Seed - sow spring in a cold frame. Seeds can be sown in a cold frame. They are best germinated using a cold frame. Propagate by seed sown as soon as the seed is ripe into a cold frame. It can be grown in a greenhouse and cold frame. Some advise to sow in early autumn in a cold frame. Although it grows best within a cold frame or alpine house. A miniature greenhouse is known as a cold frame. The name itself exemplifies the distinction between the warm greenhouse and the unheated cold frame. They are then grown for another year in a greenhouse or cold frame. They then can be grown in the greenhouse or cold frame for their first year. Sink pots in winter or store in a cold frame for insulation. They should be planted into beds or trays in a cold frame. Stored seed is sown early in the year in a cold frame. A walipini is an earth-sheltered cold frame.