There are so many variables when it comes to working out the best technique for trellising tomatoes. We can learn a lot from people who grow them for a living.
Opinions on the best way to trellis your tomatoes are many and varied. And for lots of gardeners, experimenting with different methods each year is all part of the fun of tomato season. But there are people who have grown more tomatoes in the last decade than many of us will grow in our entire lifetime. People who, depending on their climate, conditions and required results, have perfected tomato trellising techniques.
Know Your Plant
Tomato plants fall under one of two types: determinate or indeterminate. Before you can think about your trellising options, it’s important to know which of the two you’re looking to support. Determinate tomatoes, sometimes described as bushing tomatoes, will reach a certain height – usually around a metre or so – and stop growing. They’ll throw one flush of flowers at more or less the same time and produce all of their fruit over a short period. And while they will benefit from support, it’s not essential, so better suited to smaller spaces.
Indeterminate plants – or vine tomatoes – will continue to grow and continue to produce flowers and fruit right throughout the growing season. They require regular maintenance and support to ensure high yields.
Left to their own devices, indeterminate tomatoes would produce many growing tips and lateral branches which the plant would spend a lot of energy producing stems and leaves for. Not only is it energy which is better off being redirected into producing beautiful fruit, but all those leaves and branches restrict both airflow and light, which increases risk of pest and disease.
It means that pruning your vine tomatoes is as equally important as trellising, and more often than not, the technique of one will usually be defined by the other.
A Central String
Fraser Bayley and his partner of 22 years Kirsti Wilkinson run Old Mill Road, a bio farm on the south coast of New South Wales. While tomatoes make up just a small percentage of what their farm produces, the pair grow up to 400 indeterminate tomato plants each season. This year they have 240 plants of commercial varieties as well as 160 heirlooms, which all require trellising.
For them, the risk of fruit fly and birds have forced them to grow their tomatoes in a poly tunnel, something made easier due to the fact that tomatoes are largely self pollinating. Because space is finite, and the tunnels themselves offer the infrastructure to do so, the pair train their tomatoes high up strings which are attached to cross wires running along the length of the tunnels.
‘To the wire we hook a string – we use a commercial product called a Tomahook, which is a length of string wrapped around a piece of wire – and you can lower the string and raise the string without having to tie knots,’ Fraser explains. ‘And then the plant itself gets clipped to the string by a tomato clip. You can also weave the tomato around the string – we use clips because it’s quicker.’
The clips Fraser refers to are plastic and circular and they clamp on the string itself and close loosely around the stem which ensures the plant is free to grow and expand without being hindered or damaged by the clip.
Clockwise from top: Indoors, where there’s less airflow and a lower risk of sun scald, Fraser and Kirsti prune regularly; Cheryl uses lots of companion flowers; Kirsti mulches heavily, even though poly tunnels tend to slow evaporation. Photos By Robyn Rosenfeldt
An External Cage
On Victoria’s Mornington Peninsula, owner of Daniel’s Run Heirloom Tomatoes Cheryl McGaffin takes a very different approach. Focusing solely on heirloom varieties – many of which she has bred from her extensive catalogue of saved seed dating back to when her grandfather grew heirlooms – and without the threat of fruit fly – Cheryl grows up to 180 plants per season outdoors.
With the luxury of being able to plant with generous spacing and in soil that has the time to be meticulously reconditioned between growing seasons, it was necessity that forced her to create tall and very sturdy cages to facilitate her trellising technique.
‘The cage came from necessity because the tomatoes grew so big – we’re talking eight-, ten-feet tall – they’re trees really, not vines,’ she explains. ‘I couldn’t use string or a florida weave (see breakout), it would just give way.’
With a stake in the middle to support the main stem, the cage is placed over the plant six weeks after it goes in the ground and secured to a star picket using cable ties.
Despite Fraser and Cheryl’s different growing approaches and environments, their pruning techniques are quite similar, at least at the start of the growing season.
Fraser and Kirsti prune to two main leaders, or growing tips, and train the two stems in a vee shape up two strings. Due to the higher humidity experienced inside a plastic-covered growing tunnel, they’ll spend up to an hour each morning pinching out laterals and ‘stringing’ their vines to ensure there’s plenty of airflow.
