Before you do anything—even before you start dreaming about building a greenhouse—check with your city engineer or building inspector. It is important to know what the building regulations are as to greenhouse placement and construction. In some residential areas, construction of any kind of commer­cial structure is prohibited. Find out everything about all rele­vant laws—and don't consider yourself "too smart" to need a lawyer.

To build a workable greenhouse, you will need a construc­tion plan. Then you can consider ways and means. There are several ways to go about building.

You can draw up a contract with a manufacturer of green­houses to supply all the materials, all the heating and cooling equipment, and the masonry. You can even get him to find you a builder to erect the structure, and also a plumber for the water and heating installations.

Or you can purchase the material you need (new or used), and have some local labor come in and build your greenhouse. Or you can do it yourself, perhaps with some help from your family.

If you prefer the prefabricated units, you can erect a green­house with little or no extra help. You can glaze it with regula­tion glass panes, Fiberglas, or plastic. Ready and able to supply all this are innumerable firms. As you plan your greenhouse, there are further decisions you will have to make.

Where to Place Your Greenhouse

You must decide upon a site, and this involves several con­siderations. You want a location where you can work conven­iently and where there is maximum sunlight. Even though you may plan to start with only shade-loving plants, you will prob­ably find that other kinds are profitable, too, and so eventually you will want to be able to grow light-loving plants. You can always apply shading to make a house darker, but you can't make the sun come around to a greenhouse that has been un­wisely located in a shaded place. Fluorescent and incandescent lighting can be used to raise light intensities in winter and on dark days, and this is a very practical means of utilizing small problem or special-purpose areas (as discussed later). But you certainly don't want artificial lighting to be your primary light source—not while sunlight is free!

Therefore, you want a location with a southeastern or south­ern exposure, and the land should be well-drained. Then, for the sake of customers, you need a location which is easily found, and where parking will be easy.

If your eventual aim is expansion—that is, having a series of greenhouses—plan that series from the very start. Make your first house fit in—on paper—with those you will build later, so as to form a complete unit. Many greenhouse opera­tions start on a small scale but soon need to expand, so select an adequate site at the start.

What Type of Greenhouse?

There is a type of greenhouse to meet every preference, every gardening need, every budget. I have seen sun porches and chicken houses converted into greenhouses; greenhouses built as second-story units over garages; free-standing or de­tached greenhouses; step-into pit houses, and many kinds of attached-to-dwelling ones. There are heated, partially heated, and unheated greenhouses, each successfully designed to suit someone's gardening-for-profit plan.

Greenhouse designs are numerous but types fall into these main divisions: span, lean-to, uneven or partial span, and the pit house, which may be any of these types but with a greater portion of the walls below ground level. If you have plenty of room—real acreage or a large lot—the free-standing span house may be best for you. This type, if properly placed, receives maximum sunlight throughout the day in every season.

A lean-to, as the name suggests, is erected against the side of another building. The partial span or uneven type has a greater distance from eaves to gable on one side of the house than on the other. In the north, the low winter sun comes di­rectly through such a roof for maximum light. And in the summer, when the sun is high, this greenhouse draws light reflection from both sides.

The cost of pit-house construction is low. Many growers use pit houses only during early spring and into fall. They are left idle during the coldest months of the year to avoid a heating bill. Other growers operate a pit house economically by having it dug off the basement and served by the household heating system. This arrangement affords ample space for potting, household tools, and other necessary equipment.

Although curved eaves make a handsome greenhouse, there are no special advantages in them

7. An inside and outside view of a living-room, greenhouse extension— a practical and decorative way to take the first step into growing plants for fun and profit.  (Photographed by Aluminum Greenhouses)

How to Figure Costs

Before you build, get estimates for a number of greenhouse makes and sizes. Manufacturers are glad to send you their "literature." Builders in your own area, and elsewhere, will furnish a price list for partial or complete building. Even your lumber company will help you compute costs of a suitable structure. At the same time, ask for estimates from plumbers for heating and cooling each of the greenhouse sizes under con­sideration. Before you settle for a slightly smaller size than you want, because of costs, remember that a greenhouse is an operating unit, and in the long run the cheapest to build is not always the most economical to run. Get plenty of advice. (Check garden publication advertisements and, for local firms, refer to your classified telephone directory.) Look at other greenhouses, note the complaints of the owners as well as their satisfaction. Here is a general rule to guide you: Labor and material for the small greenhouse usually run higher than for a large one. Hence, the smaller the greenhouse, the higher the cost per square foot.

Today a prefabricated unit somewhat over 8 feet wide and 14 feet long, constructed of first-grade redwood, aluminum, and double-strength glass, costs a little less than $450.00, and this does not include the foundation.

An 8- by 10-foot lean-to, 11 feet high, costs about $300.00.

