we have experienced some typical weather and some very atypical events. Luckily, we’ve lived on our land long enough to notice some reoccurring patterns and record some of the micro climates. One of the first glaring micro climates we noticed was that we live in a frost pocket; our home location and garden plots are located low in a valley surrounded by wooded hills. Cold air and moisture naturally settle in our area and we typically see frosts earlier in the fall and later in the spring. Tender transplants need protection from these frosts and we have already experienced damage in the past with our small gardens. The garden area has good southern exposure with no obstructions but in the heat of summer this can be a drawback. To cope with this we have planted a hedgerow to the west of the gardens to allow for some heat relief late in the days.

Another final consideration is water. Water issues have become noticeable since gardening. On our property, we have no above ground water and only a home well. We need to be conscious of the amount of water we use and try to use more rain/surface water. We use our rain water catchment system we built as much as we can. However, over the past few years, we’ve noticed that there is a 6-8 week period starting around summer solstice where we receive very little rainfall. Our system could only support our small garden for 2 weeks at a time. Around the beginning of Fall we start to see more rain. We typically end up getting a few serious thunderstorms that are capable of strong winds and hail that can cause potential problems. A notable storm this past year produced a microburst with 90mph straight-line winds. The winds caused a few shingles to pull up on our roof but luckily there was no other damage to the home. However, we did lose a dozen tall pines in the woods.

Becoming familiar with your micro-climates and weather patterns are the first step in any permaculture planning process. Permaculture teaches us to observe the environment we live in before taking action. For gardening, our observations and experiences brought to the surface a need for season extension techniques. We would also need to consider permanence and low labor inputs from an efficiency and time standpoint.

Season Extension Techniques.

There are a few season extension techniques to review before moving forward. All of which have their own pros and cons. Most season extension methods involve temporarily constructing, building or installing a shelter over the crops. We wanted to avoid this labor intensive practice. We were looking for a technique with the least maintenance and most opportunity for growth in the future. A thorough pros and cons list was developed and eventually we came to these conclusions for our specific situation.

Row Covers: Pros – Cheaper than other options, quick to construct. Cons – Time consuming to manage, limited frost protection, collapse or tear under snow/ice, reconstructed yearly.
Hoop Houses/Caterpillar Tunnels: Pros – Quicker setup and cheaper then following high tunnel option. Cons – limited sizing, semi-permanent structure, thinner wall pipe (wind/load concerns), ventilation is manual, concerns around insect infiltration.
High Tunnels: Pros – structures are permanent, more sizing options, opportunities to use the space for various gardening activities. easy access and greater protection from weather. Cons – Large structure, more upfront cost, longer construction time, more knowledge required for construction.

The Decision.

Our location has challenges with frost and at minimum we need protection. Through research, we noticed that most small farms admittedly wished they had started with a high tunnel. Since we do not plan on moving our structures (limited space) once completed, the permanence of a high tunnel was not a drawback. The added strength and ability to be heated in the future were big positives of a high tunnel for us. A high tunnel also solves our rodent(vole) problem with the addition of buried flashing or hardware cloth to exclude them from the space(not fun watching a carrot disappear into the ground).

During the process of figuring out what season extension technique to use, we also needed to figure out what would fit on the space available. We have limits on space and could not go any wider than 30 feet and no longer than 70 feet. Row covers were automatically crossed off the list. We’ve read and heard that most small farms end up transitioning to a caterpillar tunnel or larger structure quite quickly. Most caterpillar tunnels come in 14 feet widths and we would need two structures side by side. We would only need to build one high tunnel structure to cover our 30 foot width.

Ultimately, our decision was based on future plans and going with a high tunnel was the right decision for us. We could shelter 8 permanent beds under a 30 foot wide tunnel. The permanent beds would need to be no longer than 50 feet long. This amount of space allows more room to expand in the future and room to experiment with different crops.

The High Tunnel/Hoop House

After making the decision to build a high tunnel, there were two ways to proceed: purchase new or used. New high tunnels are quite expensive and cost well beyond $7,000. Buying used would potentially cut the cost in half depending on how thrifty you could be. High tunnels are essentially simplified greenhouses, so searching for used greenhouses is definitely an option. Our decision was simple – buy used. We aren’t a fancy farm with deep pockets nor are we willing to sink ourselves into debt to start this venture. Choosing to find a used high tunnel was the best option for us. It would save us money and our background with DIY projects left us with the skills needed to complete the project.

It took months of looking to find a used greenhouse frame that was only an hour drive away. It turns out that we found a seller who bought two 200 foot long greenhouses. After taking some measurements and talking it over we decided to pick up 60 feet of the structure. The 60 foot length allows us a bit of extra room to potentially grow micro greens or seedlings. We chose to go with a stronger frame orientation so that every other hoop has a truss and hoops are spaced at 4 feet. This is a total of 16 hoops with 7 of those being trusses (trusses are not used on the first and last hoops) for a 60 foot structure.

After getting the frame home we started planning and there were still a lot of pieces that were needed to complete the structure. We needed to add two purlins, ground posts, end walls, greenhouse plastic, wiggle wire, base boards and side rails. In the meantime, we started staking out the area and THAT is when we realized just how big a 30’ x 60’ structure was going to be.