APPENDIX

SOME CHARACTERISTICS OF SEEDS OF A SELECTED LIST OF CULTIVATED PLANTS

The following table lists in the first column the common and Latin names of some common cultivated plants.

The second column shows the nature of the parent plant whether it is an annual, a biennial, or a perennial species. (A =annual, B =biennial, and P=perennial.) Plants shown as A B or B P may exhibit either of the two kinds of behavior, depending on cultural conditions and management.

Most seeds germinate over a wide range of temperatures slowly at the lower part of each respective range and more quickly at the medium to medium-high parts of the range. Relatively high temperature may impede or prevent germination.

The temperatures shown in this table are very favorable for germination of the respective seeds, but are not necessarily the best naturally occurring soil temperatures at which to plant seeds in the spring for the growing of a crop in field or garden. In general, the vegetable seeds shown as tolerant to cool soil must be planted in the spring when soil temperatures are lower than shown, lest the growing crop encounter unfavorably hot weather. Freshly harvested seeds of most of these will germinate better after they are chilled a few days while moist at about 50 F.

The showing of two temperatures for vegetable seeds, as 68 -86 , represents a daily alternation of 16 hours at the first and 8 hours at the second. This alternation roughly simulates the change of night and day temperatures of the soil near the surface. Most species germinate faster and better under such alternating temperatures than under constant temperature. For the seeds of ornamentals the two temperatures indicate a favorable range but not a daily alternation. Exact optimum alternating temperatures have not been determined for these seeds as they have for "farm" and vegetable seeds.

Two figures are shown for the time for germination of vegetable seeds at the specified temperatures. The first figure is the time at which most good seeds in a sample that will germinate will have done so. Seeds that would not germinate at these temperatures by the second time interval are unlikely to have value for planting at the time of such a test. For the seeds of ornamentals, the two figures indicate the normal time within which most seedlings will appear above ground at the temperature shown, following proper planting.