Ask the gardening expert
Thursday, September 1, 2011
I know I am supposed to prune some leaves from my tomatoes to let the sun on to the plant, but I don’t remember which leaves or when they need pruning. Can you tell me?
There is a common belief that pruning leaves from tomato vines will allow sun to get to the fruit and ripen it faster.
Research proves that just the opposite is true. The leaves produce sugars and other things that are transported to the fruit to make them grow and ripen. Direct sunlight is not required and, in fact, it can cause sunscald on the fruit.
However there are occasions when you should remove some leaves from the plant. If you are training the vines up a trellis, net or stakes, cut out some of the suckers — or secondary branches — that start between leaves and stems. This opens the plant up and provides better air circulation, which helps to prevent late blight. Pruning lower leaves of staked plants, ones touching the ground can also help.
The only other pruning recommended is nipping off flowers and pea-size fruit later this fall. These don’t have a chance anyway, so you want to direct the plant’s energy to ripening the bigger green fruits before frost. Another late summer gardening reminder is to keep beans, cukes and summer squash picked or the flowering and fruiting will slow down. If you have more than you can use, remember the local food bank can use your bumper crop.
Celeste Lindsay is a WSU-master gardener. Send questions to firstname.lastname@example.org.