How I prune my tomatoes is a popular question and while I was out doing that work yesterday evening, I figured it was high time that I address it here on the site.
There are countless ways to approach tomato culture, all or at least most of which are probably right and good. I am not one to force my methods down anyone’s throat — you are doing it right if it works for you. I’ve experimented with a lot of different methods over the years, sometimes intentionally and sometimes due to neglect (do not underestimate the learning that comes from doing nothing), and have made adjustments to my approach along the way. I have also adjusted based on different varieties and tomato types. The following is a general picture of how I do things to date.
To begin, I do not prune dwarf or determinate (bushing) varieties unless they are showing signs of disease. The following only applies to indeterminate (vining) varieties. That said, wild currant varieties are an exception to the rule. I try to keep them trained as best I can early in the season, but there is always a point where their growth is so fast and furious that I just let them be and try to keep them staked to the best of my ability. I find that they tend to be more disease resistant than many other types.
How I Prune
Early in the season, when the plants are establishing themselves outdoors and producing lots of leaves, I remove all of the lower leaves to establish one main stem, tying that stem up a stake as it grows. I also remove all “suckers” (new stems that come up in the elbow between branches). Of course, sometimes I am not diligent enough or miss a stem or sucker and the next thing you know I have a new stem with fruit. I’m not a perfectionist and find that it’s not a big deal when this happens. It just makes it a little bit harder to stake using my tripod system.
I underplant with lettuce (early in the season) as well as basil and other companion herbs and edible flowers. They attract pollinators, make good use of the space (more food!), and serve to protect the soil from hot sun as the summer heats up.
Later in the season, once fruiting has begun, I tend to stop removing the lower leaves and eventually even the suckers. I used to be diligent about removing all suckers as conventional wisdom held that suckers will reduce the amount of fruit gleaned. Over the years I have loosened up and have found that allowing suckers to develop higher up on the plant has not had a negative impact on my harvest. Allowing them to get out of hand does however, create a mass of unruly stems and leaves that is difficult to train and which can lead to disease (more on that below).
Throughout the season, I remove excess foliage wherever air flow is poor or where signs of disease occur. My goal is to leave enough foliage to feed the plants and act as a sun canopy that protects the fruit from sun scald, while ensuring that air is able to circulate through the leaves easily.
As the season draws closer to the first frost date, I chop off the highest stems in order to direct the plant’s remaining energy into producing ripe fruit. What this means is that I remove any flowering stems that I know will not make it to maturity before the frosts come and kill the whole thing dead. This is a good way to glean more ripe fruit as the plant is not working to produce tiny, immature green things that aren’t developed enough to preserve or eat.
Why I Prune
To Provide Good Air Flow: This is the number reason why I both prune and stake. The two go hand in hand. Toronto summers can be very hot and humid. I have found over time that plants that are allowed to sprawl willy nilly become infected with fungal diseases more easily and even those that are staked but not pruned will also show signs of disease around midsummer when humidity is highest. Removing the bottom leaves ensures that there is good air flow underneath the plant and helps avoid backsplash that can occur when watering. It also makes it easier for me to direct water flow and see exactly what is going on with the soil.
To Protect the Fruit: I have allowed plants to sprawl on the ground, but I find that this leads to a loss of fruit to critters such as slugs, earwigs, and the like. Slugs will crawl up the plant to get to the fruit, but why make it easy for them?
To Make Better Use of Space: As I mentioned above, pruning the bottom growth provides ample space to grow my favourite herb crops. Interplanting in this way ensures that I get a lot of food out of a small raised bed.
Aesthetics: Trained and pruned tomatoes with beautiful, colourful herbs and edible flowers growing underneath simply looks nicer. Neat and tidy but still wild. Enough said.