Garden, Local Harvest
Spring ahead this fall: Now’s the time to transplant perennials and direct-sow flower and herb seeds
The summer of 2020 was a scorcher in the Salt Lake Valley. We melted a number of previous records, with the hottest August in 143 years. As the weather finally cools with the change of the season, there’s much to be done in the garden.
We recently covered planting cool weather vegetables in the garden. It’s also an ideal time for transplanting perennials as well as planting many flowers and herbs from seed.
These direct-seeded flowers and herbs are not intended to germinate now, but rather to be in position to germinate next spring.
From a design perspective, planting in the fall is a serious boss move.
Take a look around your garden, and you’ll see where you have bare spots that could use more plantings, or also make accurate judgments of the heights of plants at their maturity. This allows for much better design as opposed to making these calls in the spring, when much of your garden is just hidden potential.
Fall really is the ideal time for planting perennials. As garden centers mark down their inventory to clear things out before winter, the thrifty gardener can save oodles of loot purchasing plants in fall rather than waiting until spring.
In addition, fall-transplanted perennials can take advantage of warm soil temperatures. This allows the roots to grow much more quickly than in the spring, when soil temperatures are cooler. Plants that establish themselves in the fall are able to blast off in the spring, resulting in a larger plant with more blooms.
Fall in Utah is also much more stable, from a plant’s perspective, as opposed to the wild ride of fluctuating temperatures in spring. By getting a head start, fall planted perennials can become fully established before the heat of next summer sets in, and will require much less water and pampering than those planted in spring.
The boss move is to get perennials planted at least six weeks before the ground freezes solid. It’s anyone’s guess when that will happen exactly, but transplanting by the end of October is a safe bet. Plants that aren’t established before that time can be subject to “frost heave,” where the plant is lifted and pushed out of the ground by the action of the freeze/thaw cycle.
Make sure to mulch generously around fall-planted perennials when the nights begin to regularly see temperatures at 32 degrees and below.
However, don’t mulch before that, as the boss move is to take advantage of as much soil warmth from the sun as possible.
Perennials that are a must-have in my garden and form the backbone of many of the hedgerows at my farm are Blue Queen salvia, purple coneflower, yarrow, rabbitbrush, Russian sage, goldenrod, Mexican milkweed, hyssop, and globe thistle.
Direct seeding in the fall is a next level boss maneuver. That’s how nature do, literally dumping seeds onto the soil to overwinter.
In fact, many plants require a repeated freeze/thaw cycle to break down the seed coat, a process known as vernalization. While this process can be simulated by bringing seeds in and out of the freezer for a spring planting, that is simply too much work. Let nature do her thing.
Some plants that respond well to fall plantings are native wildflower mixes, penstemon, echinacea, wild columbine, black-eyed Susan, northern sweetvetch, sweet alyssum, ammi and sky blue aster.
Fall-seeded plants get growing much earlier than spring-seeded plants, and on average you’ll see blooms two weeks earlier. Having a plethora of early blooms in the garden is a surefire way to attract pollinators and predatory insects, the latter of which are likely to take up permanent residence for the season when you extend them the right invitation.
It’s also much easier to find a beautiful day for planting in the fall, which means you’ll get it done on time. Chaotic weather in spring means you’ll often get delayed waiting for that perfect day.
The process is straightforward, and the only challenge is in keeping your actions minimal and not overworking your planting. The goal is to mimic how nature seeds.
- Wait until the first hard frost kills back sensitive plants.
- Prepare your planting area by removing any existing weeds or unwanted plants.
- Rake the area clean, then lightly roughen up and cultivate the surface using a hard metal rake.
- Sprinkle your seeds on the surface according to the directions on the seed packet.
- Compress the seeds into the seed bed, by gently walking over the area or patting them with the back side of a flat-nose shovel.
- Mark and label the seeded area. Otherwise, come March, you will have forgotten all about your fall-seeded patch and may very well start planting something else there. A boss gardener always labels and dates a planting!
- Last, and most important, stop! Do not cover the seeds, do not apply mulch or straw, simply leave them as is.
The weather and the seasonal shifts to take their course, and next spring you’ll be greeted by a fresh stand of sweet l’il plant babies.
James Loomis is a full-time urban farmer, educator and keeper of the Old Cherry Orchard (aka OchO), a permaculture farm. He lives in Salt Lake City.