Peat pellets are compressed, dried disks of growing medium, typically made from sphagnum peat moss or coconut coir, encased in a fine, biodegradable mesh. These small, self-contained units are commonly used for indoor seed starting because they offer a clean, convenient way to germinate seeds and nurture seedlings. They simplify the initial growth phase by providing a stable, sterile environment that minimizes the mess associated with traditional potting soil mixes. This compact system is designed to reduce the risk of transplant shock, making the transition to a garden or larger pot easier.
Preparing the Pellets for Use
The first step involves hydrating the compressed pellets, which requires placing them in a watertight tray with the pre-formed depression facing upward. Pouring lukewarm water over the pellets is recommended, as the slightly higher temperature accelerates the absorption process. The pellets will begin to swell rapidly, expanding up to three times their original height as the growing medium rehydrates within approximately 10 to 20 minutes.
It is important to ensure the pellets fully saturate, creating a stable, cylindrical plug of medium held together by the outer netting. Once the pellets have finished expanding, carefully pour off any excess standing water from the bottom of the tray. The goal is a medium that is damp and uniformly moist, not one sitting in a pool of water, which could lead to anaerobic conditions and fungal growth.
Sowing Seeds and Securing Cuttings
After the pellets are fully expanded and the excess water is removed, you can proceed with planting the seeds or securing small cuttings. Most pellets feature a small, pre-formed indentation at the top center for seed placement. For most common garden seeds, the appropriate planting depth is generally two to three times the diameter of the seed itself.
A common practice is to sow two or three seeds per pellet to account for potential germination failures. Once the seeds are placed, gently cover them with the surrounding peat or coir medium from the top edges of the pellet. If starting small, non-woody stem cuttings, insert the cut end into the center of the moist medium, ensuring good contact with the pellet material. If multiple seeds germinate, the weakest seedlings must be thinned by carefully snipping them at the base, leaving only the strongest plant to grow.
Post-Planting Maintenance
Following the planting of seeds, the environment must be carefully controlled to encourage successful germination and early development. A transparent humidity dome placed over the tray traps moisture and maintains the high humidity required for seed sprouting. This dome also helps regulate the temperature, which is often best kept slightly elevated, ideally between 70 to 85 degrees Fahrenheit, depending on the seed type.
Once the first shoots emerge from the medium, the humidity dome must be removed immediately to prevent damping-off disease, a common fungal issue. The newly sprouted seedlings require strong light, often provided by a dedicated grow light positioned just inches above the tray, to prevent them from stretching and becoming weak. Moisture management is ongoing; the pellets should be checked daily and kept consistently damp by adding water to the base of the tray, allowing the medium to wick the moisture up.
Transplanting the Seedling
The seedling is ready to move to a larger container or the garden bed when it develops its first set of true leaves and the roots begin to visibly emerge through the pellet’s outer netting. The advantage of the pellet system is that the entire unit is transplanted, which minimizes root disturbance and transplant shock. Dig a hole in the new location that is slightly deeper than the height of the pellet.
The netting surrounding the pellet is designed to be biodegradable, but its breakdown rate can vary depending on soil conditions. To ensure the roots expand quickly into the surrounding soil, gently tearing away the top third of the mesh is recommended just before planting. This action releases the root crown without destabilizing the main root ball. Plant the entire pellet, ensuring the top surface is covered by a thin layer of soil to prevent it from drying out quickly.