Tornadoman

You will be happy to learn that what you were told about melon types crossing is erroneous. The old garden folklore that 'you should never plant cucumbers next to squash or melons because they will cross-pollinate and produce off-tasting fruit" has SOME basis in reality, but only for members of the squash family. And, even then, the effects of the cross-pollinated squash will not be seen in this year's fruit or plants. If, however, you save seed from one of this year's cross-pollinated squash and plant that seed next year, then it might produce odd fruit resulting from the cross-pollination.

The myth that plants from the cucurbit family will cross with one another is an old one, and it probably continues to make the rounds because it seems logical and believable. Even though the cucurbits are related, they are from different branches of the same family and don't cross-pollinate.

First, though, you need to understand how the cucurbits reproduce, as they are unique among vegetables. Cucurbits are 'monoecious' which means each plant has both male and female flowers. The female flowers have tiny immature fruits at the base of the flowers. The male flowers don't. For fruit set to occur, pollen must be transferred from the male flowers to the females.

Pollen from the male species of a plant will only pollinate female flowers within that same species. However, cross pollination can occur between different varieties within a species. To explain further:

1. Cucumbers are cucumis sativas. You might have cross-pollination occur between different types of cucumbers, but NOT between cucumbers and other members of the cucumis family.

2. Summer squash (zucchini, yellow crookneck squash, pattypan squash, etc.) pumpkins, gourds and some varieties of winter squash are Cucumis pepo. All members of Cucumis pepo can cross with one another. So, a winter squash like acorn squash could cross-pollinate with a zucchini or a pumpkin or a miniature gourd, but NOT with a cucumber (Cucumis sativus) and NOT with muskmelon (which we call generally call canteloupe) which is Cucumis melo.

3. Muskmelons, which we in this country generally call canteloupe even though they are not true canteloupes, are Cucumis melo. Different kinds of muskmelons can cross with one another, but will not cross with cucumbers (Cucumis sativas) or squash family members (Cucumis pepo).

If crosses occur within the three families, you still will not see any effect unless you save seed from those cross-pollinated offspring and later plant that seed. At that point you might have cross-pollinated fruit appear. That cross-pollinated fruit will likely have some characteristics of each of its parents and may not produce fruit worth eating.

People who like to save seed have to plant in certain ways to get uncrossed seed. For example, they can plant the members of the same family a certain distance apart to prevent pollination, say, maybe a quarter-mile apart or so, but even that is no guarantee. They can build boxes or cages from wood and window screen-type mesh or cover the plants with fabric row cover to prevent cross pollination. Or, they can bag the blossoms with fabric bags. If you box your plants, cover your plants with row covers, or bag your blossoms, you have to manually pollinate the flowers yourself by transferring pollen from the male flowers to the female flowers and then replacing the cover that isolates them from natural pollinators like bees.

If cross-pollination between species doesn't occur, why does this old garden myth persist? Probably because it is an easy and believable answer for common problems with these plants.

For example, if cucumber plants are subjected to low soil moisture or to some other form of stress, like very high temperatures or low soil fertility, you may get cucumbers that are misshapen and have a somewhat gourdy appearance. But this strange appearance does not mean the cukes crossed with a gourd, just that the soil fertility is too low, or moisture levels are either extremely high or extremely low or the temperatures are too high.

If muskmelon (aka canteloupe) fruits lack flavor, which is a common problem in home gardens, cross-pollination is often falsely blamed when the actual problem is usually due to overwatering and/or overfertilization.

If squash family plants produce poor fruit that shrivels and falls off the plant without growing and enlarging, cross-pollination is often blamed, when the actual problem was a lack of pollination. Remember that the male flowers have no fruit at their base and the female flowers do. Well, if pollen from that male flower doesn't make it to the female flower, those little fruit remain unpollinated and fall off the plant after a few days.

If squash family members produce fruit that is misshapen or multicolored (usually an oddly patterned green and yellow), and the plants have leaves that are also mottled in color and show distorted growth, the culprit is often believed to be cross-pollination, but it is just a cucurbit disease called squash mosaic virus.

If the squash family member 'summer squash' produce fruit that is extremely tough and has hard instead of tender seed, you have left the fruits on the plant too long. Harvest often, every 2 to 3 days, so your summer squash will not be overmature. Leaving the fruit on the plant too long will give you very large fruit, but it will be lower in quality.
Winter squash, however, is supposed to have a hard skin and mature seed, so you do leave them on the plant a long time.

I grow about four dozen different varieties of summer squash, winter squash, pumpkins, gourds, cucumbers, watermelons, cantaloupes and muskmelons every year, so feel free to ask if you have more questions.

And, I am going to post a separate thread on how to grow cucurbits successfully, so you can pick up a few tips there. After all the years I have spent learning this stuff, I'd like to pass on the knowledge.

Happy growing!

Dawn