A traditional starting point for training climbers on walls and fences is a system of tensioned horizontal wires. Ideally these wires should provide a permanent structure that needs little maintenance over the years, whilst creating a firm fixing for tendrils, shoots, branches and canes to be attached to. In this post I am looking at the best solution I have found so far: the Gripple Trellis System.
In the above shot you can see three horizontal wires spaced about 1ft (30cm) apart vertically, attached to the fence posts with screw eyes every 6ft (1.8m). The bamboo canes along which the fig is being trained are then attached to the wires where they cross using wire twists or twine. Finally the branches of the fig are attached to the canes with adjustable ties.
For such a set up to be successful, the wires need to provide a permanent and reliable support, whereas the canes and branches should be able to be adjusted each year as the training progresses. In the photo above, the wires are over 10 years old and as good as new, whereas this is the second trained fruit tree I have had in this spot (the first – a plum – suckered too much and started destroying the fence and path!)
The point is that you want to invest in a good support system that will last. This is what I use:
Gripple Nylon Trellis System
The Gripple system (see their website here) consists of stout nylon wire along with a clever tensioning block called the Tensulator (TM!). These two parts are the key to this system’s success as I will explain.
Nylon vs Galvanised Steel
Before discovering Gripple I used traditional galvanised wire. This was the only recognised method of wiring walls and fences fifteen years ago, as all the gardening books of the day will attest.
There are, however, many problems with galvanised steel wire which the Gripple system overcomes. This nylon wire is reinforced with fibreglass, and is strong enough to support up to 100kg – more than enough for anything I’ve needed so far!
Here are some side by side comparisons of the problems I have experienced as an amateur gardener, and the benefits of the Gripple nylon wire:
|Galvanised Wire||Gripple Nylon Wire|
|Hard to place under tension.||Easy to tension by hand with proprietary Tensulator block|
|Difficult to tie off. Folding back on itself and twisting the ends together allows creep.||The tensioning block allows simple tying off at the end of a run|
|Has little elasticity and tends to deform permanently with perpendicular force (e.g. ladder)||Has a high elastic limit, so tends to spring back into place without permanent deformation|
|Is difficult to adjust and re-tension||Easy to increase tension by hand. Fairly easy or loosen, remove or reroute|
|Has sharp ends when cut||Cut ends are much less sharp|
|Loses considerable strength if bent through sharp angles||Maintains strength even when pulled through very tight angles|
|Eventually goes rusty||Cannot rust. UV stabilised. Guaranteed for 15 years.|
The main downside of the Gripple nylon wire is that you have to be careful when using secateurs close to it as it is possible to cut it accidentally. I have done this a couple of times, but after cursing myself, have found it easy to fix or replace.
Galvanised wire systems are possibly more suited to commercial installations such as vineyards, where special tensioning tools and fixings make more sense financially.
The incredible Tensulator
What makes the Gripple system such a success is this canny little fitting:
The Tensulator is a small plastic block designed to work with the Gripple nylon wire. It’s clever design allows the nylon to easily pass though, but a non-return mechanism stops it slipping back, thus maintaining tension. I have used two dozen of these over the years and they have never let me down; the one-way grip mechanism has proved very durable and reliable.
Below are a couple of configurations for using it. First (top image), at the end of a run, thread the wire through the Tensulator one direction (1) then around your end fixing (2), back through the Tensulator’s second channel. Then to tighten, pull the loose end whilst holding the Tensulator until you get the tension you want (3).
The downside to the first configuration is that you will need two Tensulators – one at each end – per horizontal run. I have arranged most of my wires using the second configuration shown above. By creating a large loop two horizontal runs require only a single Tensulator. This saves a lot of time and money.
Here are the two configurations in action in my garden:
When using the large loop configuration, I tend to place the Tensulator in the vertical section of the loop as it is out of the way, but easy to get to. This is shown in the right hand photo above.
In either case I like to leave a good length of loose end. This makes it easier to get hold of if you want to increase the tension later.
