September starts the gardening year in the greenhouse. Plants are brought in from outdoors, seeds of annuals are sown for winter and spring greenhouse flowers, winter-flowering bulbs are potted and started into growth, cuttings are inserted for next summer’s outdoor plants, and seedlings started during the summer are ready for transplanting or potting.
The month is often tricky in its extremes of temperature. September can overheat a greenhouse in a few minutes, causing automatic ventilators to operate frequently. If your greenhouse is not ventilated automatically, it is wise to check the temperature often during sunny hours and provide ventilation manually.
Ventilation is especially important in areas where September is hot, muggy, and sultry’ with the little natural movement of air, as in many coastal areas. This is a month of newness and beginnings in the greenhouse, and most young plants need plenty of light and air to grow successfully.
If crowded together, they will grow spindly, and diseases and pests will flourish.
Discard Plants, Not in Good Shape
health, unless you have space to spare for an isolated clinic. Night heat may be needed at times during September, both for warmth and to lower excess humidity. On the other hand, extreme heat in September, clay or night, can be dangerous to cool-house plants.
The tender plants which have been growing outdoors during the summer need to be lifted and transferred to the greenhouse before even a hint of frost. These include chrysanthemums, winter-flowering buddleias, stevias, Christmas cherries, and peppers.
Hydrangeas that have grown outdoors all summer, in pots or nursery beds, are potted early in September, placed in a close cold frame or greenhouse for about a week, and gradually given more light and air until they get as much as possible to ripen the wood before the plant goes dormant.
Then they are stored in a cool location (cellar or protected cold frame) until forcing time. Tie and disbud chrysanthemums and carnations; fertilize lightly.
Indoor Plants For the House
The house plants which have summered outdoors come inside in September, and it is best to bring them in full two weeks before the heating system goes into operation, so they can gradually acclimate themselves to a drier condition than they have had all summer.
Examine all house plants minutely for insects and signs of disease. Eradicate the trouble or discard the plant.
Sponge the foliage to remove dust and grime, or better yet, wash the plants with a stream or spray of water that reaches all parts, including the underside of the leaves, using care not to break the foliage. Try to place each plant in an indoor location that will give it the light, temperature, and humidity it requires for best growth.
44659 by Elaine Cherry