Supporting tomato plants: how & why to tie up tomato plants

Left to their own devices, many tomato varieties grow indefinitely and require a stake, trellis or tomato cage to support them. Find out why and when it is necessary to tie up or support tomato plants as well as which materials are most suitable for this.

The topic of supporting tomatoes is broad, which leaves plenty of room for you to be creative in terms of what type of climbing aid you want and which material to use. But do all tomatoes need support? Are there different ways of supporting tomato plants? And how do we recognise when our tomatoes need support? Read on to get all of the answers to your questions about supporting tomato plants.

Which tomatoes need supporting?

Apart from some very low-growing dwarf or bush varieties, almost all tomato varieties will need some form of support sooner or later. Most varieties are vining tomatoes, which grow indefinitely and can reach a height of over 250 cm. If they are not tied up, these tomatoes could fall over during the summer, causing them to bend or break due to the weight of their large fruits. If tomatoes lie on the ground, they become susceptible to pests such as slugs and soil-borne diseases like tomato late blight (Phytophthora infestans).

When to support tomato plants

Tomatoes planted from May onwards should ideally be given some kind of support as soon as they are planted. This also prevents damage to the roots and shoots, which could easily occur if the plant is given a tomato cage or trellis at a later date. Supporting tomato plants right from the start also protects them from bad weather and wind gusts. Depending on the size of the young plant and how quickly it grows, you will also need to regularly check on the growing stems and tomato trusses and tie them up if necessary.

Fertilising is just as crucial as supporting and tying tomato plants. We recommend mixing a slow-release fertiliser, such as our Plantura Tomato Food, into the existing soil before filling the planting hole. Over the next three months, soil organisms will slowly break down the fertiliser granules, releasing vital nutrients to the plant’s roots. In summer, apply a lower dose of fertiliser as a top-up to last until the end of the season.

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How to tie up tomato plants

As tomatoes are not climbing plants, they will not naturally cling onto stakes or trellises by themselves, so they need a little help. When tying up tomatoes, take care to not damage any stems. Read on to find out about the different ways of tying up tomato plants and how to keep them upright.

How to support tomato plants with string

It is common practice for farmers growing tomatoes in greenhouses to use string to tie up their plants. It is also possible to use string to support tomatoes under a rain cover or elsewhere in the open, as long as whatever you tie the tomatoes to can bear the weight.

The advantage here is that you can tie the tomato plants to the stake loosely, allowing them to sway a little in the wind and preventing them from breaking. Luckily, tying up tomatoes is a rather easy task. Simply wrap the string around the growing stem and tie it to whatever you are attaching it to.

One downside is that bushy tomatoes with several stems cannot be supported in this manner. In a greenhouse, though, you can tie up double-stemmed tomatoes with two strings. To attach the string to the plant more gently, put a plastic ring around the stem and tie the string to this rather than tying it around the stem directly.

Which string is best for tying up tomatoes? Strong, tear-resistant materials such as nylon or plastic twine will last for several years. However, as these are made of plastic, it is important that they do not wind up in our environment. Other more sustainable and biodegradable alternatives include hemp, sisal, coconut fibre, and jute twine. These may only last for one season, but they are more environmentally-friendly options that you can simply add to your compost heap (together with the plant) at the end of the season.

Supporting tomatoes with stakes or spiral rods

A good alternative to tying up and supporting tomato plants is to use plant stakes made of metal, bamboo, or wood. This involves less effort. Simply insert the stake into the ground, and then secure the plant to it using string, elastic bands, or plant ties. You can stake tomatoes growing in greenhouses, outdoors and in pots. When growing vegetables such as tomatoes or cucumbers in greenhouses, it is common to use a metal spiral stake. These allow the plants to remain upright without having to tie them up.

To tie up tomatoes in pots, insert three or four bamboo sticks into the soil at the pot’s edge, spacing them evenly around the plant. Then, wrap sisal or other twine around the sticks from the bottom to the top, creating a sort of spiral cage so that the stems can lean on the strings if necessary. This is especially suitable for wide-spreading plants with multiple stems, such as wild and bush tomatoes.

When tying tomatoes to stakes, be sure to leave enough space between the plant and stake. This prevents the string from injuring the plant and also allows the stem to become even stronger. As an alternative to tying tomato plants, you can use plastic clips and plant rings that you clip around the stems.

Supporting tomato plants with trellises

Tomatoes grown outdoors are often tied to wooden or metal trellises or climbing frames. A bamboo tomato trellis is not only visually pleasing, but also quite easy to build yourself. The downside is that bamboo is not particularly durable.

Tomatoes supported by trellises are usually grown with only one main stem. To prevent the trusses from breaking off, you can tie them to the horizontal rails.

Larger wall trellises, on the other hand, make it possible to tie up even strongly branched plants. Simply weave the young stems into the structure carefully – there is no need to tie them with string. However, disposing of dead plants at the end of autumn is more challenging here.

Supporting tomato plants with tomato cages

Tomato cages are an excellent way to support your tomatoes growing in pots. They are often cone-shaped with several different sized rings connected by metal rods that form a tower. Alternatively, you can simply bend wire mesh into the shape of a tower and place it around the plant. Tomato cages provide space for the tomato stems to grow in the middle. Depending on the diameter of the metal rings, it is possible to support either the entire plant or just the main stem. Narrow cages are suitable for single-stem plants (indeterminate), whereas wide cages are better for supporting tomato plants with multiple stems (determinate), such as cocktail or cherry tomatoes.

The advantage of this method is that the stems can lean against the metal framework and are only tied up as and when necessary. Tomato cages are also an ideal climbing aid for wild tomatoes with their vigorous growth and multiple stems. Nonetheless, it is essential to install tomato cages or columns right from the start to avoid any possible injuries to the roots or shoots.

Instructions for DIY tomato plant support

Metal tomato supports are great as you can reuse them again and again. However, it is important to thoroughly clean and disinfect the support between uses to avoid disease transmission to new plants. Wooden climbing aids, on the other hand, do not last as long but are cheaper and easier to build.

To build your own tomato support, all you need are some sturdy bamboo or wooden sticks (about 2.5 metres long) and tear-proof twine. Bamboo, hazelnut, or willow sticks are all suitable for building trellises. To do this, insert the long sticks deep into the ground in parallel rows about 50 to 70 cm apart. Tie the sticks together about 15 cm from the top and fasten them to a crossbar for more stability. Attach one tomato plant to each pole or in the middle of the tower use string to tie up the plants to the crossbar. You can build a trellis from wooden slats, using a few screws or nails to hold it together. Overall, building good climbing aids for tomatoes takes very little time and requires only a few materials.

Whether or not you can tie up tomato plants largely depends on how you train the stems. Take a look at our article on pinching out tomato plants to learn some of the different ways you can train your tomato plants. Here you will also find out how to recognise side shoots, known as tomato ‘suckers’, and how to remove these without damaging the plant.