In November last year I started the first of the tomato trials for the season. This one set out to compare the difference between pruning to 1 or 2 stems on the yield of fruit.
Each bed was planted with 4 varieties; Amana Orange, Pineapple, Black Cherry, Yellow Tommy Toe.
In addition, basil, cosmos and marigold were planted.
Early in the season the weather was quite humid resulting in more fungal issues that would normally be seen in our climate. This likley had some impact on the result but given the trial is subjective in nature since no actual yield measurmenets are taken, I’m confident any differences are vaild.
Whilst it seems obvious now, I think it’s worth pointing out that by pruning to a single stem, you greatly limit the amount of fruit that can grow in a single plant. The flowers on a tomato plant are directly off the main stem, not the leaf, and you see alternating leaf/flower spike/leaf/flower spike as you go up the stem. This then begs the questions, why would you bother if you get less fruit? A heavily pruned plant takes up much less space, has less leaf mass and therefore, greater air movement around the plant which in turn, should reduce fungal issues. You can plant much closer together which makes up for the reduced yield per plant.
As expected, the single stem plants produced significantly less fruit per plant for all 4 varieties. The fruit, however, was much larger with some fruit the size of a golf ball. Conversely, the plants pruned to 2 stems produced a lot more fruit but were smaller, much more like a good sized cherry tomato.
I’ve continued to use the single stem method for tomato plants now growing in the greenhouse but in the future, I’ll prune to 2 or 3 stems in the vegie patch.