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Why Are the Flowers Falling Off My Tomato Plants

We regularly receive gardening questions here and we always do our best to answer your questions personally, or to point you to an article that will be of value to you. Here is a question, one that plagues many gardeners, from Darlene.

 

Question: Why are the flowers falling off my tomato plants? My tomato plant grew to over 5 feet high, and produced many flowers, not one single flower turned into ANY type of tomato. I was extremely disappointed as this is the one vegetable I love to eat fresh.

They did not lack water as I made sure they were always maintained. I also gave them Miracle-Gro tomato fertilizer and bought a special dirt to plant them in when I received them. As I mentioned, this is the one thing I look forward to every year. I look forward to your response to learn why I never got any tomato. As soon as the flower would fall off, normally this is when the tomato begins growing, nothing came.

I appreciate your time and help.

Thanks, Darlene

 

 

Answer:

Darlene, We are very sorry that you did not get to enjoy lots of great, juicy tomatoes this year!

Without having personally witnessed your season, we’ll take a stab at this. This is most likely a condition called blossom drop. You can learn more about it and other common tomato problems here. The flowers of tomato plants are actually pretty picky about temperature and pollination and it varies from variety to variety.

Generally, blossoms may not develop or pollinate if daytime temperatures exceed 92°F and nighttime temps are above 68°F. Temperatures falling below 55°F in the evening can also inhibit pollination. This is one reason it is important to not set your tomato plants out too early. It seems the heirloom or older varieties are more sensitive to temperature extremes.

If you’ve had an extended period of extra warm days, it will aggravate the situation, as will hot, dry wind and low humidity. Dry soil can also cause poor fruit-set, so make sure that you mulch the plants and water deeply at the base of the plant, once or twice a week.

Another factor may be too much shade. Make sure your tomato plants are receiving at least six hours of full sun daily and not being overshadowed by other vegetation or trees that may cast their shadows upon your tomatoes.

You mentioned your tomato plants were quite vigorous growers and that you added a “special” soil and fertilized them often. Even though Miracle-Gro® Tomato Plant Food is supposed to be balanced for your tomato plants, it has an NPK of 18-18-21, meaning it has a high nitrogen and high phosphorous content, with even higher potassium. The nitrogen makes the plant grow lots of leaves, the phosphorous is for blooms, and the potassium is for root development and photosynthesis. Additionally, I am guessing the soil you purchased was a compost or manure mixture which will also supply lots of nitrogen to your plants. It’s very possible you may have thwarted bloom development by trying to be nice to the plants, inadvertently providing them with too much nitrogen. Nitrogen will cause fantastic growth and leafing; too much nitrogen can mean that the blooms may fall off prior to setting fruit.

Here are some tips that may help: (1) Add your compost to your soil this fall; mix it in and let it sit over the winter. (2) Next spring add a small amount of Espoma Plant-tone® 5-3-3 to the garden bed when you prepare it for planting. (3) Add some organic mulch around the plants and then water as needed when nature doesn’t provide enough moisture. (4) Fertilize sparingly with a higher phosphorous fertilizer to encourage blooming, only adding nitrogen if your plants are looking a little pale or yellowish or are not growing well.

If the temperatures are above average, definitely restrain your use of chemical fertilizers, maybe switching to a milder organic variety. The hot weather will cause the tomato plants to be under stress, causing the roots to not be able to absorb and distribute the nutrients properly, also causing flowers to fall off of your tomato plants.

We hope this helps and we wish you better luck next summer. If you’re looking for new, interesting, and/or heirloom tomato varieties, check out our selection. We’ve handpicked and organically grown only the best varieties for every garden situation.

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