Growing squash vertically on a trellis will save you space in your garden. Squash grows on vines that can spread and take up a lot of space. Wood trellises provide the support needed for the squash to grow because the plants can become quite heavy. Growing the butternut squash on the trellis will also allow you to harvest them more easily and it will keep them off the ground, where they can be more susceptible to disease and insect infestation.
Loosen the soil with a rototiller to 25 cm (10 inches) deep. Mix in 7.5 cm (3 inches) of compost into the soil.
Create 20 cm (8 inch) deep mounds that are 25 cm (10 inches) in diameter with a garden hoe. Space these mounds 7.5 cm (3 feet) apart from each other.
Place a trellis over the mound. Secure the trellis by pushing it into the soil approximately 30 cm (12 inches) deep. A tepee trellis made from wood works well for butternut squash due to its strength. You need a trellis that sits 1.5 cm (5 feet) above the ground with horizontal rungs.
Place the squash transplant into the mounds. You will need one transplant for each mound. The plants need to be centred below the trellis you set up.
Water the transplants to moisten the soil. Keep the soil moist and avoid letting it dry out completely.
Train the squash to grow on the trellis once each plant reaches 15 cm (6 inches) in height. Tie the squash to the trellis with plant ties. Tie the plant ties on the main stem, but avoid tying too tightly. When the squash plant continues to grow, keep tying it to the trellis.
Add a low nitrogen fertiliser monthly to the plant until the growing season ends. Harvest the squash when it matures. The vines will turn brown in colour and appear wilted.