Tomatoes Not Setting Fruits

“I purchased Tomato Plants and I am so disappointed. While the plants seem healthy we only have 3 tomatoes (the size of a golf ball) 2 on one plant and one on the other. It is now Aug 24th and we haven’t had 1 tomatoe yet. We have lots of flowers. What is the problem. ~N.”


Thank you for your email regarding your Goliath Tomatoes.  If your plants look healthy, temps are not too hot, and the breeze is blowing your flowers will self-pollinate soon enough and you will start to see some fruit setting. Be patient. I know, I know it can be so hard to be patient.

It is never a bad idea to gently shake the plants to help the flowers self-pollinate. Some people use an electric toothbrush at the base of the bloom.

Also, there may be a bit of a nutrient imbalance in your soil that is preventing fruit set.  Commercial fertilizers list three very important numbers on the package

. This is what is referred to as the N-P-K ratio. The first number always represents the percent of Nitrogen (N). The second number is percent Phosphorous (P). The third number is percent Potassium (K).

(N) Nitrogen stimulates the growth of the green stuff, i.e. leaf growth and general plant growth.  You do not want to use too much nitrogen, as it will prevent blossom set.

(P) Phosphorous stimulates the root growth, flowering and fruit set.

(K) Potassium stimulates fruit production.

Since you do have blooms I think all is probably proceeding as it should. But if you want to give your plants a quick boost in fruit set and production I might suggest a very diluted foliar spray of something with a higher P and K value relative to N value. Plants have the unique ability to take in nutrients through their leaves. It is important to choose a time of day when temps are lowest to spray the leafs. The cells on the leaf (stomates) that can accept a foliar spray are only open when temps are below 72 degrees. Most stomate cells are located on the underside of the leaf.




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4 thoughts on “Tomatoes Not Setting Fruits

  1. That sounds typical for nighttime temperatures above 20 deg. C (68 deg. F). Daytime temperatures do not matter. Under high nighttime temperatures, the pollen gets infertile and/or pollination does not occur. Wait until it cools off at night!

    • Volker, you are partially correct. Warm tempertures at night have been shown to affect pollen grain formation and pollination at night if temperatures remain above 85F. However, research from UC-Davis has found that a more common cause of the problem are temperature over 90 degrees F during the day or below 55 degrees during the day or night. Both of these take the plant out of the optimum range for various enzymes to work properly, thus resulting in abnormal pollen that is essentially sterile or no pollen at all.

  2. Great read! But, I had a difficult time viewing this article in Internet Explorer 8. Just wanted to bring that to your attention! Best regards.

    • Hi Albert,

      I’ve had problems with the content when I have ran Internet Explorer. I recommend using Firefox or Chrome — both are more integrated with the content of WordPress. Best Wishes!

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