August 31, 2014

Q&A "Tomato Sex"

I just rediscovered a series of Q&A my friend and I did on the "I Love My Farmer! (Local Farmer Fan Club)" Facebook group I created years ago when I was operating an organic microfarm. I thought some of you might find them useful:

"Tomato Sex"

Dear Local Farmer,
My tomatoes are blooming big time, but no tomatoes! Same goes for by beans, cucs, and squash. I put out sugar water to attract bees, but no luck. I tried brushing my fingers lightly on the an attempt to help them get it on.....any advice????

---Low-libido tomatoes in Austin

my response:
Dear Low-libido tomatoes,

While bees will appreciate your sugar water when they find it, there may just not be any bees near enough to your garden. Bees will only fly a certain distance from their hive to forage for food.

However, beans and tomatoes have "perfect flowers" (the flower contains both a stamen and pistil) and so self pollinate. You should be getting fruit in spite of your lack of pollinators. Good idea to brush the flowers although you don't have to try an transfer pollen between them when you do. Suzanne Ashworth in Seed to Seed says that tomatoes "will set more fruit if the flowers are agitated...this increases the amount of pollen traveling down the anther tube...daily shaking can be used to increase flower set in caged tomatoes." I met a guy who told me his grandmother went out each day and beat the crap out of her tomatoes with her cane claiming she got more fruit that way...maybe there is something to it. Other things could be at issue though.

Lets look closer: How long have the flowers been blooming? Have they had time to begin growing the fruit? Are you seeing dead flowers followed by no fruit or are the flowers still all fresh? What are your night time temperatures? Tomatoes have a hard time setting fruit if the air temperature doesn't fall below 75 deg for a number of nights. It's not impossible, but they will become distinctly less fertile. Tomatoes also need 8-10 hours of direct sunlight. Less can cause poor fruit set, although with all those flowers, they are probably getting enough light. Also, you might try spraying the plants with a solution of epsom salts... 1 tbl salts in 1 gallon of water. I'm not sure if your soils are magnesium deficient (or if the magnesium, while abundant, is inaccessible) but since that nutrient is so important to the formation of fruit, people often find epsom salts instigate fruit set.

As for the beans, how long have they been blooming? I find that fruit set on beans just takes longer than I think it does. It will seem like the plants have been blooming for a month before i see beans. Also, there are often tiny beans growing that I just don't notice for a few weeks until they're bigger so it seems like they're not setting. Look closely. Other than that, are the plants themselves looking healthy? No stunting or chlorosis (yellowing in the leaves)? If all looks well, I would say wait a bit longer and see what happens.

Cucs and squash: These guys do need insect pollinators and so the lack of bees could be an issue. They can be pollinated by hand (although it might be a pain in the case of the cucumbers since they develop so many blooms and the blooms are so small). First you need to identify the male and female flowers. The female flowers are sitting atop the ovary which is (and looks like) tiny immature fruit. The male flowers are sitting on a straight stem. In the morning, after the dew has dried, pick the male flower with the stem attached. Strip the petals and holding the stamen by the stem end rub the pollen on the stigma of the female flower. Apparently pollination is more successful if several male flowers are used to pollinate each female flower. With the cuc flowers, since they are so small, it may be easier to use a very soft bristled tiny paint brush to transfer pollen. I would try gently inserting it into male flowers and then inserting it into female flowers and see what happens.

I hope this helps!

---Local Farmer

and her follow up:

Thank you, Local Farmer!
Ah-ha! I shook them up and now have a plethora of baby tomatoes!

---Low libido tomatoes in Austin