"Fiction belongs in soap operas - not in horticultural advertising." That's the word from the Advertising Ethics Committee of the Garden Writers Association of America, which has been taking a hard look at advertisements for nursery and horticultural products.

Inducements to buy come to the indoor gardener by way of newspaper inserts, magazines and special mailings from catalog houses. A leaflet offering a hanging planter even came inside our egg carton this week.

Exercise some judgment and restraint as you read the advertisements, and look at photographs or sketches of plants and accessories available through mail order.

Descriptions or pictures of houseplants in luxuriant growth are especially tempting, and often give an exaggerated picture of flower and leaf color. While chlorophyll may be your delight, it is often the other "green" that is of prime interest to the advertiser. Be cautious about accepting as fact descriptions of "gigantic," "miraculous," "ever-blooming," "hard-to-find and expensive" plants at bargain prices.

Any time you feel you have been taken, do not hesitate to complain to the place where the ad appeared as well as to the advertiser. Dr. H. M. Cathey, president of the American Horticultural Society, has been working with the fraud division of the U.S. Postal Service to overcome problems related to some of the nationally advertised "horticultural promotions."

It is certainly possible to order and receive satisfactory plants by mail. Some plants are too much of a specialty for local nurseries and shops to handle. When you want to order named varieties or cultivars, it is best to select growers who specialize in the plants you are seeking (for instance begonias, gesneriads, ferns, terrarium plants, cacti and succulents) and who have built up a mail order business based on quality and service. To begin with, send a minimum order. If you are satisfied with what the supplier furnishes, then order the more select items on your list.

In ordering by mail, follow a few simple rules. Carefully read all instructions on the order form and fill it out entirely. The supplier's guarantee should be clearly stated in the ad or catalog.

Usually there will be a statement in the catalog or on the order form regarding delivery date of living plants. On your order, state your preference and also mention whether U.S. mail or United Parcel Service should be used.

Avoid sending cash through the mail, even on small orders. Payment by check, money order or credit card will provide evidence that you have paid for your purchase if there are any questions about delivery of your order. Keep a record of items ordered and keep the advertisement or catalog until the merchandise arrives.

Notify the shipper at once if plant material arrives in bad condition.Most reliable mail order firms will replace material that is in bad shape when received.

A polite letter of complaint should be matter-of-fact (don't rant and rave) and should give all pertinent information, including date of order, items ordered, your check number, etc. Tell why you are dissatisfied and state whether you want a replacement or refund. Ask the company if you should return the item. If you must return an item, insure the parcel so that you have a receipt as proof. Don't assume that the company is dishonest. Ordinarily, firms are anxious to keep customer good will and observe fair practices in dealing with mail order customers.

Many indoor gardeners who grow different varieties of their favorite plant order exclusively by mail from growers who have those specialties.

The plants that are advertised in garish "horticultural promotions" can often be otbained cheaper and in better condition at local plant stores and nurseries, where you can see what you are getting. Take care about the temptations of these beguiling ads.