In autumn, the ripe pumpkins are harvested when the skin is no longer green, the fruit sounds hollow when tapped and the stem base is hard and woody. You can then store them at home for several more weeks or eat them right away.
Mineral deficiency in the soil
One reason is a calcium deficiency in the soil (similar to stippling in apples). You can compensate this by giving calcium fertilizer during the growth phase.
You can always dissolves calcium effervescent tablets (pharmacy) and administers this mixture by watering can. You can also grind eggshells and mix them into the soil. It is best to water with water from the tap, not with soft rainwater. Rainwater has almost no lime.
A second possibility is that a fungus in the soil is damaging the plants/fruits. If the leaves remain healthy, it should be a fungus that specifically attacks fruit (like Monillia). This is where an antifungal would help, but…you still want to eat the squash! We do not recommend eating after spraying. Even though pumpkins have thick skins, there are still better ways to prevent or avoid a fungal infection.
Five tips against fungi
- Keep pumpkins dry from underneath. Spread straw on the ground or mulch material to keep the fruit from lying on wet soil. Replace the soil for the coming season and provide pathogen-free substrate for the next set of pumpkins
- The climbing varieties can grow up supports. Towards the end of the season, clip the shoot ends from all pumpkin plants. During the fruiting period, additional potash-rich fertilizer or appropriate liquid fertilizer is given every two weeks
- You need to make sure that the plant (leaves and fruits) does not get too wet. So water in the morning at the roots and not with the sprinkler. Fungal diseases develop with preference in a cool, damp environment.
- For a boost, feel free to try a plant liquid manure. These concentrated plant broths are mixed with water and applied weekly. This way you save on fertilizer and garden organically.
- You can also remove some of the lower leaves so that the fruits get enough light. This way the fruits ripen better and dry faster when it rains.