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written by
Marianne C. Ophardt
WSU Extension Faculty
for the Tri-City Herald, Kennewick, WA
published- JUNE 27, 2014


Cucurbits (squash, cukes, and melons) are popular garden veggies. That is probably why questions about cucurbits are second only to tomatoes when it comes to problems that gardeners encounter in their vegetable gardens.

A common question is, ‘why aren’t I getting any squash even though my plants have a lot of flowers?’ To understand the answer it is important to know that cucurbits have separate male and female flowers. Only the female flowers can produce fruit and only the males produce the pollen needed for pollination and fruit development. The cucurbits depend primarily on honeybees to transfer the pollen from the male flowers to the females.

In order for pollination to occur, both male and female flowers must be open at the same time. Typically, cucurbits produce all male flowers at the start of flowering and a little later also produce female flowers. Conversely, plants of hybrid cucurbits generally produce female flowers first and male flowers second. However, before long both sexes of flowers are open at the same time and then the bees must go to work.

Once male and female flowers are blooming at the same time, there are several reasons that fruit still may not develop. Lack of honeybees or low bee activity due to hot weather, wind, or rain can hamper successful pollination.

If the honeybee population is low or nonexistent, you can assume the duties of a honeybee. Do this by picking a freshly open male flower (they have pollen in the center) and removing the petals, leaving the center portion (anthers) with the pollen. Insert this into the center of a newly open female flower (has a baby fruit at its base). Gently move the anthers around to transfer the pollen from the anthers to the center structure (stigma) in the female flower.

Another common cucurbit question comes from area gardeners when they discover small to large dry whitish or tan spots on the leaves of squash, melons, or cukes. It is typically most severe on the plant’s larger, older leaves and not evident on the youngest leaves. It looks like a disease problem, but it usually is wind injury. This occurs when the winds buffets the leaves about, causing the spiny surfaces of the leaves and stems to wound themselves. Badly injured leaves will be very brittle and often tear after additional windy weather. Placing a garden in a less exposed spot or shielding the plants from wind in some way might help.

Area gardeners also wonder why the leaves of squash wilt during the day and then perk back up in the evening. Is it a wilt disease or squash bugs? No, this daytime wilting indicates that the leaves are not being supplied with enough water to keep up with the amount of water they are losing through their leaves during the heat of the day. This ‘lack’ of water may be caused by too little soil moisture, a poorly developed root system, root rot from too much water or poor drainage, or root damage from enthusiastic weed cultivation. Consider the situation and try to remedy it for a healthier, more productive plant that does not wilt during the day.

Other common problems to look for on cucurbits are squash bugs and powdery mildew. You can find out more about these on the WSU website called ‘Hortsense,’ short for Horticultural Sense. You can find Hortsense at Start looking for squash bugs now.

Published: 6/27/2014 11:40 AM


written by

Marianne C. Ophardt

WSU Extension Faculty

for the Tri-City Herald, Kennewick, WA

Knowing when and how to harvest members of the “cucurbit” family can be a bit tricky. This garden veggie family includes watermelons, cantaloups, pumpkins and winter squash.

Gardeners can use a combination of indicators to tell when their watermelons are ripe for the pickin’. It’s important to harvest watermelons only when they’re fully ripe, because they don’t get any sweeter after picking. The first sign of maturity is the curly vine tendrils close to a particular fruit turning from light green to dry and brown. As the fruit matures its skin becomes rougher and harder to pierce with a fingernail.

While some gardeners still insist on thumping their watermelons and listening for a hollow sound, the color of the bottom spot where the melon touches the soil is more reliable. As the fruit ripens, the bottom spot changes from greenish white to a buttery yellow or creamy white.

The ripeness of muskmelons and cantaloupes with netted skins is a little easier to determine. These melons are ready for harvest when they “slip” or are easily pulled off the vine. Other indicators include feel, color, and aroma. The netting becomes rougher and the skin between the netting changes from green to yellow, golden orange, or tan. The flower end of the fruit (the end opposite of the stem end) will be slightly soft. Finally, a good sniff of a ripe melon will reveal its tantalizing aroma. Like watermelons, cantaloupes don’t increase in sweetness after picking, but will soften a bit and develop better flavor if held at 70 degrees for several days.

There is no trick involved in telling when a pumpkin is ripe. When its skin turns hard and uniformly orange (except for some specialty varieties), it’s ready. It’s important to harvest pumpkins before a hard frost because the freezing temperatures can damage the skin and lead to rot in storage, although they usually can tolerate a light frost without trouble.

Pumpkins are “picked” by cutting them from the vine, leaving at least a three to six inch portion of stem attached to the fruit. Handle carefully to avoid scratching and bruising. Do not carry them by the stem. Wash off dirt with clean water and then “cure” the pumpkins. (Some gardeners like to wipe them with a ten per cent bleach solution or diluted household disinfectant to help protect against rot before curing them.)

Curing toughens the skin and allows for longer storage. To cure the fruit, place them in a warm (about 80 degrees) location for about a week or two and then store in a cool, dry place. All is not lost if your pumpkins haven’t turned completely orange by the time frost kills the vines. The curing process may encourage mostly green pumpkins (those just starting to develop some orange color) to turn orange.

Pumpkins are easy, but it’s more difficult to tell if the many other types of winter squash are mature and ready for harvest, especially if you’re not familiar with their mature color and size. Refer to the variety description to insure the fruit has reached the typical size and color for that variety. Also, their stems should be hard and the skin difficult to puncture with a fingernail. Like pumpkins, they’re cut from the vine, washed and cured.

Knowing when to harvest the cucurbit family may be a bit tricky, but there’s no trick involved in enjoying what we harvest. Yum!

Published: 8/22/2009 10:43 AM



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