1. Q. What causes my pumpkin to produce very few fruit?
A. Poor fruit set on pumpkin is commonly caused by having the plants too thick which produces too many leaves which discourages pollinating insects. Like other members of the cucurbit family, pumpkins require bees for pollination. They produce male and female flowers and pollinating insects must transfer the pollen from the male to the female flowers for fruit set to occur. Also, wet, cloudy conditions which slow insect activity will greatly reduce fruit set.
2. Q. Will pumpkins cross with squash, watermelons or cucumbers resulting in off-type fruit?
A. Varieties of the true pumpkin readily with each other, but this crossing will not be apparent unless seed are saved from this year's fruit and planted for next year. Pumpkins will not cross with varieties of true squash. All varieties of "summer squash" are in reality true pumpkins and will cross readily with each other and with other pumpkins. If you grow both summer squash and pumpkins in your garden, you should not save seed for planting in next year's garden.
3. Q. Will it help to remove the tips of my pumpkin vines late in the season to encourage fruit size?
A. The tips of vining pumpkins may be removed about 45 days prior to the anticipated first fall frost to discourage plants from further spreading. This practice will generally encourage larger fruit and will not harm production as any additional fruit which might set after that time will not ripen before the first killing frost of the fall.
4. Q. When I raise pumpkins in the fall, the foliage becomes covered with a white, powdery, dusty material. What can I do to prevent this?
A. This is powdery mildew. It is an airborne fungus and grows on the outside layer of cells of the leaf. It can be controlled with sprays of benomyl if applied early and on a regular schedule. There are no varieties resistant to this disease, and if the disease is not controlled, it can kill the plant.
5. Q. What is the difference between a pumpkin and a squash? I need to know so I can impress all of my ghostly friends on Halloween.
A. The genetic history of the pumpkin is so intertwined with the squash and the gourd that it's sometimes difficult to tell them apart. Generally speaking a pumpkin is something you carve, a squash is something you cook and a gourd is something you look at. Though it's really not that simple, it's also not that difficult. The answer is in the stem.
Pumpkins and squashes and gourds all belong to the same genetic family - Cucurbita. Within that family are several species or subgroups - Cucurbita pepo, Cucurbita maxima and Cucurbita moschata.
The pepo species is usually recognized as the true pumpkin. Varieties within this group have bright orange skin and hard, woody, distinctly furrowed stems. But the group also includes gourds, vegetable marrow, Pattypan summer squash, scallop summer squash, gray and black zucchini and summer crookneck squash.
The maxima species also contains varieties that produce pumpkin-like fruit but the skin is usually more yellow than orange and the stems are soft and spongy or corky, without ridges and without an enlargement next to the fruit. They don't really make good handles for jack-o'-lanterns. Varieties such as Atlantic Giant, Big Max and Show King are often listed as pumpkins but are more properly called pumpkin-squash or squash- type pumpkins. Other members of the maxima group are Hubbard squashes, banana squashes, buttercup squashes and turban squashes - in short, most autumn and winter squash.
Finally, there's the moschata species. Varieties in this group are usually long and oblong instead of round and have tan rather than orange skin. The stems are deeply ridged and enlarged next to the fruit. Ironically, a member of this group is used for much of the canned pumpkin sold in this country. Other non-pumpkin members include the squash-like cushaw, winter crookneck squash and butternut squash.
Insects - Pumpkins have the same insect problems as squash.