Reversing the process
There will be times when you need to undo a Tensulator, and pull the wire back through, but the non-reverse mechanism prevents this. It happened to me when I finished a large loop run, only to discover I’d forgotten to thread it through one screw eye. Luckily, the design of the Tensulator makes this possible, although it is a little fiddly.
Step 1. With a narrow blade screwdriver, push in the lugs on both sides as indicate.
Step 2. Ease out the plug with it’s stainless steel retaining spring.
Step 3. tap out the knurled ceramic wheel. This is the little beast that provides the jamming mechanism when the nylon tries to move backwards. Take care not to lose it.
You can now slide the nylon wire backwards to remove it. Once you have the wire out of the Tensulator pop the parts back together and it’s ready to go again. Neat eh?
Hammer-in ‘vine eyes’ sold in most garden centres are a waste of time: they bend too easily, rust and can’t be adjusted. I use screw eyes for supporting my wires on walls (with rawl plugs) and on fences (after drilling a pilot hole).
There are many variations of screw eye available and you need to think about what your needs are before you jump in. This is important as they are difficult to change later without removing the whole wire trellis and any plants that have grown up it.
Stainless steel fixings are the most expensive, but the only long-term solution if you can’t abide rust. Zinc plated eyes will rust in one or two years. Galvanised fixings are a good compromise, staying rust-free for 5 to 10 years or longer. I have had to search on line to get the eyes I want – the DIY stores cater for the low end of the market and are unlikely to be substantial enough. Some of the eyes I have used have been 6in long 5mm shaft.
Length and thickness
An important consideration is how far your wires need to stand clear from the wall or posts. Generally plants do better with good air circulation behind them. For trained fruit a good 3 to 6 inches is a minimum.
With fences this does not necessarily require fixings that protrude this far, as the fence panels are often set back from the posts giving you additional depth. Also, as trained branches are usually attached to canes which are themselves tied to the horizontal wires, they tend to sit an inch or two forward. On the downside, longer fixings experience more leverage, requiring thicker screws.
The end fixings take the most lateral strain. If you get the wrong spec. screw eye here they will bend as you tighten the wires with the Tensulator. There are a couple of options here:
(1) make sure you have suitably strong fixings at the ends
There are proprietary (and expensive) fixings designed to take lateral strain. I’ve never used them, as the ones I’ve looked at always introduced additional problems, or would only work in a limited number of situations. I prefer to use simple, easily available fixings, but use them smartly. This starts with making sure you buy suitably stout eyes. 5mm diameter shafts should be a minimum. The common 3 and 4mm variety sold in many garden centres are not up to the job.
Screw eyes can take a greater force when their shaft is shortened. However, we often want our wires to stand off further than this, so what’s the solution? In my greenhouse I screwed the end screw eyes in deep, but placed longer ones near them to hold the wire further away from the wall.
(2) Try to arrange the end fixings to take the strain ‘end on’.
When the force on a screw eye acts sideways it produces considerable leverage, especially if the shaft is long, which can cause them to bend. Arranging the eye so that the force is parallel to the shaft prevents this and allows the tension levels we want.
For this arrangement to be possible I have found it helpful to bolt a second post to the front of the end posts. You can see this in action along the fence below. The additional post you can see here is placed
This method also works well for open fences, where wires run between posts such as you may see in a vineyard, or as here where I have trained a cooking apple on an open fence:
Tips and Tricks
When puttiing in screw eyes you quickly learn that that a pilot hole is essential. Don’t make it too tight as you will exhaust yourself before you get to the forth eye. Here are a couple of tricks to make it quicker and easier.
LEFT: Use a screwdriver to give more leverage while putting in the screw eye.
RIGHT: Use a hook in a power drill to make driving screw eyes in easy peasy. Take care though, as if you go too fast the torque can bend the hook out of shape pretty quickly.
Here is a video from the manufacturers that shows the basic ideas in action
The best place to start is with the manufacturers website: gripplegarden.com.
Here is a screenshot from their site on 27/May/2017 of the products I have used.
I have purchased each of these and they have all been excellent. The screw eyes are the weakest element, but the bulk packs have been great value. Overall a five star system!