This can be done by placing them into a coldframe for a week before planting. However, if you don’t have a coldframe then move the plants outdoors during the day and bring them back indoors overnight. Then the following week leave them out there for the whole time in a sheltered spot.
Plant out in a position with moist but well-drained soil. They are thirsty plants too, so it’s a good idea to sink a plant pot or bottle next to their planting spot to allow water to drain down to the roots. To boost fruit growth feed the squashes every 10-14 days with a fertiliser that’s high in potash when flowers appear.
Most varieties will produce fruits approximately 15 weeks after sowing the seeds. For summer squashes, these can be harvested when the fruit is quite small and immature – these don’t tend to store as well as winter squashes. Winter squashes can be left to mature on the plant, then harvested before the first frost.