Squash and pumpkins will expand to fill the available space, I find. If you put them in the garden they will run riot all over the garden. If you put them in the allotment then by September you'll find pumpkin stems and leaves trailing across all your beds.
My preferred solution has always been to train them upwards: to give them a climbing frame such as 10cm plastic mesh secured with bamboo canes. With a little initial encouragement and tying in, the plants soon get the idea and ramble upwards instead of out towards the neighbouring plot. I have indeed seen someone use an actual climbing frame, presumably one the kids had grown out of, for this purpose very successfully, but plastic mesh and bamboo will stand up to the task remarkably well.
|Trained upwards, the fruit will hang down from sturdy stems. Off the ground, they stay clean and safe from slug damage.
This year, however, I need the squash to trail along the ground. I'm growing them as the Native Americans traditionally did, alongside climbing beans and sweetcorn in a companion planting partnership known as the Three Sisters. The sweetcorn provides a sturdy stem for the beans to scramble up; the broad-leaved squash will provide ground cover, suppressing weed growth and reducing water loss by evaporation.
|Sowing squash seeds, each one sown 2cm deep in well-watered compost. These survived the cat inspection.
Once all the fruit have been harvested from each of the plants, the green matter can be dug back into the soil for the next year's crop. As well as nutrients from the gradually decomposing greenery, the beans will also fix nitrogen from their roots to feed the soil for the following months.
|Left on the ground, the plants will spread outwards and act as a weed suppressant.
|Slipping a bathroom tile under the developing fruit will keep them some protection from the bare earth.