Watch any plant of the cucurbit family in summer (cucumber, squash, melons) and you’ll see a lively drama unfold. Bright yellow flowers open in the morning to receive bees, eager to burrow deep within for nectar and pollen. In so doing, they transfer pollen from the male stamens to the female stigma — a little golden circlet that crowns the ovary, where a new fruit will form. Members of this tribe have both male and female blossoms on the same plant, and if all goes well the ovaries of the female will soon swell and turn into something that resembles a tiny cucumber, melon or squash. If you see a lot of bees going in and out of the flowers, it’s a good sign.
It’s also a good sign when the little fruits start to appear, but it does not guarantee success. Fruit set can begin without pollination and — unlike a human woman — a female squash blossom can be a little bit pregnant if enough pollen has landed on the stigma to get the fruit going but not enough to create a vegetable worth picking. That takes numerous bee visits. For instance, you might have seen a little zucchini get off to a good start, then turn to mush at the flower end. That’s not a case of blossom end rot; it’s a poorly pollinated fruit that can go no further. If you get a small harvest of cucumbers or melons, inadequate pollination might be the cause there as well.
So along with giving your plants good soil and sowing them on time, you need to think about bees. If, for example, you covered your early cukes with row covers to prevent early damage by cucumber beetles, or covered your squash against squash beetles, you must remove those covers as soon as blossoms start to appear.
It’s also worth keeping track of bee numbers. Are there lots of them on each plant or just a few? If you’ve planted cucurbits inside a greenhouse to get an earlier harvest, are the bees coming inside? (Growers sometimes place bumblebee hives inside greenhouses because they will work under glass or plastic, while honeybees will not.)
If you see a lack of bees outdoors, think about what you could plant to attract more of them. Even if there are few honeybees around, many species of native bee will be lured to a yard full of nectar-rich flowers. Observe which flowering plants bloom at the same time that cucurbits are flowering, and watch to see which ones are quivering with active bees. Those that bloom in the purple range are their favorites, and it takes only a glance to see that catmint, followed by any of the purple-flowered sages, is bee heaven. From there, move on to liatris and bee balm in midsummer and purple asters for fall. Hate the color purple? Get over it.
And don’t use poisons in the garden. The number of articles tracing huge bee die-offs to chemical pesticides such as the neonicontinoids (see www.xerces.org) is not only a sad tale of furry little bodies lying dead. It could also foretell poor harvests for you.
Damrosch's latest book is “The Four Season Farm Gardener’s Cookbook.”