Outdoor seed sowing…Depending on the variety of seed, most annuals and perennials which can be grown by this method can be planted in seedbeds outdoors. The time for planting varies. A few can be sown in autumn, but most, however, should be sown in spring, and, to be safe, not before the last frost has passed. The big disadvantage of outdoor sowing is that one sacrifices control over the circumstances under which the seeds will germinate.
In an indoor hotbed, or cold frame, conditions of moisture, heat, etc., can be regulated. Not so in the outdoors, where dryness or changing weather can destroy the weaker seeds quickly. If an outdoor seedbed is planned, choose a spot with good soil. Then work in a portion of your compost pile, pulverizing the soil to the depth of 3 inches. Adding some sand and peat moss increases the effectiveness of the bed. Most seed may be planted on the surface, and the deepest one should plant is 1/2 inch. The bed should be well-watered after the seed has been broadcast over the entire area. The bed can then be lightly tamped.
Sowing seeds indoors
The two most important factors in outdoor sowing are soil texture and drainage. Texture is of greater importance in germinating seeds than soil fertility. A mixture of equal parts of good soil, coarse sand and peat moss makes a fine bed. The bottom of the seed pan should be filled with gravel or shards of old flowerpots. The seed should be sown as evenly as possible. As soon as the sowing has been completed, and the soil lightly tamped down, the pan or flat should be immersed in water until the surface shows dark and moist. Excess moisture is then permitted to drain off. This is far superior to overhead watering.
The box should not be allowed to dry out until after the seeds have germinated. Germination will be hastened if the pan is placed in a warm, dark place. As soon as germination takes place, the seedlings should be placed in full light. Shredded sphagnum moss is the best medium for seed germination. Use of it prevents any possibility of “damping-off,” which is a grave threat to all seeds.
Annuals can be grown readily from seed in most cases. The method of growing depends upon the delicacy or hardiness of the seed, and may require planting in frames or pots initially, transferring to the bed only when the weather is sufficiently mild and the plants well grown.
Many perennials and biennials may also be propagated from seed. This method, however, is not suited to all perennials, and some of the methods already discussed will yield more fruitful results. Typical perennials which can be propagated from seed are: