While not as productive as staked tomato plants growing tomatoes on a horizontal trellis involves less work. It is the ideal way to grow tomato plants for veggie gardeners who struggle to keep up with the regular pruning of laterals that conventional methods of growing tomatoes require.
Tomatoes can be grown on the ground, especially bush varieties such as KY1, however growing them on the ground presents problems. There is a high likelihood of fruit touching the ground, potentially leading to rot and disease problems. Rats (common eaters of fruit, including tomatoes) are more likely to eat tomatoes on a ground grown tomato plant than ones supported with stakes. Ground grown tomato plants also have less airflow under them than plants grown on a horizontal trellis or supported with stakes. Good airflow aids in the ripening of fruit and reduces the likelihood of fungal diseases.
Growing tomato plants on a horizontal trellis removes a lot of the disease and airflow problems associated with growing them on the ground. The other big advantage is that it involves less pruning than staked tomato plants and virtually no tying up of laterals.
The main disadvantage is that only half the number of tomato plants can be grown in a given area compared to staked tomato plants.
Horizontal trellises can be built using a variety of materials. However, these instructions are based on my horizontal trellis frame, which is made from reinforced concrete mesh with 20 cm square holes. The advantage of using reinforced concrete mesh is that it is self supporting, making it quicker and easier to set up and dismantle.
- CUT A SECTION OF MESH THAT IS NO WIDER THAN THE WIDTH OF A RAISED BED AND HOWEVER LONG IS PRACTICABLE
This will be the horizontal section. Mine is 1.2 metres wide by 2.4 metres long.
- CUT TWO SECTIONS OF MESH 40 CM WIDE AND THE SAME LENGHT AS THE HORIZONTAL SECTION
These will be used to support the horizontal section above the ground.
- CUT OFF ONE EDGE OF EACH OF THESE 40 CM WIDE STRIPS OF MESH TO CREATE SINGLE RODS ON ONE SIDE
- PLACE THE TWO THIN SECTIONS ABOUT A METRE APART IN AN UPRIGHT POSITION
Drive the ends of the rods 10 cm into the ground to support the uprights vertically.
- PLACE THE HORIZONTAL SECTION ON TOP OF THE TWO VERTICAL SECTIONS
- PLANT A SINGLE ROW OF TOMATO PLANTS IN THE CENTRE OF THE BED
5 to 6 plants for a 2.4 metre long trellis. When I first used the horizontal trellis method I planted two rows of tomato plants but found that this created overcrowding problems.
- CUT ALL LATERALS OFF THE MAIN STEMS UNTIL THE TOPS OF THE PLANTS ARE ABOVE THE LEVEL OF THE MESH
- LEAVE THE LATERALS ABOVE THE MESH TO GROW FREELY OVER THE TOP
Only pruning them when they begin to grow off the edge of the trellis.
An alternative to reinforced concrete mesh is to use soft wire mesh nailed onto a wooden frame. Bricks can be used to create the vertical supports, in fact the old gardener I originally got the idea from used bricks. He would start with one brick in each corner and then, as the tomato plants grew bigger, jack up the frame to a height of three bricks.
Cut away illustration of how to prune and train tomato plants growing on a horizontal trellis.
The horizontal reinforced concrete mesh trellis held in place 30 centimetres above the ground with the two vertical sections of mesh.
Note that this photo was taken in 2007. As I no longer use the horizontal trellis method and did not take many photos of the garden back then I have almost no photos of a horizontal trellis in use. While this photo shows two rows of tomato plants, I mostly planted only one row as I found that two rows would overcrowd the trellis. However, I have no photos of a horizontal trellis with only a single row of tomato plants, nor do I have any photos of when the plants were mature.
The simplest and most cost effective way to provide trellises to grow vegetables on is to use reinforced concrete mesh as it is strong enough to be self supporting.
LEFT: Section of reinforced concrete mesh used to create the vertical support for the horizontal trellis. It consists of two rows of 20 cm wide square mesh with the bottom edge cut off. The pins that this cut off edge creates are driven about 10 cm into the ground, which provides enough support to keep the mesh upright. RIGHT: Section of the mesh used as the horizontal section.
Another advantage of a horizontal tomato trellis is that it makes an ideal frame to protect early season tomato plants from late frosts. This photo was taken in 2020. While I no longer grow tomato plants using the horizontal trellis method I still use the frame to protect early season tomato plants.
Because it is less space efficient I no longer grow tomato plants using the horizontal trellis method. However, it is great for those gardeners who struggle to keep up with the pruning and tying back of laterals.