From Cloches to Castles–Season Extenders

Season-Extending Options for Every Budget

(This article first appeared in The Gateway Gardener Jan/Feb. 2006 issue)
a picture of a WallOwater device for warming plants in cold weather

WallOWater, photo courtesy Charley's Greenhouse Supply

Many gardeners welcome the respite from gardening chores that comes from the frosty days of winter, but if this is your season of discontent, there are many options available to minimize and even eliminate your gardening downtime.  From simple, economic covers to budget-busting glass castles, here are some season-extending strategies you can use to get the most out of your garden.

Cloches and Row Covers

Frequently, spring and fall will bless us with plenty of nice, warm weather, interrupted only occasionally by dangerous drops in temperatures. You don’t need permanent protection for these conditions, just something you can quickly throw over tender plants to insulated them from the wind and cold. Cloches and row covers are ideal tools for gaining up to 5 additional weeks of production at both ends of the season for cool weather crops like spinach, peas, lettuce, and broccoli.

a picture of a cloche for warming plants in cold weather

A cloche, photo courtesy Charley's Greenhouse Supply

A cloche (pronounced klosh) was originally a bell-shaped glass jar placed over tender plants when temperatures would fall into the danger zone, but in practice can be anything that will serve a similar purpose.  When used to protect single plants, they’re called hotcaps. You can use something from your home, like glass jars, the bottoms of clear plastic soda bottles or milk jugs, or purchase simple wax cones, attractive Victorian-looking bell jars, or water-filled plastic tubes (Wallo’Waterä). Keep in mind that some materials will provide more protection and more light penetration than others. Be sure to remove or prop up protectors on warm, sunny days to provide air circulation and prevent steam-cooking your plants.

Cloches can also be made or purchased that cover several plants or entire rows. Also called row covers, mini-hoop-houses or tunnels, they can be made from flexible fiberglass panels arched over the rows and secured, or from sheet plastic draped over arched PVC,   aluminum or bamboo hoops. Like hotcaps, these structures should be designed to be removable during warmer days to avoid plant damage.

Floating row covers are being increasingly used to extend seasons for vegetable growers. These are long sheets of breathable polyester material that are laid over rows of young transplants. As the plants grow, they simply push the material up. Not only do floating row covers provide protection against frost and wind, they have also shown to protect from certain insect pests, reducing pesticide use. Row covers should be removed whenever temperatures beneath them exceed 80ºF.

Cold Frames and Hotbeds

a picture of a cold frame for keeping plants warm in cold weather

Cold frame, photo courtesy Charley's Greenhouse Supply

Cold frames are often used as temporary homes for hardening off potted plants and seedling trays, or to get a head start or prolong the harvest for cool-weather plants like pansies, lettuce, spinach and cabbage. They can be purchased or homemade, and generally consist of a wood, metal or synthetic frame with a hinged window sash or other clear material for the cover. Instructions for building a cold frame can easily be found on the internet (see, or in books such as Ortho’s All About Greenhouses.

Hotbeds are simply heated cold frames. Conventionally, hotbeds were heated by building them over buried beds of raw manure that would provide heat as it fermented. Today, urban and suburban dwellers usually opt to install electric cables or steam tubes to provide a more convenient heat source. Other designs include a water barrel or other water reservoir that captures solar heat during the day, releasing it at night.

In either case, place the structure in a location where it will receive plenty of sunlight, good drainage, and wind protection, and be sure to “pop the top” on warmer, sunny days.


If you think greenhouses are only for the rich and famous, consider that greenhouse structures come in all sizes and price ranges, from simple collapsible plastic hoop houses and portable huts to elegant, elaborate greenhouses for the serious, deep-pocketed gardener.

Hoop houses are simply large, walk-in cloches, constructed with PVC or aluminum hoops that are arched in half-circles and anchored, then draped with plastic sheeting. Hoop houses are typically used by professional nurseries and produce growers, but can make for an inexpensive, temporary season extender for the home gardener.

Easier to assemble and a little more attractive are the lower-end portable greenhouses. These can be found in mail-order catalogs as well as well-stocked garden centers and horticulture supply stores. Featuring collapsible metal framing and woven polyurethane covers fitted with doors and vents just like glass greenhouses, these unheated portable greenhouses are really just walk-in cold frames, but their affordability puts them in the range of even the most frugal gardener.

a picture of an economical home greenhouse

An inexpensive greenhouse, photo courtesy Hummert International

Finally, for the well-heeled gardener who wants year-round protection for those favorite tropicals, tasty homegrown tomatoes in January, and flats upon flats of bedding plants for spring, there’s nothing like a real glass, heated permanent greenhouse. Even here, though, there are endless options and prices. In addition to size, which is limited only by your budget, there are choices of framing material between steel, aluminum or wood; covering materials of polyethylene, polycarbonate or glass; free-standing or lean-to; standard models or custom.

Small, unheated 6’x6’ hobby greenhouses with polycarbonate panels can get gardeners started for around $700-1,000, but expect to pay around $4,0000-6,000 for an 8’x10’ model with double or triple-glazed glass panels and heavy-duty framing construction. Start adding square footage and accessories like heaters, benches, thermostats, automatic venting, fancy Victorian crests and finials, and, well, you’re not in Kansas anymore.

Plus, while the smaller, simpler models can usually be assembled by a handy homeowner, larger, more elaborate designs may necessitate the help of a contractor and may require a building permit. In either case, before you buy, do your research. There are so many options available, make sure you get the right structure for the type of gardening you want to do.

Whether you want to get a head start on spring, get a few more weeks out of your late fall vegetables, or garden right on through the winter, there’s a season extender that’s just right for you and your budget.