Expert: Mike Mascio - 10/19/2009

Question
It seems just when the plant is full with blossoms and looking awesome, it starts to drop its blossoms.  It is happening now. Is this normal this time of year? I am in Southern California and I've seen others in my neighborhood and the seem to stay full all year long?  What am I missing?

Answer
When blossoms fall off prematurely, it is usually an indication of one of two problems. Either your plants are not being fully pollinated, or they are receiving too much water.

If you do not have enough bees in the area, you can hand-pollinate the flowers of most plants by taking a Q-tip or small paint brush and transferring the pollen from the male flower to the female (the female always has a small fruit on the end). This must be done within one day of the female flower blossoming. To attract more bees, grow sunflowers, marigolds, cosmos, or some other bright annual in the immediate area.

One other possibility is that you are over-fertilizing the plants. Many of today’s water soluble fertilizers are very high in nitrogen. This results in lush foliage but often at the expense of a smaller harvest. Look for a fertilizer higher in phosphorus and potassium. Many companies now market products formulated especially for tomatoes.

In summary, remember to continue fertilizing with a low nitrogen fertilizer once every other week, and only supplement enough water to ensure a depth of 1.5” per week. Water only once or twice per week but very deeply. Shallow watering always results in poor root development and smaller harvests. Also, be sure to mulch heavily with straw or dried grass clippings around the plants to retain moisture, cool the soil, and to reduce the need for watering.

Good luck, and please write again if I can ever provide assistance.

Regards,

Mike