If you plan to assemble the material yourself, ask for prices on glass in box lots. Purchased this way, it costs much less, and you will have extra lights on hand in case of breakage. One of the large companies in my area sells glass in box lots for ap­proximately 50 cents per light.

Glazing compound (putty) costs about 12 cents per pound, and you will need approximately % pound per light.

By assembling your own materials, you can save 10 to 20 per cent of the cost of a prefabricated structure.

Upkeep and depreciation will depend on the original con­struction and the materials used. Greenhouses made of alumi­num stand for years without seasonal replacement or repairs. Cypress and redwood, though the strongest types of wood for greenhouse use, still will show loosened screws and bolts as well as weather damage with the passage of time.

Basic Requirements

All greenhouses should offer plenty of light and good ventila­tion, and those planned for year-round operation also require efficient heating systems. The glass and frame are actually only part of your greenhouse, which you count on to provide an artificial climate. Heater, ventilators, humidifiers, and perhaps a cooling system, must be considered in almost all greenhouse operations. Requirements will vary with each house, depending on location and nature of the crop or crops to be grown.

The foundation of the house must be strong enough to carry the whole weight and give support against wind and ice. You can use concrete, poured cement, cinder blocks, or Transite. All of these materials have good insulating qualities and will give protection against loss of heat.

The framework may be of aluminum, redwood, or cypress. Aluminum is originally more expensive than wood but involves little or no upkeep. You can purchase either aluminum or wood already cut and grooved for easy installation.

Glass, Fiberglas, or plastic such as polyethylene, are materials used for greenhouse light; 20- to 30-inch panes are preferable. One of the most popular prefabs comes with 24- by 30-inch lights. If using glass, you need not buy Grade A quality. Double-thickness Grade B will suffice. Many old greenhouse books caution against using anything but Grade A, but Grade B has proved entirely practical.

8.  A dug-out  and  shelf-lined  cellar  greenhouse—heated  through  the cellar door—puts a sunny but awkward corner to maximum use. Note also the handy cold frame. (Photograph by Genereux)

9. When one unit proves inadequate, add another. This lean-to green­house, with an extension on one side, gained at least a third more growing space with the addition of an attached, king-sized cold frame.   (Photo­graph by Genereux)

Benches and Shelves

Benches and shelves are other greenhouse requisites. Benches can be built of redwood, cypress, or asbestos with slatted or solid surfaces. Some growers set their plants directly on the bench. In my benches I use galvanized tray-inserts holding a 2-inch layer of pea rock on which I set the potted plants. Some growers construct a wooden tray for the bench and put soil in this tray so that plants can be grown directly in the bench. You may prefer to place sand in the tray and plunge pots into the sand. If the sand is kept moist, it provides extra humidity and keeps pots cool.

An asbestos bench 3 feet wide, up to 49 feet long, with 6½-inch sides, including pipe and fittings, retails for about $4.00 per linear foot (or at least it did when I bought one a while ago).

Shelves can be of glass or wood. You can purchase ready-made ones, or start out by making a few of your own and add­ing more as your operation expands.

Greenhouse Walk

For a walk between the benches, use a cement slab, flag­stone, wooden slats, pebbles, or gravel. My walk is a cement slab, and I find it satisfactory since it is easy to wash down.

Potting Bench and Storage Cabinets

You must decide on some form of potting bench, and it will be easier if you allow room for it in your original plans. If you cannot bear to give up greenhouse space for working instead of growing, and if your greenhouse is attached to your house, you can probably do as I have. The greenhouse door opens into our utility room, in which I have a cabinet with a 5/2-foot base. The counter of this cabinet is used for potting, the shelves hold pots and potting equipment. In the greenhouse annex (between the utility room and the greenhouse proper), I have another cabinet for supplies such as fungicides, insecticides, labels, and fertilizers.

Some growers use a garage area for potting and storing ma­terials. This works out fine if your garage is heated or you live in one of the warmer areas; otherwise, it may prove impractical since much potting must be done in winter.

If your greenhouse does not have room for a potting bench, the basement of your home may offer a convenient area.

In any case, make the potting bench as strong as possible for it is destined for hard usage. Transite makes an excellent table top; or you can construct a top of ¾-, 1-, or 2-inch lumber. Actually, even if you expect to be dumping a bushel or two of soil on the counter at a time, the ¾-inch top will serve you well.

About Electricity

Be sure to include enough electrical outlets in your green­house. You may need extra lights, soil cables, or emergency heating, and it is provoking—and possibly dangerous—to have to run an extension cord to an outlet in your house to get ade­quate power or light.

In the small greenhouse the cost of electricity can usually be held to a minimum. By operating without growing lights (artificial lighting units) and soil cables you will have only the cost of a light or two for working after dark. If you install fluorescent lights, you can figure this additional operating cost —varying with the locality—at approximately 1/4cent per hour for two 40-watt tubes. A 100-watt incandescent bulb burns at about 1/3 cent per hour.

