Season Extension: Ventilation & Heating

To make your greenhouse more of a year round functioning entity, there are two main areas in which you have to make the structure more efficient-Heating and Ventilation.

1. Heating is your biggest expense for the winter so retaining heat is a priority.

The easiest way to retain heat in your greenhouse is to install a double poly cover with air in between. A small squirrel cage blower attached to the inside layer of plastic aids in maintaining air between layers.

The more dead air space between these layers you can create, the closer you will be to achieving a 30% reduction in heat loss. Holes will result in air movement and therefore less efficiency. 3″-5″ consistent space is ideal. It is a given that you would have less then that around the edges and over the ridge.

Double plastic will have a considerably longer life span. It is important to realize that as plastic gets older, the light transmission will be reduced which will reduce production.

Infrared plastic (IR poly) does further reduce heat loss and increase light diffusion so it can also be a consideration when looking for ways to reduce heating costs.

2. Ventilation is also one of your biggest considerations for the warmer times of the year. Ventilation can be done through forced or mechanical methods or passive through vents or roll up sides.

Vents are extremely effective since they can be placed higher up where the heat needs to be expelled. Mechanical ventilation is more costly both up front and to operate but it is easier to control since it is attached to a thermostat. For mechanical ventilation to be effective, it needs to be sized and located properly.

Roll up sides are less costly and simpler to install but are restricted by the fact that you have to be there to open and to close.

Climate control is especially challenging in the spring and the fall since most days you will have the need for both ventilating and heating.

One area that you need to be especially aware of is stagnant air. Without proper air movement, circulation and exchanging, stagnant air can cause many different types of diseases. It is important to understand what your plants require

Check out Norm’s overview of Forced Ventilation in this weeks Coffee Time with Norm chat

Coffee Time with Norm: Starting Soon!

Our weekly meet and greet chat is happening again this week, (STARTING in 15 min!) and we hope every week Wednesdays at 9am EST. We hope you can join us!

Today Norm will be covering Ventilation, and time permitting anchoring as well. You will be recorded if you join, but can choose to disable your camera if you are not comfortable having the recording posted on social media.

Join Zoom Meeting
https://us02web.zoom.us/j/83325248870?pwd=WkxKakRDakg4SzIyUVMzTlR2YXErQT09
Meeting ID: 833 2524 8870
Passcode: 5WBcJw

Join us online every Wednesday morning on Zoom to connect, chat, and find solutions to challenges you may have.
Since we aren’t able to get out to trade shows this year, we decided to host this quick weekly check in to connect and say hello!
Norm will be available to answer any questions you may have. You may also send them in advance to multisheltersales@gmail.com and we will answer them “live” on zoom.
We know you’re busy with your business too, so if you send in a question and can’t make it live, don’t worry, we will post a recording on Facebook and YouTube after the event.
Come out and connect, no matter which side of the country you’re on! this allows us to see everyone face to face that we may not normally get to because of distance. we look forward to having you join us in our new weekly special event.
Please note this is a time for connection, brainstorming solutions to your challenges, learning some information about structures and other questions. If you have a question about an order, or would like a quote, please contact the office separately and we would be happy to help you.
We are excited to have you join us for this new event and we look forward to your questions!
Join Zoom Meeting
https://us02web.zoom.us/j/83325248870?pwd=WkxKakRDakg4SzIyUVMzTlR2YXErQT09
Meeting ID: 833 2524 8870
Passcode: 5WBcJw
Coffee Time with Norm Videos

Season Extension: Hanley Caterpillar Tunnels

The first area to discuss regarding season extension are those structures that are simple enough to disassemble and relocate to another spot-primarily referring to Hanley Caterpillar Tunnels.

The real lure of these buildings is their low cost and simplicity to move. Generally the area is prepared in advance and then the tunnel is moved over the area when the planting is to be done.

Since the original design specified 6′ hoop spacing, the intent was always to remove the cover before risk of heavier snow fall. More often now, growers are going to 5′ spacing (and sometimes 4′) to allow the covers to remain on longer or even permanently.

By having a smaller hoop spacing, it allows the cover to stay on permanently, which allows for a much earlier start in the spring.

The key to the concept of the hanley working is in the rope.

  • The back and forth pattern of the rope resembles the way a person would lace up a boot.
  • Typically there is a spring loaded clip at the base where the rope passes through.
  • Once the rope is fully installed, it is important to tighten it through three passes from end to end.
  • If the rope is not tight enough, the wind will create wiggle and movement sideways.
  • When the plastic is tight enough, it also allows the grower to slide the plastic up the hoop to allow ventilation.

Generally the plastic is about 25′ longer then the tunnel.
This allows the installer to bunch up (pig tail style) the extra poly at both ends between a pair of posts.
It is important to get the plastic as tight as possible lengthwise first.
There must also be a rope from the top of the last hoop to the tie off post.

There are a couple of challenges to consider with the hanley tunnels.

  1. One of these challenges is to create a proper entrance. Typically entrance is achieved by slightly lifting the plastic and ducking underneath.
  2. The other are of challenge is the low shoulder height of the structure. This restricts the use to a couple rows of taller items in the middle and a couple rows of shorter plants along the side. The width of the tunnel does lend itself to three regular size beds.

Once you have learned about the nuances of the hanley tunnels, and asked any questions that come up, you will be better prepared to have these efficient season extenders work for you and your application.

Feel free to look at our Hanley Application page for more information and photos, and give us a call with anything else you require.

We are pleased to have many happy customers these structures are working for, and look forward to you being next!

Check out our new book if you want to know more “So You Want to Buy a Greenhouse…Your Guide to Planning a Greenhouse Purchase”

Norm shared some nostalgia after Coffee Time with Norm this week. Check out his story here: