The proper time to seed sweet clover should be determined by the
germination of the seed, the climatic conditions of the region, and
the condition of the seed bed at the time of sowing. When growing
under natural conditions, seed which has lain in the ground over
winter germinates in sufficient quantity during the following spring
to produce a stand. It is therefore assumed that since this seed has
passed the winter on or in the ground and has produced a good stand
the following spring, sweet clover may be sown at any time of the year
and a satisfactory stand obtained. Little is thought of the enormous
number of seeds which shatter from a single plant and fall on an area
not exceeding 5 or 6 feet in diameter. Single plants have produced as
many as 350,000 seeds (the approximate number in 1½ pounds), or about
10,000 seeds for each square foot of ground covered. It matters little
how many of these seeds germinate in the fall they mature or during the
following winter, when the seedlings will be killed by freezing, for
there will be enough viable seeds left in the ground to germinate when
conditions are favorable in the spring. Conditions are very different
when sweet clover is sown on cultivated soil at the rate of 5 to 20
pounds of seed to the acre--25 to 100 seeds to the square foot. When
this quantity is sown, it is necessary that it be planted at such a
time that the greatest number of seeds will germinate and produce
plants.