Do we have a climate for pumpkins?

Pumpkins, which have a number of meanings and quite a few benefits, are a very popular vegetable in our country. They originated in America and have always been considered a symbol of eternal life, resurrection, fertility and fertility. Already the Celts believed that the night before All Saints’ Day was a time of transition, during which the veil separating the worlds of the living and the dead fell. During this time, they would place hollowed-out vegetables in front of their homes – originally turnips, rutabagas, potatoes and beets, but now mainly pumpkins – with menacing faces cut out and candles inside to ward off wandering spirits.

Pumpkins, in addition to their characteristic shape, also have a positive effect on our health. In order for us to enjoy the unique taste of this vegetable and benefit from its health-promoting properties, we need to provide it with the right conditions, including water. Will the increasingly observed water shortages and droughts allow to maintain the production of this vegetable in Poland? Will pumpkin adapt to climate change and thus not become a luxury?

What we know about pumpkin

Pumpkin is an annual plant, belonging – along with about twenty other species – to the cucurbit family. Its fruits, usually yellow or orange, often assume colossal sizes – up to 200 kilograms! As for its taste, its greatest advantage is its versatility and neutrality. It is often used for preserves or as a decoration.

The species most commonly found in Poland are the giant pumpkin (which can grow up to 800 kilograms), the musk pumpkin and the common pumpkin. The former is native to Central and South America. It was cultivated as early as 3,000 BC. It probably derives from the wild species Cucurbita lundelliana Bailey and Cucurbita martinezii Bailey.

It came to Europe via Spanish sailors in the 16th century, and was later spread to other continents. Musk pumpkin is native to Mexico or the northern regions of South America (Peru, Ecuador). It was probably the earliest cultivated species of pumpkin (since about 5000 BC). The common pumpkin is one of the oldest cultivated plants, native to Central America and the southern states of the United States. It was grown mainly as a vegetable or forage crop, but the ornamental varieties available today make interesting decorations for garden arrangements. In their composition, pumpkins contain a lot of water (about 95 percent), carbohydrates and protein.

Climatic conditions favorable for pumpkin

Pumpkins are extremely thermophilic plants, mainly because they come from the subtropical climate zone. They are sensitive to frosts – the problem is already 0°C, and prolonged cooling leads to the death of young plants. A drop in air temperature below 10°C results in dropping of buds and even overcooling of shoot tops. Pumpkin during the growth period needs a lot of water – it is advisable that the rainfall is at the level of 400 mm (throughout the growing period of the pumpkin).

Growing pumpkins

Pumpkin has several growing requirements. It is a thermophilic plant – for proper development it needs adequate space and a sunny position. It grows best in places sheltered from the wind, on permeable, humus and fertile soil, with neutral pH and good air-water relations, maintaining humidity (80-90 percent), preferably with a not too high level of ground water (80-90 cm). From June to July it is recommended to fertilize the pumpkin with a compound or organic fertilizer. Harvesting of pumpkins depends on the variety – it begins in September and lasts until the first frost.

Water needs of pumpkin

The high water requirements of pumpkin are due to the production of a huge amount of fresh mass in the growth process, a large evaporation area and a shallow root system. They need most of it during flowering and fruit setting and growth – about 400 mm of rainfall or irrigation with this amount of water. For a satisfactory yield, pumpkins need 1000-1500^{m3 of} water per hectare. Seedlings are irrigated every 2-3 days, preferably with distilled, lukewarm water. Water the soil, not the leaves, to reduce the risk of fungal diseases.

With water shortage, fruits do not grow and become less juicy, and the yield decreases. This is because fruit buds turn yellow and shrivel, dry matter content and sugars increase. Excess water is also unfavorable, as it causes intensive vegetative growth of plants and rotting of fruit buds.

Pumpkin responds well to soil moisture at 80-90 percent of field water capacity. Ideally, it should remain at a constant level up to about 50 cm for about 2 weeks before harvest. Reducing humidity during the harvest period improves the ripening and consumption value of the vegetable. Too high, prolonged soil moisture causes root hypoxia, increased pH (pH), poorer uptake of magnesium and micronutrients, and therefore a decrease in yield quality.

Pumpkins and their health properties

Pumpkin is a versatile vegetable. It is an ingredient, and often even the basis, of soups, sauces, cakes, salads, pates, purees and preserves. Giant pumpkin and musk pumpkin are characterized by properties that are not only flavorful, but also medicinal and even cosmetic. Edible are not only the fruits, but also the seeds and flowers.

Pumpkin fruits are valued for their easy digestibility, low calories and health-promoting properties. The flesh contains β-carotene, which has beneficial effects on heart, brain and memory functions. In addition to it, pumpkin contains a lot:

• Carotenoids – provitamin A (mainly β-carotene), which is most abundant in those with yellow or orange flesh;
• vitamins: C, E, K, PP, as well as B1, B2, B6;
• folic acid;
• mineral elements: K, P, Ca, Mg, Na, Fe and Zn.

Pumpkin seeds contain 35-50 percent oil on a dry weight basis, rich in Omega-3 unsaturated fatty acids. The seeds also contain phytosterols, easily digestible protein, dietary fiber and β-carotene. Their GI is 25. Fresh pumpkin seeds, thanks to their kucurbitacin content, help get rid of pinworms, tapeworms and other parasites.

Pumpkin is a source of fiber useful in preventing constipation and lowering cholesterol levels. Its consumption supports the maintenance of healthy skin, promoting the healing of the epidermis and preventing the aging process. A major advantage of pumpkins is that they do not store heavy metals, so they can also be used in the nutrition of young children.

Pumpkin – superstitions

The pumpkin, which wards off evil spirits on Halloween, also has a number of other purposes. In the past, it was considered a symbol of eternal life, fertility and harvest, as well as a metaphor for light.

Since it has many meanings, many superstitions have arisen based on it.

• To ensure good luck and abundance for the household, place a pumpkin at the threshold of the house.
• To ensure fertility and abundance of crops, on All Saints’ Eve, pumpkin seeds should be buried in the field where you plan to grow.
• To ensure money, carry an odd number of pumpkin seeds in your wallet – such a seed heralds a fortune.
• Burning a few pumpkin seeds will protect household members from unexpected accidents.
• Pumpkin can help wean us off people who affect us badly.
• In some regions of Poland, before the wedding night, the groom would bite into pumpkin seeds and then… put on a pumpkin mask to make sure he would live up to his marital duties….

Pumpkin as decoration

Pumpkin, because of its color, shape and size, is increasingly used as a decoration. Most of us find it difficult to imagine autumn decorations without it. It adds charm not only to gardens, vegetable beds or terraces, but also to rooms. Pumpkins, placed in pots or wicker baskets on the terrace or veranda and combined with heather, chrysanthemums and decorative cabbage, create impressive autumn arrangements. When the flesh is hollowed out and various patterns are cut into the skin, and candles or LED lamps are lit inside, they create atmospheric lighting. After the season, the leftover pumpkin is worth composting – in the spring it will be a valuable source of nutrients for the soil.

In the coming time of autumn nostalgia, let’s not forget about pumpkin. The question remains, however, whether pumpkin will adapt to the changing climate in an era of increasing extreme events, such as water shortages and droughts.

Methodology for integrated production of giant and musk pumpkin (first edition) approved under Article 57 (2) (2) of the Law of March 8, 2013 on plant protection products ( OJ. of 2020. pos. 2097 as amended.) by the Chief Inspector of Plant and Seed Protection, January 2023.