Some have oily coats and need detergent or peroxide soaks. Some seeds need the daily change from warm to cold that occurs in spring and fall, and they germinate best sown in pots and exposed to outdoor conditions. Get our Gibberellic Acid Information Sheet for brief tips on experimenting with these treatments. Small clean pots are filled with damp, sterile, soiless mix. Milled spaghnum or a light dusting with powdered charcoal discourages fungi and algae.
Seeds are sown and the whole pot is sealed in a plastic bag and placed out of direct sunlight.
This creates a mini-greenhouse and the soil will not dry out and the seeds are protected from mice, etc. Pots can be left for years with no care other than regular checking for seedlings. As soon as seedlings appear, begin hardening off. Bagged pots may be kept under florescent lighting without overheating. The rating of plants according to the hardiness zones in which they will grow has improved greatly over the last 20 years.