September Pointers… Tips for the Northern Gardeners

The first damaging frost sometimes arrives during September, in and around New York City it may occur as early as the second or third week of the month, and those of us who live in valleys may be surprised by a frost even earlier than that.

Gardening Pointers for SeptemberPin

My neighbor whose place is on the hill above me, not much more than a city block away, almost every year has flowers weeks after I do.

Storage Protection For Plants

There are numerous jobs of protection to be done before those first frosts arrive.

House plants that were plunged outdoors should be brought inside or put into a cold frame and protected with sash and mats for a few weeks longer.

The standards, such as lantana, fuchsia, and heliotrope that you wish to sieve for another year, should be put into tubs or pots and stored in an airy root cellar or the greenhouse.

The root cellar is preferable since it provides darkness and moisture and allows the plants to ripen with less shock to the plants.

If they are stored in the greenhouse, shade them till they dry off and then show signs of growth.

Heavy heads of standards should be sheared to half their size when the plants are lifted. During the period of drying off, hold water to a minimum.

I prefer not to hold over the standards of fuchsia and heliotrope and instead start new plants from cuttings each year.

Begonias and geraniums must be lifted before frost, as must all tender plants if you plan to save them.

Or if you want cuttings of them, be sure to take them before frost strikes the plants outdoors.

All tender tub plants such as hydrangea, gardenia, and summer flowering oleander should go into storage late this month.

A cool, enclosed porch is excellent for storing these evergreen plants, and they are at the same time decorative.

Bulbs, corms, and tubers of gladiolus are lifted within the next six weeks and dried off before removing the tops, and dahlias should be lifted as soon as frost blackens the tops.

They all require a Frostproof, cool, dry, airy storage place.

Soil Conditioning

Do not forget to sow winter rye to be turned under next spring as space becomes vacant in the garden, and also plan to do some double digging.

Double digging seems to be an easier job in the fall than in the spring, perhaps because the weather is cooler and time is moving plentiful.

If you do not plan to either double dig or plant winter rye, do, however, clean up the garden thoroughly and dig it over, leaving it in as rough a condition as possible so that winter snow and frost can penetrate and benefit the soil.

Fall Bulb Planting

You can start this month to plant narcissus and numerous small bulbs such as grape hyacinth, crocus, snowdrop, scilla, and chionodoxa.

It is not difficult to plant large numbers of these bulbs where a mass effect is planned if the grass is first cut very short and a system of planting is used.

Try using string for guides and mark off a strip about 18” inches wide, and then within this area punch the soil full of holes 12” inches deep and 3” or 4” inches apart.

Have at hand a quantity of screened soil to which a 6”-inch potful of bone meal has been added to each bushel of soil.

Here’s what you need to do:

  • Fill the holes with this soil mixture to within 2” or 3” inches of the surface and then tamp it in with a stick to make sure all pockets are filled.
  • Drop a bulb in each hole, right side up (it will be 3” or 4” inches from the top), and fill the remainder of the hole with soil, packing it level full.
  • Complete the job by marking off as many additional strips as you require.
  • If only a few scattered bulbs are to be planted, a trowel will no doubt be handier.

Peonies that are too large or are not flowering, or for some other reason must be moved, are best shifted this month.

Divide the clumps into pieces with 5 or 6 “fingers” and replant the pieces in prepared soil.

Peonies, like roses, are rank feeders and should have a bone meal and manure in their soil, or rotted compost can be substituted for the manure.

I like to prepare holes for peonies just as for roses, but do not plant the eyes or tops of the roots any deeper than two inches; and as with roses, plant firmly.

Iris And Daylilies

September is a good time to start dividing the clumps of iris and daylilies. Split them into good planting clumps, discarding the centers.

Enrich the soil before replanting by digging and incorporating humus, compost, or manure.

Perennial Border

Every five or six years perennial borders should be completely pulled apart and then replanted after the soil has been properly prepared.

Next month the work of remaking the border should start, but in the meantime, frost may make it difficult to identify the plants.

Therefore, if you plan to do the job this year, label all the plants as to color, height, and whether you want a lot or only a few of each variety. Do the labeling this month.

Rhubarb And Asparagus

If you have manure available, mulch the rhubarb and asparagus beds. This mulch is dug under in the spring and the plants are greatly benefited from it.


You can extend your vegetable season somewhat by picking the green tomatoes and peppers before the arrival of Jack Frost and storing them on a shelf in the cellar or flats in a cold frame.

With sash protection over the frame, they will continue to ripen for about six weeks.

Winter-keeping types of squash, such as Winter Queen and Hubbard, can be stored in a cool dry cellar for a considerable time.


Remove old canes now from raspberry bushes so that the young ones will have as much space as possible and more air. The next crop of the fruit comes in on the new wood.

Maintaining Temperatures In The Greenhouse

Fluctuating night temperatures are disastrous to most greenhouse plants, so as soon as it is possible to control them by all means do so.

Cool crops such as chrysanthemums, stocks, snapdragons, carnations, and many others like a night temperature of 50° to 52° degrees Fahrenheit, while 60° to 62° degrees Fahrenheit is a good average temperature for such crops as roses and poinsettias and stove or tropical plants.

Watch the day temperatures also. They should not be allowed to run more than 10° degrees Fahrenheit warmer than the night temperature on dull days, and not more than 15° degrees Fahrenheit warmer on bright days.

Of course, in sunny fall weather, this is not always possible, but heat can be shut off during the day, and ventilators are used to control the warmth inside.

In cold weather watch the wind and ventilate from one side of the house only to prevent drafts. Drafts cause mildew.

Remedy And Control For Red Spider

Sodium selenate is an excellent control for the red spider. Apply it to benches and pots as per the manufacturer’s directions for red spiders, aphids, and other insects.

Soil that has been treated with sodium selenate is poisonous for three or four years.

Plants absorb the poison, so when you discard it from the greenhouse be very certain it is NOT dumped where vegetables are likely to be grown.

Use it for a top dressing for your lawn. Use similar discretion when discarding treated greenhouse plants.

Potting Bulbs For Indoor Growing

Pot up bulbs for indoor growing this month. If the freesias were not put in last month, you can still do so, following the same procedure suggested in last month’s Pointers.

Narcissus, tulips, hyacinths, and bulbous iris should all be potted now, or as soon as you receive them.

Pot them in bulb pans with the bulbs touching each other and allow the nose of the bulb to stick out of the soil.

The bulb pans should be placed in a trend 12” inches deep, in a deep cold frame that is frostproof, or in a cool cellar that stays around 35°.

If buried in the trench outdoors, put a half-inch of sand over the pans before covering them with soil.

This will simplify the job of separating the soil of the pots from the soil of the trench when you dig them up.

In the cold frame, they should be covered with about 9” inches of either rotted leaves or coal ashes.

In the cool cellar, darkness is all they require. Bulbs must be potted and buried in this manner to make them root before forcing starts.

And no matter which way the bulbs are handled, they must be watered thoroughly before covering. 

Lily bulbs for forcing can be rooted either under the bench or on top of the bench if a little hay is put over them.