Sow There!: Summer zucchini and how to help green food survive the heat June 23, 2017

Only two zucchinis have grown to full size, and this heat wave might mean that's all for the season.
Only two zucchinis have grown to full size, and this heat wave might mean that’s all for the season.Photo by Heather Hacking

The past several years zucchini season has been something to celebrate. If we’re going to have blistering hot weather, at least there’s a green reward when you drag the hose to the raised bed.

I thought it wasn’t going to happen for me this year. My sister and I will be trekking through Costa Rica in July, and most of the early zucchini shriveled after reaching only the size of my finger.

The more I researched, the more I realized my squash problem could be one of many things: Lack of good pollination, not enough water in the raised bed, lime deficiency, bad luck.

I pollinated by hand, soaked the raised bed and added lime, so now I’ll never know what helped two zucchinis grow to full size.

The lime, by the way, was ill-timed. The only reason I bought the bag of lime was that it was really hot and I found myself wandering slowly through the garden section of a big-box store. I’m a big fan of using other people’s air-conditioning when it’s 109 degrees.

I bought a bag of lime packaged for hydrangeas. The plant-food marketers noted that the granules are helpful for turning hydrangea flowers pink. It wasn’t until after I added heaping spoonfuls of lime to the soil in my raised bed that I learned it can take months for lime to be useful to plants, and I should have added the stuff in the fall.

As with most things having to do with garden chemistry, it’s best to have the soil tested so you’re not spending $4 on another bag of junk that will sit in the shed until 2029.

Send me a note if you have had your soil tested. I’ll write about that before 2029.


Last year the zucchini harvest was fast and furious. I ate one elongated, green fruit each day for at least two weeks and even had a few extras to dump on the neighbor’s front door.

However, after this heat wave, I’m less hopeful. Human motivation slows to a crawl when walking outside feels like being zapped by a heat death-ray. Plants react similarly.

A rather scholarly article from the University of Delaware,, describes how plants make it through the heat through transpiration. Water vapor is released from pores at on the underside of the leaves and makes life just a little more bearable or the plant. If the plant runs out of water, this process stops. The best thing we can do is mulch, mulch, mulch. The problem is, humans are inside by the air conditioning at exactly the same time our plants need us most.

Other tricks for hot-weather include providing temporary shade, especially to block out the afternoon sun from the west.

Rather than lament more hot weather problems, I’m going to be grateful that I received the gift of two beautiful zucchinis before heading to near the equator. If that’s all that arrive, I know there are more than a few farmers markets in town, and I trust those growers to shade, mulch and water with more know-how than I possess.


While we’re waiting indoors to see how well our plants survive, we might as well remember why zucchini are such an awesome food. The SELF Nutrition Data website,, notes that one cup of zucchini contains 40 percent of daily Vitamin A needs and 9 percent of that elusive Vitamin K. If you’re looking for magnesium, manganese or potassium, this fruit has your numbers. Also, with under 30 calories per cup, you can fill up on zucchini for lunch and have a grumbling stomach by midafternoon. By the time you head to Shubert’s for a well-deserved summer treat, you won’t feel any guilt for the warm-weather indulgence.

Garden enthusiast Heather Hacking can be contacted at Many of her archived articles, some of them informative, can be found here:

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