Propagating Cases

You can convert one end of your growing bench into a propa­gating case by installing an electric soil cable. And in this area you can raise any plants requiring bottom heat for growth. To create the "case," place a piece of glass over the planting; or you can have a glass frame made to fit over the cuttings. A plas­tic propagating case would also be good.

About Water

Include hot as well as cold water in the plumbing plans for your greenhouse. A mixing faucet will make it possible for you to draw water of proper temperature at any time for your plants.

There is no need to pipe softened water into your greenhouse, unless you want it for hand-washing. Most types of artificially softened water should not be used on plants. While it may do them no immediate harm, it may gradually weaken cell struc­ture and lead to plant collapse.

Copper piping is satisfactory for use in the greenhouse. I have some in mine, and it has never caused any "copper poison­ing." Experts at the University of Minnesota assure me that water passing through copper pipes is perfectly safe to use on all types of plants.

Where to Get Soil

Unless you have planned this greenhouse for a long time and have a supply of good soil ready, the soil required for your first year's planting may have to be included in your budget. More than just plain garden soil is needed for potting most greenhouse-grown plants. Garden or field loam can make up as much as a third of the mixture, but it should be enriched with another third of organic material.

10.   The  perfect  adjunct  to  a  home   greenhouse,   this  cheerful  annex affords space for paper-work, potting, and ample storage. A brief but distinct listing of cultural reminders—easy to keep current on a black­board—is always a good idea. (Photograph by Gottscho Schleisner)

11.  Mrs.   M.   S.   Holman  of  Hampton,   New  Hampshire,  reaps  a  tidy return from this small free-standing greenhouse. Note extra ventilators at sides.   (Courtesy Flower & Garden)

Vermiculite or sand is the other third. With an established compost pile or a heap of leaf-mold, you will find it necessary to purchase only such organics as sphagnum moss, peatmoss, or peat. Sphagnum moss whole­sales at about $2.00 a bale plus shipping charges; granulated peatmoss and horticultural peat at approximately $1.25 per 2½ bushel bag. Leafmold is priced at $1.00 to $2.00 per bushel —more or less—depending on source of supply. Special potting materials such as osmunda fiber (an old-time medium for or­chids ) cost in the neighborhood of $8.00 per bale plus shipping charges; shredded wood and bark, used increasingly of late in orchid culture, is (or was) priced at about $4.00 per 60-pound package.

For starting seeds and cuttings you will need vermiculite at about $2.00 per 3¼ bushel bag; and milled sphagnum at $3.00 per 25-pound bag. Remember, please, that in all cases the prices cited in this book represent purchases I have made at various times. They are not to be taken as gospel.

Pots, Flats, Stakes, and Labels

Pots and flats must be considered also. Your first batch may be donated by friends with a garage full and to spare. But this source of supply eventually runs out. The wholesale price on pots is about 40 per cent less than the retail price. My flats cost me nothing—you may be able to get some from a tile company as I do. Wooden tile boxes are well constructed and long last­ing, even in the moist air of the greenhouse. Of course, you can make your own flats—out of scrap lumber. Some amateurs be­gin with orange or apple crates, but these are of such poor quality and so full of openings that much time and material must be expended to make them usable for even a few months.

When I bought them, No. 1 white cedar flats of good quality, 14- by 20- by 2½-inches, cost about $25.00 per hundred; smaller sizes, say 5- by 11- by 5-inches, were about $16.00. Wooden plant bands used for growing many types of seedlings cost from $5.00 to $6.00 a thousand, depending on size and mate­rial. As you progress in your growing, you will need such things as stakes (for tall plants) at about $3.00 per thousand in the 18-inch size, and wooden or plastic labels at $3.00 to $5.00 per thousand.

What Is Your Time Budget?

You can get a rough idea of the amount of time your green­house plants will require by judging how long it takes you to care for your house plants. Here are some labor-saving devices: guard against dry soil by burying potted plants in damp sand, peatmoss, or sphagnum moss; automatic feeding; constant mist systems; constant water-level watering systems; automatic ventilators, and, of course, thermostatically controlled heat—all discussed later. And there are many plants like wax begonias, annuals, herbs, and episcias which can be grown throughout their life cycle in flats, thus saving much watering and trans­planting time.

Cost of Help

The money you spend for outside help will vary with the size of your greenhouse, the number of plants grown, and the amount of time you and your family care to devote to your venture.

For spring house-cleaning and fall restocking, or at espe­cially busy times, you may be able to get help from school chil­dren during vacations or on Saturdays. A neighbor usually helps me with the spring cleaning, and I pay her $1.25 per hour. The two of us can clean the house in one day.

A man helps me with fall restocking and removal of heavy pots from the outdoor garden to the greenhouse. He charges $1.50 per hour and, again, we finish the job in one day.

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