Nifty 50

September means seventh month, from the Latin septem for seven. It was the seventh month under the old Latin calendar. The Romans started their year in March. Under our Gregorian calendar it is of course the ninth month. September marks the astronomical end of summer and the beginning of fall with the autumnal equinox (equal nights). This year the equinox falls on the 23rd and coincidentally it will bring a full moon, the Harvest Moon.

Do you remember Jimmy Durante (or maybe “Old Blue Eyes?) singing the September Song from the musical Knickerbocker Holiday? Probably not, but you will remember the lines, “But the days grow short, When you reach September.” The days have been growing shorter since the Summer solstice but by now they are really shrinking fast. If you think these days are short, wait until December!

With the shorter days, and the lower angle of the sun, the days and nights are also growing cooler. For plants the magic number is 50. Fifty degrees is the temperature below which most vegetative growth stops. Most seeds need at least 50 degrees to germinate. Because of the cooler temperatures the soil also retains moisture longer. All of this adds up to making September and the fall the best time to plant shrubs and trees and the best time to start a new lawn. That’s why 50 is nifty.

Of course temperature can be either the warmth of the air, or the warmth of the soil. The temperature of the air can change quickly, the temperature of the soil not so fast. Tender plants can be killed by a hard frost. Half-hardy plants can be killed by a freeze (28 degrees for more than 4 hours). Trees and shrubs and perennials are not normally killed by a freeze unless it is sustained below their normal temperature zone.

For them soil temperature is the key. Root growth continues while the soil temperature is around fifty degrees even if the air temperature is below freezing. What appears to be dormancy above ground doesn’t apply underground. When you plant trees and shrubs in the fall their roots continue to grow. Some winters around here the soil temperature in the root zones never freezes. It is not unusual for the roots to continue to grow through January.

For grass, the seed will germinate as long as nighttime temperatures don’t go much below 50 degrees. Remember the soil temperature doesn’t change as quickly as the air. Sowing grass seed in prepared soil, mulching with seed free straw (cover about half the bare ground) water regularly and you can establish a fabulous lawn. This works for bare areas also. Don’t mow until the grass is established at about 4 inches height and then mow down to 3 inches.

For newly planted trees and shrubs water well and frequently until the ground freezes. This is true of all trees and shrubs if we have a dry fall. Evergreens especially should be watered generously until freeze-up. With their foliage (needles) remaining on during the winter they are susceptible to drying out.

Some people dig the holes for planting now so they’ll be ready to plant the moment they bring the plants home.

Things to do in the garden:

Planting spring flowering bulbs, irises and peonies this fall takes advantage of the warm earth and gives them time to establish themselves before winter and be ready for spring. A good rule of thumb is to plant bulbs at a depth about three times the height of the bulb.

Irises and peonies should be planted about 2 inches in depth. If your peonies haven’t bloomed well because of shade from nearby competing trees, now is a good time to move them to a sunnier place in the yard.

Watch for yellowing of gladiolus leaves. Dig the corms and hang until the tops turn brown. Then store in a cool, not freezing, well ventilated basement or garage. Do the same with caladium, cannas, and dahlias when their tops turn brown.

Fall is a good time to divide Lily of the valley, primroses, peonies, day lilies, coral-bells and bleeding heart. Adding bulb food and humus will be rewarded in the spring.

Now is a good time to test your soil. The called for amendments will have time to work their way into the soil and be available to the plants for the next growing season. Information on soil testing is available at the OSU Extension Office 474-7534.

As you empty your vegetable rows or beds add organic matter. It can break down over the winter. Any chores you can do now to get ready for spring is a good idea. The weather is usually better in the fall than in the spring.

It’s not too late to start beets, carrots, kale and lettuce, maybe even bush beans! If you have row covers, or can make them, you can have these for Thanksgiving dinner. Of course this assume we don’t have a hard freeze and if we do you are prepared to cover the plants if it happens. If the ground temperature stays above 50 it will be nifty.