Please explain what a plug tray is.
Plug trays are special greenhouse trays for growing large numbers of plants in minimal space. They are commonly made from plastic with individual cells arranged in rows. For example, Richters uses a "128" tray that measures 11 inches wide by 22 inches long and 2 inches high. The tray has 128 cells, each about one inch square. Because there are always a few plants that do not survive, we sell each tray as 120 plants.
Plug tray plants are smaller and somewhat more fragile than potted plants but they are much less costly. For example, a potted garden sage costs $2 while a plug tray costs $40 for 120 plants, or 33 cents each. But being smaller plants they need more care to get established. Timely watering, especially in hot, dry weather, is critical.
Many commercial growers are buying plug trays instead of starting their own plants from seeds or cuttings. Buying plug trays eliminate the need for maintaining stock plants year round. Plugs can be potted up in spring and be ready for sale in as little as four weeks.
We have noticed that many home owners are also buying plug trays. For lavender or santolina hedges that call for a hundred or more plants, plugs are ideal.