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.
You want to start pruning tomato plants a when they get to be about 1 -- 2 feet (30-60 cm.) tall. Any smaller than this, and the plant may not recover from the shock of being pruned. By the time your tomato plant gets to be this size, the plant will have branches coming off the main stem.
From a plant disease perspective it's not too advisable to top your tomato plants. pulling off flowers and suckers are more advisable because you are not creating large wounds.
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.
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.
Potassium (K)
Potassium is essential for optimal tomato growth and quality. Potassium nitrate is the recommended source because the nitrate form facilitates easy potassium uptake by the plant.
For example, some gardeners “pinch back” suckers on their tomato plants. This means removing the shoots that appear in the “V” or “axil” that is created between the branch and the main stem of tomato plants.
However, tomato plants can be a bit finicky when it comes to getting too close to their tomato neighbors, and they like a bit of space between themselves and their fellow garden companions.
Some gardeners recommend you “pinch off” the flowers on your tomato transplants during their first weeks of growth, claiming that removing early blossoms: Directs more energy into establishing a strong root system. Results in a larger, sturdier, and potentially healthier tomato plant.
Also the lower leaves tend to get powdery mildew so it is good to remove them to stop disease spreading.
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.
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.
Starting in mid-August, blossoms on large-fruited varieties will not mature and ripen before the end of the season. Remove blossoms and small fruit to encourage ripening of the remaining tomatoes. Reduce or stop watering about mid- to late-August to stress the plant and encourage ripening.
Tomato plants have big appetites and need a steady supply of plant food to grow their best. Miracle-Gro® Performance Organic® Edibles Plant Nutrition Granules feeds both your plants and the beneficial microbes in the soil (which help plants take up all the nutrition they need) for up to 6 weeks.
Tomatoes thrive in loamy soils with good drainage and high organic matter content. Adding composted coffee grounds to planting beds is a great way to build healthy soil for tomato planting but won't provide all the required nutrients.
Tomatoes are prone to magnesium deficiency later in the growing season, which can show with yellowing leaves and diminished production. Ultra Epsom Salt treatments at the beginning of their planting and throughout their seasonal life can help to prevent and remedy magnesium deficiency in your tomato plants.
Give them consistent watering (deep and infrequent trumps a daily sprinkle), well-draining soil (incorporate generous helpings of compost into beds or containers at planting time), plenty of heat and light (direct, unobstructed sunshine for a minimum of 6 hours daily is best) and a slow-release, balanced fertilizer ...
Leave the sucker just below the first flower cluster (remove all other suckers below that one), and allow all suckers above the first flower cluster to grow. Indeterminate varieties will reach and exceed the top of the stakes.
That means a conservative estimate for the total number of tomatoes harvested during the season would be over 400 tomatoes, or roughly 100 tomatoes per plant. If you grow tomatoes the way I do, it's safe to bet on getting at least 100 tomatoes off your plants within four to five weeks during your peak season.
Topping tomato plants is only beneficial for indeterminate varieties and isn't necessary for good health or high production.
Remove all leafy suckers beneath the first fruit cluster so they won't slow the development of the fruit. Suckers are the little shoots that form in the spot (called an axil) where the leaf stem attaches to the main growing stem. In northern regions, many gardeners go further, removing all suckers as they appear.
Don't pick too many leaves from a plant at one time.It scares the plant and it does not like that. Far better is to prune 2 to 3 leaves regularly (like once a week).