Pumpkins are a warm-weather crop that is usually planted in early July. The specific conditions necessary for growing pumpkins require that soil temperatures 8 cm deep are at least 15,5 °C and that the soil holds water well. Pumpkin crops may suffer if there is a lack of water or because of cold. Soil that is sandy with poor water retention or poorly drained soils that become waterlogged after heavy rain are both detrimental. Pumpkins are, however, rather hardy, and even if many leaves and portions of the vine are removed or damaged, the plant can very quickly re-grow secondary vines to replace what was removed. Pumpkins produce both a male and female flower, which much be fertilized, usually by bees. If there are not enough bees for polination, gardeneres often have tand pollinate. Inadequately pollinated pumpkins usually start growing but abort before full development.
Pumpkins grow best when the soil pH is close to 6,5. When the soil pH is adequate, the availability of both major and minor nutrients is maximized. Pumpkins are very nutrient extracting crops, thus high nutrient amounts must be applied, especially nitrogen and potassium. Pumpkins are able to absorb nitrogen in two forms, ammonium (NH4) and nitrate (NO3), but they do prefer the nitrate form. Higher rates of N may push foliar growth at the expense of flowers and fruit. A large canopy seems to shade female flowers and makes it difficult for bees to find them for pollination. Like nitrogen, phosphorus can be found in organic and inorganic portions of the soil. The typical deficiency symptom is a purplish color on the leaf undersides. The unavailable forms include phosphorus in organic matter and phosphorus fixed or bound to iron and aluminium at low pH, and calcium and magnesium at high pH. Banding phosphorus rather than broadcasting is a more efficient way to apply this nutrient. Plants absorb potassium in the ion form K+. Potassium can be leached from sandy or gravely soils and be fixed and unavailable in the clay portion of the soil. In severe cases, leaf edges may be scorched. Calcium is absorbed by the roots in the ion form Ca++. Although calcium may be present in high levels in the soil, dry conditions will limit its uptake by the plants and cause deficiency symptoms. High levels of sodium, potassium, magnesium, and ammonium may also cause deficiencies. Magnesium is absorbed in the Mg++ form. A deficiency is most common on acid, highly leached soils that are high in potassium or calcium.
NovaTec® Solub 14-8-30 is recommended in fertigation systems from an early stage until first fruit picking, while NovaTec® Solub K-Max (10-5-30) seems perfect to be applied for the rest of its fruit development cycle until reaching senescence. Additionally, applications of NovaTec® Amino Fluid in 2 week intervals may improve yield. A foliar application of Basfoliar® Kelp SL and Vitanica®Si may improve fruit production and crop balance into the generative stage.