A look at how we use a string trellis system in our garden to guide indeterminate tomato plants upward. Plus, what is the difference between determinate and indeterminate tomatoes, why it matters, and companion planting.
This week is planting week. The last frost date happened this week. The rain has stopped. I can see the sun. The stars are aligning, and it’s time to get these seedlings in the ground. The first to hit the dirt were lettuce seeds, which went directly in the dirt, but after that, we started looking to tomatoes. I like getting them in as early as possible so I can start benefiting from them as soon as possible.
Last year we made a few changes to our tomato-growing strategy. It had actually been a 10-month process, but we consistently had issues with the tomatoes outgrowing their cages. I bought bigger cages. The tomatoes grew beyond that. I ended up with crowded tomatoes and not a lot of fruit for how large they were.
That same season I had made a visit to the Cascadian Farm home farm in Washington state and discussed their organic tomato-growing methods. I was smitten. The tomatoes grew proud and tall in nice, neat rows. I went home and demanded that we do the same the following year. So we did.
Determinate vs. Indeterminate Tomatoes
Determinate: These varieties of plants will grow large like a bush with their height capping off around four feet, making them suitable for tomato cages and container gardening. They should not be pruned or suckered, as it will reduce rather than increase the crop. Their fruit will all be ready around or near the same time. They are great for canning because you get a large crop all at once. Look at the maturity days for an idea of when they’ll be ready to harvest.
Indeterminate: These tomato varieties grow like a vine. They can reach well over 5 feet tall. Our tomatoes last year were around 7 feet each. They’ll need to be staked, caged or trellised to support their weight, and the fruit will continue to bloom and produce as the plant grows until it is killed by frost. New growth can be pruned or suckered off to encourage fruit production. (Most heirloom varieties are indeterminate.)
A String Trellis for Indeterminate Tomatoes
To be clear: This is not the only way to string tomatoes, and it is not the only way to grow them on a trellis. However, this is what’s been working for us. We gave it a season’s trial, and we were rewarded with a cleaner garden, healthy plants, and plenty of tomatoes that have lasted us all year.
All we did was build a frame to hang over the tomato plants. Our frame leans back slightly, but you could also use a regular A-frame and have the strings straight up and down. A few eye bolts hold a length of garden twine taught along the bottom. Then we run strings of twine up to eye bolts at the top. Each string will have one tomato plant at the base, and we’ll use tomato clips to secure the plant to the string.
Once the trellis is in place, plant the tomatoes at the base of the string. Small hands are good for this.
This is the style of tomato clip we use. As the tomatoes grow, we snap the clip to the garden twine string where we want to secure the plant. The string is held in place, and the tomato fits into the opening. There’s no danger of damage to the plant, and I don’t have to bend and twist the plant around the string, which is a benefit to me.
What to Plant Near Your Tomatoes
Did you know that what you plant in front of your tomatoes can help or hinder the tomatoes and the other plant? Practicing a bit of companion planting can increase yields and help deter bad pests and attract good bugs (good bugs eat bad bugs). Organic farmers have been doing it forever, and you should, too. Here are a few things that you might consider planting in the shadow of your tomatoes:
- Onions and Chives
- Spinach, Lettuce, Arugula
- Nasturtium and Marigolds
Avoid planting these near your tomatoes:
- Black Walnut
- Brassicas (cauliflower, broccoli, kohlrabi)
So, for the foreseeable future, our tomatoes will be shifted between the raised beds this way. It works for us. If I had to change, I’d probably move to a system of bamboo stakes. Have you had success with tomatoes in the past? What kind of support system did you use for indeterminate plants?