For some strange reason, spring planting of lawn seed has become a custom, yet in nature, not a single species of grass used for this purpose ripens seed during that season.
To make spring planting possible, the seed is artificially stored over winter and planted when conditions are unfavorable for best growth.
In the wild, grass seed ripens in early summer but does not fall to the soil before sometime in August. About then, fall rains occur, and moisture causes the seed to sprout.
Lawns seeded between August 15 and September 15 are much more likely to succeed than at any other period during the year.
There are several reasons why this is true. For one thing, temperatures are highly favorable. Blue grasses, in particular, sprout best when nights are cool and days warm, a condition more likely to prevail in August than at any other time of the year.
The optimum temperature range is 90° degrees Fahrenheit on days and 50° degrees Fahrenheit on nights.
Moisture Conditions Are More Favorable
As the sun sinks farther and farther to the south and days grow shorter, water loss by evaporation is reduced.
Even if fall rains do not occur (as is sometimes the case), artificial watering is more effective, and less water is needed.
Weed competition is much reduced in late summer and early fall. Last year’s seeds of annual weeds have sprouted as a rule, and this year’s crop has not yet ripened.
As a result, grass seedlings can grow rapidly and take advantage of moisture, food, air, and light without competing with weeds.
Quality Of Light
Another favorable factor is the quality of light that falls on the lawn. Sunlight is strong in the red end of the spectrum and is known to produce stronger root growth than when it is strong in blue.
As the sun sinks lower and lower to the south, it passes through denser air filled with more dust particles than it does earlier in summer.
The dense air and dust combine to screen out the blue light but allow red rays to come through. As a result, seedlings that appear in early fall produce a bigger root system than those that sprout in spring.
Equally important, soft top growth is retarded, producing a tougher, more cold-resistant plant, better surviving its first winter.
Preference Given To Fall Sowing
These are the reasons why preference should be given to fall sowing if a choice is possible.
The period for best results here in the Midwest —August 15 to September 15—is quite short, but this does not mean that seeds cannot be sown after September 15.
However, each day after that date means about a 5% loss in chances of success. By October 1, chances of a good stand are so slim that seeding is inadvisable.
Despite the favorable conditions prevailing from August 15 to September 15, the same precautions should be taken when sowing at other seasons—preparing a good seed bed, soaking blue grass seed overnight to speed germination, and sowing on the surface so seed is not buried.
If the soil is dry, remember to water.
44659 by R. Milton Carleton