Air column: space within the percussion instrument that determines the pitch. Percussion: sounds produced by striking the instrument with a mallet or stick, or striking one instrument against another. 2. Review the process of forming a hypothesis and making a prediction.
Dig short, shallow rows. The rows should be no more than 1/2 inch (1.5 centimeters) deep and spaced 4 inches (10 centimeters) to 6 inches (15 centimeters) apart. 3. Drop the seeds into the rows. Space the seeds approximately 1 inch (25 millimeters) apart in order to allow the onions enough room to grow and mature.
Done like this, you need to plant the bulbs slightly further apart than you would in a pot with a single layer, so 2-3cm (1-1Â½in) apart is about right. The first layer can go as deep as 28-30cm (11-12in), then cover them over with 5cm (2in) of potting compost, before you place the next layer of bulbs.