October Gardening To-Do List

Design fall containers using a mix of annuals and perennials featuring bold autumn hues. This pot will shine through fall with a combination of gold and red calibrachoa, lime green Angelina sedum, ‘Plum Dazzled’ sedum and ‘Ogon’ variegated sweet flag (Acorus gramineus). All but the calibrachoa can slide into the perennial garden when their pot debut is over. Expect this mix of plants to bring the color through Thanksgiving in all but the coldest zones. In regions with mild winters, these plants will keep the show going all winter long.

The last fall feeding is the most important of the year for cool season turf, including Kentucky bluegrass, perennial ryegrass, fine fescue and tall fescue. In fact, if your lawn is healthy, it may be the only feeding you do all year. Typically it takes place after the last mowing. This fertilizer is often packaged as a “winterizer” product containing slow-release nitrogen and potassium, which helps promote strong root growth before the ground freezes. When to apply winterizer varies depending on where you live. Northern zones will start winterizing as early as late October, while warmer regions may wait until late November.

Dig and divide established perennials that have outgrown their spot in a planting bed or have a dead area in the center of the clump. A perennial that has stopped flowering is also a good candidate for division. Or maybe you just want to multiply a favorite plant. To divide, dig the entire perennial, discarding the oldest part of the clump. Replant the newer, younger portions of the clump, which are usually located along the edges. Immediately after planting, water divisions and continue to do so until the ground freezes if it’s a dry fall.

In some regions, autumn rains cover watering needs. In areas with freezing winters, it’s important to water trees and shrubs throughout the fall. If drought conditions persist before the ground freezes, continue to water, especially trees and shrubs that were planted in the last 12 months. Evergreens, including rhododendrons and Oregon grape, need to go into winter hydrated to prevent winter burn

Fall is an ideal time to plant trees. Roots continue to grow as long as the soil isn’t frozen. Choose potted or balled-and-burlapped trees, and be sure to set them into soil at the same depth they were growing before. Water plants as fall unfolds, especially if your region is in drought conditions or rainfall is scarce. Mulch soil after planting, taking care not to pile it directly against the tree trunk. Extend mulch a few inches beyond the tree’s dripline to help retain soil moisture in the root zone.

Cut back perennials that have gone to seed. For open-pollinated or heirloom plants, gather seeds for planting next year. For plants like black-eyed Susan (Rudbeckia, shown), purple coneflower (Echinacea) or joe-pye weed (Eutrochium), snip off whole flower heads and place them on screens to dry. Once the heads are dry, remove the seeds, working gently to separate seeds from the chaff. Store seeds in paper envelopes, not plastic bags. Label seeds immediately; don’t trust your memory. If you wind up with too many seeds, host a neighborhood seed swap this winter.

Add compost, composted manure or leaf mold to garlic beds before planting. Time planting for at least two weeks before your region’s first average fall frost date. If you miss that window, don’t worry. You can still tuck garlic into the soil up until a few weeks before the ground freezes. Maximize the amount of garlic you grow by planting bulbs in a staggered pattern. For the biggest bulbs, space cloves 6 to 8 inches apart. A bulb dibber creates planting holes quickly. Water after planting. If the ground freezes where you garden, mulch with 6 inches of straw or 4 inches of chopped leaves. For areas where the ground doesn’t freeze over winter, use a 2-inch-thick mulch layer.

As you start fall garden cleaning, don’t remove every single stem. Leave some annual and perennial seedheads in the garden for overwintering birds. They’ll feast on many species, including sunflower (shown), purple coneflower, zinnia, cosmos and aster. Ornamental grasses also provide beak-pleasing seeds. If you plan to hang bird feeders this winter, get them up by mid-October. Birds establish their winter feeding routines well before winter arrives.

October is the prime month for bulb planting in many zones. If you’re fed up with deer feasting on your tulips, focus your purchases on bulbs that wildlife tends to ignore. Great choices include Allium species, such as this giant type, which weaves a bit of whimsy into any garden. Giant allium varieties unfurl globes from a modest 4 inches to a whopping 10 inches across. The bulbs, leaves and flowers taste like onions, so critters leave them alone. Other good wildlife-resistant bulbs include daffodil, hyacinth, fritillaria and grape hyacinth. For smaller bulbs that wildlife ignores, try Anemone blanda, crocus, dwarf iris, Chionodoxa or Eranthis.

