Jul 15, 2008 - GrowOrganic
I planted some heirloom tomato seed varieties that I bought from you this spring in a bed in which I had plant the Soil Builder mix over the winter season. The soil is rich and has good drainage. I have drip irrigation. The bed gets 4-6 hours of direct sunlight every day, and I live in L.A. so it is warm here.
My tomato plants are 5-6 feet tall, with lots of abundant greenery and flowers. I have only 3 small tomatoes, and the plants have been growing since early May.
Last year I only got a couple of tomatoes too. The soil is nutrient rich, there is plenty of water, sun and heat. What’s the problem???
There are several factors that might be causing your tomatoes to flower but not set fruit. Here are some to consider:
-Too much Nitrogen
-Excessive heat; Daytime temperatures over 90, nighttime temperatures in the mid 70’s
-Less than 6 hours of direct sunlight
-Lack of pollinating insects or wind
Seems to me that your plants are on the edge of the sunlight requirement for good fruit production; 8-10 hours are ideal, anything below 6 is questionable. In case it’s a pollination problem, you might try shaking the flowers to release the pollen.
Hope that helps! Thank you for growing organically!
Jul 15th, 2008 at 10:59 pm
Sounds like too good of soil (high in nitrogen) to me!
Jul 16th, 2008 at 6:48 am
Good information about tomatoes. I have been having similar problems with the heat and my tomato crop since we live in south Georgia. My question is will the plants produce fruit later when it starts to cool down out of the 90’s?
Anthony Milch Says:
Aug 18th, 2008 at 3:24 pm
So the question arises: How does one grow tomatoes when the daytime temperatures are over 90?
I’m in Burbank CA which is in the San Fernando Valley right next to LA and the summer daytime temperatures are typically over 90. This year the entire month of July was well over 90 every day. Last year one day in July was 113.
Fran Ransley Says:
Sep 10th, 2008 at 10:41 pm
It has been a stellar year for tomatoes here in Lake County CA. We are inland and have very hot summer days typically in the 90’s or 100’s and cool nights into the 70’s or even 60’s. This spring was very cold. For the first time ever I used black plastic mulch and it helped tremendously to warm the soil and get the tomatoes and squash off to a good start.
I have never had a problem with tomatoes not setting fruit during hot weather. Perhaps it’s the varieties that I plant which seem not to mind the hot days.
I’ve got Early Girl (they are over 6’ tall and have everything from ripe to small green fruit). Also Lemon Boy performs well here. I’ve got a gold cherry tomato Sunburst I think which has been very prolific but seems to have peaked. And Celebrity which does well but the fruit cracks sometimes. Sweet 100 is still producing like mad. I also have a Prudence Purple not as prolific as the others but wonderful flavor and a purple Brandywine. I usually plant Champion but didn’t this year as I wanted to try the purple varieties and my space is limited.
When looking for varieties to plant I choose those resistant to fungal wilts which seem to be in my soil.
Sep 11th, 2008 at 1:54 pm
I went down to talk to Linda our nursery manager.
The basic gist (and I will post this on the blog as well) that for the most part high temperatures are not a problem in fact tomatoes can love it but according to our nursery manager there are two things that can happen: one if there is not enough foliage the leaves can get burnt and the fruits will not develop out of the blossom.
One solution for this dilemma is to get a specific grade shade fabric or even to use Agribon as shade cloth.
Two: ““early”” varieties are not the way to go if you live in a hot spot. Varieties that take perhaps longer to develop and are used to end of season high temperatures are more likely to do well in sweltering heat. So basically you want to compare germination periods of the seedlings or seeds you end up buying and if you live in a real hot place go for the longer germination periods.
To tell you the truth this was good for me to learn as well. I’ve already realized after looking into this that a common mistake is to simply over fertilize the soil… for me that can be a problem since I grow in containers. Another trick that I have neglected to employ is to prune or pinch off the leaves that come out of the ‘elbows’ of your plants’ limbs as they will not produce fruit and take energy from the rest of the plant.”
Sep 15th, 2008 at 9:18 am
“Daytime temperatures over 90 and nighttime temperatures over 70 can cause poor flowering and fruit set. To remedy shade fabric can be used during the day to block some of that sun and heat. 30% fabric (SES090) is sufficient for tomatoes.”