Pruning tomato plants is an optional technique that some gardeners use to keep plants tidy, manipulate fruit size, and even speed ripening. There is one big catch: You should only prune indeterminate varieties, which produce new leaves and flowers continuously through the growing season.
Pruning tomato plants: top them When the tomato plants have grown as tall as the support pins, I top the plants. That is, if they get that far before summer turns to fall. The point of pruning tomato plants is to make sure that they spend more energy on ripening the fruits instead of rushing to grow taller.
Most grow to three or four feet tall, although some patio varieties top out at 12 inches. Indeterminate tomato plants, which tend to vine, require trellising or cages, continue to grow, and produce fruit until the first frost.
You only need to worry about pruning if you're growing a vining type, aka an indeterminate tomato. Bush tomatoes, or determinate tomatoes, are basically self-pruning because they're meant to only grow to a certain size and then stop.
You prune a tomato plant by pinching off the suckers that emerge from the crotch of limbs. Imagine that there are two branches coming off your plant. Then a third one emerges between them. That third one needs to be eliminated. You can do this by pinching them, although sometimes that doesn't deliver a clean break.
Do all tomatoes have to be pinched out? The simple answer is no. With large-fruited tomato varieties such as ox-heart and beef tomatoes, however, the side shoots should be removed. Even with medium-sized indeterminate tomatoes, we recommend only leaving a maximum of two to three shoots, including the main shoot.
It is ideal to clip within a few inches of every fruit cluster. If this puts your clips close together it is alright, more is better in this situation. As long as you keep your leader vine well supported and ensure the plant has enough leaves up top to provide canopy, your vines will continue to produce fruit.
Remove "suckers" (small shoots growing in the leaf axils between the main stem and branches). Trim off lower leaves that touch the ground to prevent soil-borne diseases.
Beefsteaks thrive most if planted deeper in the ground rather than being planted in containers. As the plant grows, you should prune it regularly. As side branches form on the main stem, pinch out "suckers" or new growth when they are young and only 1/2 inch long that form in the crotch of the stronger branches.
The primary culprit behind tall and spindly tomato seedlings is insufficient light exposure. When tomato plants don't receive enough light, they stretch upward in search of more, resulting in elongated stems and a weak structure.
Generally, animal dung from non-industrial farms is the most popular organic fertilizer used in tomato cultivation — cow, horse, and sheep-goat manures work best.
Most modern determinate tomatoes easily grow 3 to 4 feet tall and indeterminates continue to get taller until frozen in the fall, easily reaching at least 6 feet in height.
To speed ripening late in the season, remove the growing tip of each main stem about four weeks before the first expected fall frost. Called "topping," this type of pruning causes the plant to stop flowering and setting new fruit, and instead directs all sugars to the remaining fruit.
Too much water or too little water can cause leaves to turn yellow. What to do: Avoid overwatering your tomato plant by checking the soil moisture before turning on the hose. Sink your finger into the soil at the base of the plant.
The most common cause for small tomatoes is stressed plants. When plants are experiencing stressing circumstances, such as extreme drought or heat, insect infestation, or disease, they oftentimes stop sending their energy into flower or fruit production.
Water correctly: Do not overwater. The first week tomato plants are in the ground, they need water every day, but back off watering after the first week, slowly weaning the plants down to 1 to 1.5 inches of water per week.
This means pinching out the growing tips at the top of the plant and stop the plant growing up any further. Stop off at the top of the plant when there are 3-4 (outside grown) and 4-5 (greenhouse grown) trusses, which are layers of flowers.