Start planting spring-flowering bulbs as soon as you see them for sale. Try something different with your bulbs this year to stage a spectacular spring show. Plant daffodils in large drifts along a fence or the edge of your yard. Daffodil flowers face the sun, so keep that in mind if you want to see the blossoms from indoors. Tuck crocus, snowdrops or Siberian squill into a lawn for naturalizing. Or plant a river of hyacinth edging a planting bed (shown). For the best show, buy the biggest bulbs you can afford. Toss any that have soft spots. If tulips are missing their papery covering, they’re fine to plant, as long as bulbs are firm.

In warm regions (Zones 6 and higher), plant salad greens for a fall crop. Leaf lettuce, spinach, radish and mustard greens will continue to grow until the ground freezes, filling your salad bowl for weeks to come. Add a frost blanket, and you can extend the harvest season by roughly a month. In colder zones, fall-planted lettuce can survive a warm October and, with the help of frost blankets, they will continue to yield well into November. Use a cold frame or unheated high tunnel, and you might harvest greens until Christmas. Fertilize crops of established greens that have been in the garden for three to four weeks.

Houseplants that have spent the summer outdoors often add substantial growth and may pick up insects. Before shifting plants inside for winter, trim stems as needed. For trailing plants like this vining violet (Viola hederacea), snip stems back to the bottom of the pot. Spray plants with insecticidal soap to help discourage any insects from hitchhiking indoors. If houseplants clearly have an infestation, spray plants every five days for three weeks, making sure to coat leaf undersides. Indoors, before moving plants, prepare saucers or cachepots and spaces to receive plants. Pull plant stands from storage and set them up. Clean windows and floors before plants limit access.

Fall is a great time to test soil so you can address any deficiencies before spring planting. DIY rapid soil test kits (shown) work well, but accuracy can vary by brand. For a thorough soil analysis, pick up a soil test kit through your local extension office. The beauty of a fall soil test is that you have ample time to act on the results and add the right amendments to the soil so it’s good to go for spring planting.

If the grass is growing, keep mowing. Gather grass clippings and fallen leaves with a grass catcher bag to add that material to your compost pile or to use as mulch in the garden. Lower the mower as the season unfolds. Shorter grass allows blowing autumn leaves to keep moving; longer grass blades catch leaves. Ticks remain active as long as air temperature stays above freezing, so it’s important to keep grassy areas mowed.

Cleaning up the perennial garden in the fall is a hot topic of debate among gardeners. Some embrace a clear-cut method, creating a clean slate for easy spring mulching. Others eschew any autumn cleaning, leaving every stem. A hybrid approach can help spread the work over several seasons while leaving stems behind for winter interest or providing ripe seedheads for hungry birds. If you do opt for cutting stems, wait until after a killing frost, and leave 6-inch stem stubs. These stems will catch leaves that can help insulate perennial crowns over winter.

Thanksgiving and Christmas cacti form flower buds in response to day length and/or cool air (55° to 65° F). Plants grown outdoors for summer on a porch or shady deck will set buds naturally as fall days start to shorten. For plants kept indoors year-round, cover plants at night or slip them into a dark closet to provide 14 to 16 hours of darkness daily for one week. (Set a notification on your phone to help you remember to cover plants at night.) Do this approximately six to eight weeks before you want plants to bloom. Holiday cacti can remain outdoors until night temperatures stay in the low 40s.

When purchasing fall squash, pumpkins and gourds, choose ones that don’t have blemishes or cuts — they’ll stay fresher longer. For outdoor displays, place a flat rock beneath pumpkins, gourds and decorative squash to prevent direct contact with soil. This helps limit insect activity and slow the rotting process by keeping moisture away. If you’re displaying these fall fruits on wooden surfaces — indoors or out — protect the wood by placing fruits on something non-porous, like a glass plate or plastic saucer.

Enjoy fall’s crisp afternoons by dealing with leaves often. Leaves that accumulate on grass can kill it. Left on decks and sidewalks, leaves create slippery footing. Try to rake and remove leaves as soon as possible after the major fall drop occurs. Time leaf raking or mowing before rain mats leaves together. If you don’t want to rake, mow over leaves with a mulching blade, chopping them into fine bits that can work their way between grass blades to soil.

Detach hoses, remove debris and drain rain barrels before cold weather arrives. Clean the rain barrel using detergent and a long-handled brush to scrub the inside. Rinse well. In mild-winter zones where winter brings rain, leave valves open to prevent damage from ice. In zones where winter brings snowy, severe cold, remove the hose and screen, placing them in a garage or shed. Store the rain barrel upside down or covered for winter to prevent water from freezing, expanding and cracking the barrel. Don’t forget to attach a temporary extension to your downspout so stormwater is directed away from your home.

