Vegetable garden – where are the pollinators?

(Question)

I’ve got a variety of edibles, tomatoes, zucchini, cucumbers and beans, all but some of the tomatoes in containers. They get enough sun, have good leaf growth so far. I am not seeing a lot of fruit, e.g. brandywine tomatoes haven’t had a single fruit set but several dead looking flowers. I also haven’t seen a single butterfly this summer, and only two bees. Has it been common this June to lack pollinators? I went out and bought some (expensive!) flowers to help (sunflower, escheria, marigold), but I’m welcome to hear other suggestions.

 

(Answer)

I’ve not seem many pollinators so far this spring/summer, either – although a number of bees visited my garden, and a few butterflies.  The flowers you planted to attract pollinators should look lovely in your garden, but may take some time to establish and “do their job”. Additional plants that may be of interest to you, as well as other strategies to attract pollinators are set out in Pollinator Garden: A Toronto Master Gardeners Guide.

Brandywine tomatoes are not known to produce a lot of tomatoes, and heirlooms like this one may take longer to start setting fruit than you might see with hybrid tomatoes.

Remember, too, that some tomato varieties are not expected to have set flowers yet.  Some varieties are “determinate” – these grow like bushes, up to 3-4 feet high.  Once they reach full height, then start setting flowers all at once — then the entire tomato crop will ripen within a couple of weeks.  “Indeterminate” tomatoes (like your Brandywine) tend to sprawl and need to be staked/supported.  They set flowers throughout the growing season — sometimes only a few flowers at a time — and tomatoes will keep ripening over a much longer period than you see with determinate varieties.  See NC State University’s Consider Pruning your Tomato Plants to get more Fruit Production.  This also discusses “pinching” and removing suckers that sprout in the crotch joints between two branches in indeterminate tomato varieties — these never bear fruit and although they make the plant look leafier, they divert the plant’s energy away from making fruit.  On the other hand, pruning suckers of determinate tomato varieties may not be such a good thing, and could decrease the fruit yield.

We can’t control the odd, wet summer season we are having in 2017, with all its temperature fluctuations.  However, it is important to make sure that all the conditions that we can control that promote good growth of vegetables, are in place — this includes ensuring that the plants receive full sun, are in well-draining soil with lots of compost and mulch to help retain moisture, and are watered regularly (they should never dry out).  Tomatoes are fussy and there are a number of conditions they don’t like, including:

  • temperature extremes
  • high humidity (this interferes with pollen release and the ability of the pollen to “stick”)
  • too much or too little nitrogen fertilizer
  • lack of water. The plants have deep roots and shallow watering stresses and weakens them. Keep the root zone consistently moist through the growing season

For more information, see Missouri Botanical Garden’s Tomato Fruit Problems.

As well, Washington State University’s Why blossoms of some vegetables fail to set fruit  discusses how you can help pollinate the plants – gently shake the entire plant on a warm day, around noon, when humidity is relatively low. Or you can hand-pollinate the plants using a Q-tip or small brush.    The University of Florida Extension’s The Birds & the Bees – Pollination in the Garden  provides further details on hand-pollinating.

All the best with your veggies!