Tents and tunnels are easy ways to get a head-start on your early spring garden. Both simple structures act like greenhouses, trapping warmth to help your garden grow even when the temperatures outside are cool.
Using tents or tunnels can increase your harvest time by one to two weeks because you can start growing plants under the covers a couple weeks earlier. This is especially useful for areas with short gardening seasons or if you really want to take full advantage of succession planting.
Tents are used to cover individual plants, while tunnels are used to cover whole rows. Tents are often made of paper and fit over a single plant; although they are intended to keep cool air out, ventilation slits are necessary to allow the plant to breathe. Tunnels are usually made of plastic sheets. You can build your own, like a hoophouse, using PVC pipe and sheet plastic.In either case, be sure that the tent or tunnel is tall enough to allow for growth without touching the plants.
Tents and tunnels are used from sowing through germination and can be removed once air temperatures begin to warm up, generally about one month. Before you remove the covers entirely, cut holes in the structures to allow the plants inside to acclimate to outdoor weather for a few days.