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”

Important Note About Freight Costs from Norm

Featured

With sudden skyrocketing fuel prices we can no longer guarantee freight costs. Any freight or courier quotes, at this point are an educated guess and would have to be confirmed at the time of ordering.

This applies to anything that has been quoted in the last 30 days as well.

We will be carefully monitoring all freight quotes from our suppliers and definitely favour those that give us the most stable pricing.

We hope that is a short-term problem. We also hope for a peaceful resolution to the problems that are behind this volatility.

We will keep you posted.

Norm

Wind braces for structures

There is no dispute on the need for wind braces on any structure. There is often confusion on how and when those braces need to be installed.

The sooner that some sort of bracing is installed on a building, the easier it is to maintain plumb or vertical. For this reason, we stress the importance of tying off a building, both ways, as soon as the first section has been erected.

One detail that many overlooks are the total surface area of the hoops. It does not take very long to have the combined surface of a 4’x8’ sheet of plywood. For this reason, it is important to not rely for an extended period on your initial tie-down ropes as your “bracing”. There have been instances where the combined surface area of the hoops is more than the entire gable end.

If you are doing a long building with long hoops, i.e. 30’ wide, it would be wise to install the bracing before the whole structure is assembled.

Wind bracing can be installed in two directions, one goes away from the end wall and one goes toward the end wall. Both ways are acceptable, provided that you do both. If you install them toward the end at one end, you must do the same at the other end. By doing the same concept at each end, you are essentially holding things in opposite directions.

When bracing goes away from the end, the load is referred to as “tensile load”. Cable is often used for this. The cable and the clamps used must be rated against stretching and breaking. This is a convenient system since you are not limited by a precise measurement. When using this system, it is important to end up at the ground, in the 4 corners.

When bracing goes toward the end, the load is referred to as “compression load”. Round tubing with flattened ends is most often used. It is important to make sure that the tubing is strong enough as to not bend as it is being compressed. This is the method which has been used the longest since the instinctive way to brace something it to “prop something against it”.

With either method of bracing, where you start and end is very important. For bracing to be effective, you must start at a point that is connected to the whole structure. This would be either the ridge or a row of purlins. Starting at a mid point of a hoop will give little reinforcement since the hoop can flex from side to side. The closer that bracing goes at 45 degree angle, the stronger it will be.

In the case of longer hoops with multiple rows of purlins, it is advisable to have a series of shorter braces than one long one. This means you would start at a certain hoop/purlin connection and go down and over for 3 or 4 hoops and anchor at that hoop/purlin connection. Go over to the same hoop you did the first brace on and repeat the process from the lower purlin. You would then be going down to the base or the next row of purlins. Remember that if at one end, if you are going left to right, on the other end you go right to left.

Where ever you end up, it is wise to have extra anchoring at that point.

For extra clarification, please watch our “installing wind braces” video on the website.

Hanley Installation – from our customers

We found a very helpful video from our customers we thought we would share about building a Hanley, check it out!

February Features! *Winter and Your Structures*

We have a number of resources on our website to help you with taking care of our structure over winter. We have compiled a list of “Greatest Hits” below, that you can review at your leisure and please don’t hesitate to contact us with any questions if you are unsure or can’t find what you’re looking for. We are always happy to help.

The best place to start is the Winter Care Pages in our instruction manual.

We also have: Winter FAQs

Video: Norm explains the situations where you would need to remove snow from a Greenhouse or Storage Building and how to do it safely

Winter Care & Maintenance
Important notes for various situations
Our structures are designed in a gothic shape with a slippery cover to be lightweight and snow resistant. This encourages the snow to slide off quickly. This is not an industrial high snow load building….

Weather Cautions
These buildings are not industrial grade shelters and, as such, some caution must be exercised under some winter storm conditions….

Winter Storm & Your Structures
Many areas have been hit with freezing rain today and even though it has generally not been enough to warrant concern for the structures, it is a good time to recap some common things when dealing with ice on buildings….

Retightening a Loose Structure Cover
Re-tightening a cover does not have to be done in one day. Taking a short cut will leave you with more wrinkles. Areas with wrinkles will flutter more and cause stress points.
This will also cause the cover to deteriorate quicker……

Temporary Fix for a Loose Cover
There are a number of instances where a cover will need to be installed in less than ideal conditions. This can be either be on a windy day or in the cold (-10C or worse) and the job simply can not wait.

Season Extension: 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…..

Happy Valentine’s Day and Family Day! We hope you and your family are staying warm, and getting excited for the upcoming spring and growing season! We look forward to working with you on your projects in 2021!

What are the considerations for growing over winter?

Heating, interior tunnels, air circulation, humidity control

When someone is intending to grow in a plastic covered greenhouse over winter, the first order of business is to put a double layer of plastic with air between.

This cushion of air acts as insulation and will reduce heat loss by about 30%. A secondary benefit from this cushion of air is that it reduces condensation in the greenhouse dramatically.

Even if you are not going to heat the greenhouse, it makes sense to put the extra layer of cover with air between since it will provide a significant extra margin for cold.

The small fan which puts the air between the layers is made to work against pressure. It can not “over fill” the cavity.

When installing the second layer of plastic, it is not pulled tight. This allows the second layer to puff up to about 10 cm which is the optimum space.

It is the dead air space that creates the insulation value. If the air is moving, you will not have optimum efficiency. This is the reason it is important to be vigilant about patching any holes in the plastic when they occur.

Especially if your intention is to grow without heating, you could benefit from installing and using small interior tunnels. These tunnels would only be covered during severe weather. Since the air volume is small, even the heat from a few light bulbs will make a difference.

Interior air circulation is even more important in the winter time than it is in summer. In the winter time when things are more likely to be closed up, the probability of stagnant air is high.

It is important to monitor the humidity level in your greenhouse as well. Getting rid of excess humidity will cost you some heat, but you are creating a healthier environment for your plants.

If you are using a forced ventilation system for either humidity or heat control in the winter, it is important to have the thermostat close to the incoming air so that things will shut down quickly if the incoming air is extremely cold.

Any heating system which is used in a greenhouse should have a stainless steel heat exchanger and burner. The standard aluminized units simply will not stand up long term in the moist environment of a greenhouse.