The great advantage is that you can see exactly what you are buying. As plants are usually sold in containers you can buy perennials at almost any time of the year. The stock is large and varied. Against all the obvious advantages you must recognize that container-grown plants are more expensive than lifted ones and that you generally need a car to get there. You also cannot expect them to stock all the plants listed in gardening catalogues. You will have to write to a specialist nursery to obtain these species. If something goes wrong take the plant back to the garden centre and explain the situation. Always keep your receipt. If it is not your fault the garden centre will usually replace them.
In hardware stores, garden shops, department stores and supermarkets you will find a selection of favourite varieties when the planting season arrives. The popular bulbs will be available in spring and perennials will be on offer in autumn and spring. Bedding plants will be there, but don't expect to find unusual varieties. There are advantages, you can pick up a few items when doing the shopping and the prices tend to be inexpensive, but the warm conditions can lead to drying out and premature growth. If something goes wrong and it is not your fault then you can try taking the plant back to the shop. The response however will depend on the store and there is no guarantee of replacement.
Bedding plants and bulbs are bought from market stalls throughout the country. They tend to be the cheapest source of supply and the plants are not kept in overheated conditions. But do take care. A great deal of inferior planting material is sold in this way and you will only have yourself to blame. Feel the bulbs to make sure that they are firm and do not buy boxes of bedding plants if they are in full flower. The golden rule is to buy from a market stall at the beginning of the planting season. If something goes wrong, there is usually very little chance or redress. It would be surprising indeed if the stallholder admitted that his bulbs were diseased or that his plants had not been hardened off properly.
Despite the advantages of the garden centre, there is still a place for the reputable mail order nursery. You can make your choice at leisure, checking the plant's requirements before filling out your order. In the specialist catalogues you will find varieties unobtainable from your garden centre. For ordinary gardeners there is the distinct drawback of not being able to inspect before purchase. Also the stock may arrive when the weather is unsuitable for planting. If something goes wrong, write to the company and explain what has happened. Many nurseries will return your money or send a credit note if they feel that your complaint is genuine.
National newspapers and gardening magazines often have advertisements for 'bargain' offers. Good value offers do sometimes occur but such advertisements must be viewed with caution. Avoid taking all the glowing descriptions too literally. If money is short and you have a large space to fill, the 'bargain' collection is a money saving way of stocking up with popular varieties. If the stock is dead or badly diseased write the company and also to the newspaper where the advertisement appeared. If the plants are small and there are just a few spindly stems compared to the robust plants offered for sale at your local garden centre, then you have no grounds for complaint. It was a 'bargain' offer and you have no right to expect top grade plants.