There’s one certain day when the light changes in the garden—it’s lower, streaming through the trees as the day fades away. Summer is giving way to fall.

Although for some gardeners it might seem like a time to relax, harvesting warm red tomatoes and enjoying burgeoning hanging baskets in their prime, this is one of the most important times for planting.

This is the time to add cool weather crops in the vegetable garden along with perennial flowers, shrubs, trees and spring bulbs. As the tomatoes and peppers reach their peak, another planting of lettuce is called for, which could persist well into early winter. It’s one crop that not only survives in cool weather, but thrives in mild temperatures.

Lettuce is a perfect choice for containers, too. Fresh plants are available at local nurseries along with packets of seeds. Black Seeded Simpson is one of the most popular leaf lettuces, but there are a wonderful variety of cultivars like pretty looking Freckles, Red Sails and the curiously named Flashy Trout Back.

The September garden has room for lots of other vegetables. Radishes love cool weather and are a perfect crop to plant with kids or grandkids, as the seeds sprout quickly and the radishes will be ready in a month or so. Other leafy greens like Swiss chard, arugula, mizuna, mustard greens, kale and others will enjoy a late summer planting.

In our climate, spinach grows best when planted in the fall. It’s a frustrating spring crop: As soon as things warm up, even for a few days, spinach plants “bolt,” or go to seed. Plant now and you can harvest spinach through the fall. It’s the perfect crop to winter over with protection.

One season extender to make that happen is a floating row cover: a spun bound translucent fabric that acts as a greenhouse. Floating row covers are so lightweight that the plants alone can hold them up, although wire hoops will help keep the plants from being flattened by deep, wet snow.

A cold frame is simply an outdoor unheated greenhouse with a hinged top that’s either clear or translucent. It’s another tool to help the fall plantings along. To get the most out of a cold frame, set it up facing south and angle the lid at 35 degrees.

Besides extending the season in the vegetable garden, this is the time to plant bulbs for spring blooms. Bulb planting can be a lot of work with a payoff that happens months away, but once a gardener is hooked, planting every fall becomes a tradition filled with anticipation for the spring to come.

For each bulb, dig a hole three times as deep as the bulb’s size. The easiest way to get them in the ground is to use something called a bulb auger. It’s just a big drill bit that fits on a power drill, making planting fun and easy. My favorite is the Power Planter 3-by-7-inch tool. It’s only around $25 and can be passed down to the next gardening generation.

Some unique deer-resistant bulbs include snowdrops, glory of the snow, winter aconite, allium, hyacinths and daffodils. For tulip lovers, keep in mind that they are deer candy and would need to have a physical barrier or be sprayed religiously with a deer repellent to survive.

Daffodils are the true harbingers of spring. Daffodils are not just yellow trumpets; there are 13 different divisions or types of flowers. They are best planted in informal drifts, not as rows of soldiers. To extend the bloom time, plant early, mid-season and later-flowering varieties to have color from late March into May.

In a happy accident last season, I planted leftover daffodil bulbs during winter thaws in February. I wasn’t sure if they would even bloom, but they eventually flowered after all the other daffodils were finished. I’m going to continue to experiment with this this season.

The reason trees and shrubs are planted right now is that the day length and temperatures are conducive to root growth as opposed to top growth.

They can be planted successfully in the spring, but the plant will be putting on growth and, in some cases, trying to flower along with establishing a root system too, and that’s a lot to ask from any plant.

For fall-planted trees and shrubs, it’s all about the right plant in the right place. Figure out how big they will get at maturity, but remember, plants like that don’t stop growing, just slow down at a certain point. Also, it’s important to know if the plants want sun, shade and what kind of soil will make them happy.

When choosing a tree or shrub, think of how many seasons of interest the plant provides beauty. A tree like stewartia has a beautiful shape, peony-like flowers, nice fall color and exfoliating bark that looks good all winter. Wolf Eyes kousa dogwood foliage is variegated, blooming with star-shaped white flowers followed by bright red marble-sized seed pods.

Most gardeners begin their planting journey with annuals that last from frost to frost, but then begin to incorporate perennials over the years and they come back on their own. For the most part, perennials only bloom for a few weeks as opposed to annuals, which bloom all summer long. What many perennials lack in long bloom times, they make up in ease of maintenance, beautiful foliage and the fact they don’t need to be replanted every season. As with trees and bulbs, the fall climate is perfect to get them established.

A favorite perennial and one I write about endlessly is called corydalis lutea. It blooms with pretty yellow flowers from April until early winter, is deer-resistant and will tolerate anything from dry shade to full sun. Corydalis lutea will make a nice colony in a couple of years by throwing seeds, not with invasive underground runners. It’s the perfect plant for containers too, due to its long bloom time.

Speaking of containers, this is also time to plant pansies. These beautiful, colorful flowers love cool weather and can persist until Christmas or beyond. If the annuals in pots are starting to look tired, get a flat of pansies and/or violas to spruce up the container. They also go well with flowering kale, which will thrive well into winter. As the season gets colder, the flowering kale gets prettier. There are short varieties in white, red and pink along with one called Redbor which is more treelike. It’s wonderful to have color after frost takes the annuals.

Don’t pass up an opportunity to plant in the fall; it will extend the life of this season’s garden and also your landscape for many years to come.