‘In the tunnels, we prune the tomatoes up to 400 mm off the ground,’ says Fraser. ‘That’s mostly for airflow, but it’s also for our ergonomics, being able to pick tomatoes without constantly bending down.’
Cheryl opts for a less intensive approach. ‘I do shape them initially for the first six or seven weeks, and I prune to three main leaders,’ she says. ‘The third one’s just a safety thing in case something happens to one of the leaders in our unpredictable spring weather.
‘Because you’ve got a cage system, you can sort of fan it out, a bit like a fruit tree. One main leader goes up the central stake, and then two just placed evenly around the cage and secured to it using fabric ties.’
Plenty of spacing between her plants helps, too. ‘I don’t have any problems with fungal diseases or anything like that, I use generous spacing. A lot of market gardeners are a foot apart or a foot and a half apart, I’m a metre and a half apart, so the air just whistles through them.
‘I’ll probably do a bit of pruning, taking some suckers out to improve airflow and light and that sort of thing, but by the time they start to produce, there’s just too much to prune, so they just do their own thing.
‘As long as they don’t flop over the top of the cage, they double up on themselves and you don’t get good airflow. That’s why our cages are so tall. I’ll take a least a foot off the top several times a year.’
Unsurprisingly, when Fraser and Cheryl are asked to suggest how to grow tomatoes successfully at home, their advice mimics their individual larger-scale techniques. Fraser says you can run a string up to your eaves on the sunny side of the house, but stresses that support of any kind is what’s important.
‘Peg the string to the soil at the base of the plant,’ he says. ‘That’s only really for the beginning, because once the plant’s strong, it’s anchored by its roots. Otherwise, I tie them to something, whatever I’ve got. I might tie them to bamboo sticks, but this year I’ve got an old wroughtiron gate and I’ll just peg that in with a couple of pickets. I like to keep a fair bit of airflow around the tomato, and I’ll just tie it to the gates with a bit of soft cotton twine.
‘Your plant is going to get moved by the wind and people brushing past it and what not, and a hard jute or bailing twine can rub up against the plant and create an issue.’
For Cheryl, the cage system is about balancing good output with the required amount of input.
‘For a home gardener I think they work quite well,’ she offers. ‘It’s better than having to go out and tie and do all of those sorts of things all the time, which is just so intensive. With the cage, once you have the main pruning done, it’s set and forget.’
Fraser says sticking with the basics should ensure home gardeners are getting the best from their tomato plants.
‘Tie them to something, keep the leaves out – I train to two or three leaders, because that’s what I’m used to – but make sure there’s plenty of airflow. And don’t water the plant, water the soil,” he adds, which about reducing the risk of disease. ‘If you’re going to grow a big tomato, it pays to tie it up really well. The wind will pull both the plant and the trellis down if you’re not careful. But if you’ve got it up against a wall, you’re pretty safe.’
Cheryl’s advice is aimed at three things: temptation, diversity and soil.
‘First of all, don’t be greedy. There’s always next year to grow lots more tomatoes,’ she laughs. ‘It’s better to have a smaller, successful crop that requires minimal intervention than an overgrown jungle that’s diseased, that’ll stay in your soil for the next year and cause you more problems.’
Which is not the same advice she gives for adding biodiversity into the bed. ‘Add lots of beneficial flowers and herbs – as many things as you can get in the better,’ she says. ‘Lastly, what a lot of gardeners do, is it’ll come to October and they’ll think it’s nearly time for tomatoes, I better get the bed ready, but they really need to be getting the bed ready in March. They need to be piling on the compost and carbon and nitrogen, so come October you can just plant the tomato in the bed and you won’t really need to do any fertilising.’
HERE’S A TRELLISING SYSTEM THAT’S EFFECTIVE FOR BOTH BUSHING AND VINE VARIETIES
This system only works of you’ve got three or more tomatoes planted in rows. Bang in two stakes at either ends of your row, making sure they’re at least as tall as you expect the plants to grow. Once they reach a height where they require support, secure a length of soft twine around one stake and weave in and out of your plants – in front of the first, behind the second and so on, until you reach the other stake. Loop you twine around the stake a couple of times to ensure it’s tight before returning in the direction you came from, weaving through the row but on the opposite sides of the plants from which you came. Tie off on the first stake and repeat the process up the stakes as your plants grow.