Before night temperatures drop to freezing, remove all hose-end attachments, including watering wands and nozzles. Detach hoses from hose bibs, and close any interior shut-off valves along exterior water supply lines. To drain an irrigation system, turn off the main water source, then systematically open each valve to release water and air pressure in the line. Keep valves open for a few minutes. In coldest zones, if irrigation lines aren’t buried at least 12 inches deep, you’ll need an air compressor to blow water out of the system.

The original, old-fashioned butterfly bush (Buddleja davidii) is considered invasive in many states. If you happen to have one on your property, cut plants back by at least half in the fall, with the goal of removing all seedheads. Apply this same principle of clipping seedheads on any plant that tends to self-sow aggressively in your garden, such as boltonia, coneflower (Echinacea), black-eyed Susan (Rudbeckia), dame’s rocket (Hesperis) or joe-pye weed (Eutrochium).

Monitor weather reports daily as temperatures start to nosedive. When frost is in the forecast, protect plants by covering them with a sheet, towel or other non-plastic material. Wait to remove covers in the morning until the air has warmed. Often the frostiest time of day is through the morning hours. To keep the vegetable garden yielding through frosty nights, cover plants with frost blankets made from spun polyester. The blanket lets sunlight and water through but excludes frost. Frost blankets come in different thicknesses or weights to protect plants in various temperatures. Read labels carefully to get the protection you need.

Cool-weather weeds like henbit and dandelion take off in autumn’s lower temperatures. Prevent weed growth by putting pre-emergent herbicide in your planting beds. For lawns of warm-season turf, including Bermuda, zoysia and centipede grass, apply a pre-emergent herbicide. Don’t use a pre-emergent if you’re planning to seed or overseed your lawn.

Pot up bulbs for forcing into bloom to infuse spring color into wintry days. To flower successfully, bulbs need a cold period — typically 14 to 16 weeks at 41°F to 48°F, although it varies by bulb type. When the cold period is complete, bulbs need another two or three weeks at room temperature before the flower show begins. Plant bulbs for forcing now, and you’ll have beautiful blooms by January. Good candidates include crocus (shown), tulip, hyacinth and daffodil.

Reseed bare spots in cool season lawns of Kentucky bluegrass, perennial ryegrass, fine fescue and tall fescue. Fall overseeding helps repair thin lawns, like those beneath trees with high canopies or worn by foot traffic. Mark areas you overseed so you know where to water after seeding. With cool-season grass, if you plan to aerate, do so before overseeding. To keep dormant warm-season lawns of Bermuda, zoysia, St. Augustine or centipede grass green through winter, overseed with annual ryegrass.

After frost damages foliage, dig bulbs, tubers and corms of non-winter hardy plants, including dahlia, calla lily, canna, caladium, gladiolus and tuberous begonia. Clip the remaining stems, leaving a short stub attached to the bulb. Dry bulbs in the sun or a shed for several days, until soil falls away. Gently knock or rub soil from bulbs, shorten stems and store in sawdust or peat moss in a cool, dry place for winter. In the warmest regions, bulbs don’t need to be lifted. Just clip plants back after frost to remove dead leaves, and mulch roots well for winter.

Covering soil has always been viewed as a key to soil health, but new research shows that you can improve soil even more by keeping it planted. Cover crops provide the answer. In winter, use annual ryegrass and crimson clover in unplanted areas as a cover crop. Turn the crop under in spring before letting flowers set seed. Plant a living mulch, such as dwarf clover, as a cover crop under tall vegetables, like broccoli and cauliflower.

Fall is an ideal time for planting — and transplanting — shrubs. Cool air reduces water loss through leaves, and autumn rains help fuel strong root growth. Visit garden centers, nurseries and local gardens to discover shrubs that offer stunning fall color, like this dwarf fothergilla (Fothergilla gardenii), which grows 2 to 3 feet tall and wide. Leaves on this native shrub showcase a kaleidoscope of autumn hues, including gold, red, purple and orange. Fothergilla is hardy in Zones 5-8, with varieties available that grow up to 8 feet tall and wide.

Tropical hibiscus need to come indoors this month if you plan to save plants for next year. Prune by removing up to one-third of the plant, either by cutting specific branches to soil level or pruning the entire plant to reduce height and spread. Tropical hibiscus have shiny green leaves and are typically grown in pots outdoors. Perennial or hardy hibiscus like this Perfect Storm (shown) are hardy in Zones 4 to 9, with plants dying back to the ground after a hard freeze. These hibiscus are dormant underground through winter and sprout in late spring. Hardy hibiscus stems are tough, fibrous and stand up to heavy snow. Leave them in place through winter for added interest, or cut them back to 4 inches.

