Why Some Plants Start Small: Plugs, Starts, and Soil Blocks
Have you ever picked up a small plant and wondered whether it was truly ready for the garden? Some plants are meant to begin this way, and their size is part of their story. Plants grown at a young age often transplant easily and settle in quickly once planted. Unlike overgrown plants commonly seen at many nurseries, those started at the right time and planted at the correct stage tend to grow stronger and establish more quickly than their traditional counterparts. With the rising cost of plants, starting small can also be gentler on the pocketbook. Unless, of course, you are like me and simply bring home more plants.
Plugs are traditionally known in the wholesale trade as small plants grown in trays that hold 72, 128, 216, or 288 cells. Seventy-two cell trays are the most common size seen in retail seed-starting displays, while wholesale growers often rely on higher-count trays for production. The smaller plant size helps reduce growing costs and provides an efficient way to ship small plants long distances. Trays are a standard tool in commercial growing and allow for a wide variety of plants to be produced. I prefer plug trays for seeds such as lisianthus, sunflowers, and asters. Lisianthus take a long time to grow and prefer very wet conditions early on, which can be difficult to maintain in soil blocks without close attention several times a day. Sunflowers, with their large seeds, are convenient to sow into cells, and since I plant them soon after sowing, trays make the process of sowing and planting quick and efficient.
Nigella, nasturtium, and zinnias are good examples of plants that prefer direct sowing. Growing them in soil blocks offers a great way to start plants that do not like to be transplanted. Soil blocks are small, pressed blocks of soil made using a blocking device. They help reduce transplant shock by air pruning roots as they reach the edge of the block, rather than allowing roots to twist and circle as they often do in traditional containers. Another benefit to soil blocks is reduced plastic use, as no individual containers are needed. Poppies are another good candidate for soil blocks due to their long taproots. The main drawback I have found is that soil blocks require more attentive watering and need to be kept under cover during heavy rain so they do not wash out. They are my preferred growing method for most crops I grow.
The term plant starts is one that many small, local growers use to describe their offerings. It is a broad category that can include plants grown in plastic pony packs, plug trays, or soil blocks, though it is most often used by growers working with the latter two from my observations. What all plant starts share is an emphasis on quality. They are grown with care, timed to transplant well, and intended to establish quickly once they reach the garden.
The growing industry is changing. Large, high-priced plants are becoming less appealing in a tighter economy, while interest in organic and sustainable practices continues to grow. Local growers are helping meet that shift by offering healthy plant starts in a range of sizes, along with a wider selection of specialty varieties. It is a quieter approach than traditional industry, one that values timing, care, and long-term success over instant impact.
