Sowing
Follow the instructions on the back of the package or in this Growing Guide. Some large seeds, such as watermelon or squash seeds can be seeded directly into the pot where they will grow until transplanting outdoors. For small seeds like petunias or lobelia, it is best to simply scatter the seed thinly over the surface of the soil and then cover with an appropriate amount of soil. After germination the tiny seedlings can be separated and transplanted into larger containers. Light levels during germination can be important with some flower seed varieties. For example, Petunias and Impatiens seed should not be covered with soil and require light to sprout. Some seeds such as Pansies and Geraniums require total darkness. In that case, cover the flat or container with black plastic and check every day. As soon as seedlings are visible remove plastic and place the flat in bright light. Most plants can be grown in fiber packs with 4-8 seedlings per pack, depending on the plant. Some vegetables, such as lettuce and those in the cabbage family, can be sown and grown directly in 1 inch cells with one plant per cell. Growing in cell packs helps to eliminate root disturbance at the time of transplanting.
Soil temperature refers to the ideal temperature of the soil required to initiate germination. Most seeds germinate at a soil temperature of 18-22°C. Keeping the temperature within this range can be hard, especially for seeds like peppers which take more than a week to germinate. Regular air temperature is generally warmer than the soil temperature, and is not sufficient enough to warm the soil. For best results, try using a propagation mat, heating cable or a hotbed. A really warm room, like a furnace room may be suitable, depending on the seed.
Soil moisture is equally as important as the temperature. The seed needs water to help soften the seed coat and stimulate the root development. Once the root has penetrated into the soil, the young seedling emerges from the soil towards the light. If the soil is allowed to dry during this process, the germination will be delayed or, in most cases, ended. To keep the soil moist, mix the growing medium with water, enough so that if a handful is squeezed, a small dribble of water will run out. After mixing, sow your seeds accordingly and then cover the containers with clear plastic, this can be anything from freezer bags, plastic wrap, or the clear domes which come with some of the large holding trays. Using the plastic covering will help to keep the moisture and humidity in the soil. If you find the soil drying out due to the constant heat, use a water bottle which will provide a fine mist or watering can with a gentle nozzle, so as to not disturb or bury the seed deeper. After germination, be sure to remove the plastic and place plants under grow lights in a bright, south facing window.