Keep potted fuchsia indoors for winter, and you can enjoy the same plant next spring and summer. Before moving fuchsia indoors, trim green growth by half, removing flowers, buds and fruits along with green shoots. Plan to place plants in a cool room (50s or 60s) with a window. Lay a sheet beneath the plants to catch dropping blooms and fruits. This not only makes clean-up easier but also protects floors or carpet from pollen, fruit or petal stains. Water plants just enough to keep roots alive, not to fuel new growth.

Whether tucked into containers or added to planting beds, pansies bring color all autumn long in most regions. In warmer zones, they’ll keep the flowers coming throughout winter. In northern regions, buy the largest pansy transplants you can find. Use tighter plant spacing because growth will be slow in cooler temperatures. To create a full look in a container, plant pansies closer. Ideal temperatures for flower development are nights in the 40s and days in the 60s.

If you’re growing pumpkins to store for winter, do not let them experience frost. Ideally, harvest pumpkins and any other winter squash before frost is in the forecast. If your area experiences an early cold snap that lasts just one night, cover ripening pumpkins with a sheet, bucket or box. When it’s time to harvest, cut pumpkins and winter squash leaving a 1- to 2-inch stem attached to fruit. Don’t use the stem as a handle, or you risk breaking it. That stem helps to seal the pumpkin, enabling it to store longer.

Older pine needles drop from trees in fall. This pine straw provides an attractive mulch that’s traditionally placed around azaleas, rhododendrons and camellias in the South. Pine needles also make a terrific mulch for muddy footpaths, breaking down slowly. Or simply rake needles to create an eye-catching mulch beneath pine trees. But in areas prone to wildfires, gather needles and any cones and dispose of them.

Many plant sellers want to reduce inventory they have to overwinter, which means you can score some real steals on perennials. Look for bargains at box stores, garden centers, feed co-ops — anywhere that sells plants. Some perennials traditionally planted in fall include peony and bearded iris, but you can also tuck a host of other perennials into soil safely in fall and expect a show next year. Plants including bee balm (shown), coreopsis, garden phlox and coneflower will all transition well with an autumn planting. Coralbells often experience frost heave over winter, where soil freezing and thawing actually pushes plants out of the soil. In colder zones, you might want to add those to the garden in spring. For best success, get perennials in the ground no less than six weeks before the ground freezes.

Take cuttings of plants that aren’t hardy enough to survive winter. Many plants root easily in water, including plectranthus (shown), pineapple sage (Salvia elegans), Mexican bush sage (Salvia leucantha), coleus, begonia and polka dot plant (Hypoestes). Herbs that root well in water include mint, lemon balm, oregano and basil. Take cuttings from non-woody stems that are 3 to 4 inches long, removing all leaves that would fall below the water line. Place jars in a sunny spot, and watch for roots. Transplant rooted cuttings when roots are roughly 2 inches long, tucking into small pots filled with potting mix.

In general, you want to avoid pruning woody plants — trees and shrubs — in fall. Shorter days and tumbling temperatures signal these plants to prepare for winter dormancy. Pruning triggers new growth, which incoming freezes will definitely kill. But there are exceptions to fall pruning. It’s okay to remove dead branches, which might come down during winter ice storms. It’s also a good idea to shape or remove storm-damaged branches, which would likely protect a tree from further damage.

Stop procrastinating starting a compost pile. Fall leaves, spent or frozen annuals and kitchen scraps provide an ideal foundation. You don’t even have to invest in a fancy bin. A circle of fence wire creates a pile with ample airflow. One secret to success with a compost pile is to place it where it’s readily accessible for adding material and also handy to garden areas where you’ll use the finished compost.

As plants succumb to frost, watch for deer damage on remaining green plants, including ones they may have ignored all summer long. This hydrangea shows tell-tale signs of deer damage: torn leaves and stems. Deer lack upper front teeth, so they bite and yank their heads upward to tear off parts of plants. Protect shrubs that retain leaves into early winter by covering with bird netting held in place with clothespins. Plan to use deer repellent sprays in late fall to keep deer at bay. Good choices include Plantskyyd, Deer Defeat and Bobbex.

After clearing summer crops from the vegetable garden, plan to cover the soil for fall and winter. Layering on compost and chopped autumn leaves is a great practice. Another option is to compost in place by piling frost-killed annuals and emptying annual-filled container gardens onto planting areas. Cover the materials with chopped fall leaves, add some finished compost and cover the whole mound with straw. By spring, much of the material will have broken down. Toss things that haven’t broken down completely into the compost pile.