Warm desert plants and tropicals like warmth. Oscillating temperatures are occasionally required by plants. Desmanthus illenoensis for instance germinates best when the nights are rather cool, and the days are warm. Mimicing this indoors requires that seeds are shifted from the refrigerator to the counter in the morning, and back again at night. Time Until Germination Average range of time to germinate is usually given in weeks.
Time varies with temperature, so expect considerable variation.
These will stand some frost and can be sown direct to the garden as soon as the ground can be worked, March to June. Prepare the soil until a smooth, fine surface is obtained. An attractive annual border can be had by planting in large, irregular drifts. These are killed by frost and should be sown in late spring after danger of frost. For ealy bloom, start early indoors and plant out after danger of frost.