Grow tunnels are ideal for overwintering and protecting rows of plants from the frost and harsh weather. If you are looking to protect potted plants or hanging baskets, plant fleece jackets may be a better option. Garden tunnels can also be used to extend your growing season. For example, in the spring time, smaller seedling tunnels can be used to heat up the soil, allowing your seeds to germinate and your young plants to thrive. Later on in the year, you can use larger polytunnels to give your mature plants a few more weeks to grow.