My tomato fruits are pretty big at the bottom, but they become smaller and smaller on the upper parts of the plants.
I would like to know why and how to grow bigger fruits.
Also How many fruits/cluster should be kept on the plants. When should I snip the top of the plants off ?
I’m sorry to hear that your tomato plants are now producing smaller fruits.
There are several possible causes:
- Not enough sunlight
Tomatoes are full sun plants and need a minimum of 6 hours of direct sunlight to thrive. Is there something casting shade on your plants?
- Lack of water / drought
Consistent watering is essential. Did the plants dry out when they were setting fruit? Tomato plants should never be allowed to wilt. Deep watering will encourage your plants to develop a robust root system. An application of compost as mulch will help retain moisture and insulate against heat.
- Stressed plants / Temperature & humidity
Flowers and fruit may not fully develop on stressed plants. Were the plants in flower during a heatwave? Cool nights can also affect fruit set. Are there any signs of insect pests or disease?
- Excess fertilizer
Nitrogen rich fertilizer promotes leafy foliage and can inhibit fruit production.
- Poor pollination / lack of pollinators
Extreme humidity can inhibit pollination. Cut open a fruit to see how many seeds have formed. Most tomato plants are self-pollinating, and you can help them out by giving the plants a gentle shake. Grow some native flowering plants to attract pollinators. Avoid using pesticides and ask your neighbors to do the same.
Here is a link to a Toronto Master Gardener answer that provides further information on the pruning and care of tomatoes:
July 27, 2021