Fall equinox will occur on September 22 and this signals the official start of autumn … but for gardeners, fall has already begun. You can feel it by the slowing of plant growth, the first blooms on fall-flowering plants … and there are even trees that starting to change color. It’s not the cold nights that cause these reactions in plants, but rather the shortening days. There are fewer hours of sunlight and the plants see this as a signal to start preparing for winter.
ACTIONS TO TAKE
The onset of fall also signals to gardeners a series of actions they must or can take to make the most of the season.
- Bring in houseplants that spent the summer outdoors. Not only don’t they tolerate the cold nights that will soon arrive, but they reacclimatize more readily to indoor conditions if they are brought in early.
- Thoroughly rinse indoor plants with a good stream of water before bringing them indoors. That will knock off any insects that may be hiding there. Also, spray with an insecticidal soap solution.
- Repot houseplants that have outgrown their pot size during their summer outdoors.
- Watch for the arrival of spring-flowering bulbs in stores. Buy them as soon as they arrive, because not only does the choice decrease rapidly, but storage conditions in most stores are harmful to the bulbs and they’ll soon begin to dry out.
- Plant certain spring-flowering bulbs without delay. Most bulbs can be stored in a cool, dark place until as late as October, if you want, but some small bulbs dry out quickly, notably winter aconites, anemones and fawn lilies (trout lilies). Therefore, you should plant those without delay.
- Plant fall-flowering bulbs. You also have to plant colchicums and autumn-blooming crocuses early, as soon as they arrive in local stores; otherwise they’ll bloom in their bag!
Perennials, Trees and Shrubs
- You can divide or transplant most garden plants at this time of year. The big exceptions are fall-flowering plants, which are still actively growing, and slow-growing plants, especially those of limited hardiness, such as many rhododendrons. Wait until spring to divide or transplant these.
- Stop fertilizing. It isn’t wise to fertilize hardy plants (trees, shrubs, evergreens, perennials, etc.) in fall, because late fertilization can stimulate new growth that will not have time to harden off with the onset of winter. It will therefore be subject to winter damage.
- Be ready to harvest cold-sensitive vegetables (tomatoes, peppers, eggplants/aubergines, beans) as soon as the first frost is announced. They can also be covered with a “tent” (of floating row cover, old sheets, plastic sheeting) to protect them if the cold isn’t expected to last more the 24 hours.
- Lay sod or sow grass seed. You can also topdress and oversow a weak lawn to thicken it up. You’ll have much more success repairing lawns in the fall than in the spring.
And there you go: a few minor jobs you can carry out now, or at least soon, so that your garden remains beautiful throughout fall and into next year. Nothing too strenuous for a laidback gardener, of course! Just a few things you might want to try when you have a couple of minutes of free time and feel like interacting with your plants!