While winter is often considered a slow time in the garden, there are still several things that can be done from December through February to prepare for spring and keep yourself active in the garden even when there is snow on the ground!
General Tasks | Perennials | Vegetable Gardens | Annuals | Trees & Shrubs | Lawns | Indoor Plants | More Information
General Winter Tasks
Clean & Repair Tools & Equipment
Proper care of garden tools and equipment prolongs their lifetime, prevents costly repairs, and improves their performance. Remove caked-on soil from shovels, spades, hoes, and rakes with a wire brush or stiff putty knife. Wash the tools with a strong stream of water, then dry. Sharpen the blades of hoes, shovels, and spades. Wipe the metal surfaces with an oily rag or spray with WD-40. Sand rough wooden handles, then wipe with linseed oil to prevent drying and cracking. Hang or store the tools in a dry location.
Be sure to drain water from garden hoses and bring them inside to prevent damage from freezing. To prevent kinking, store hoses on reels or coil them and place them on a flat surface.
Wheelbarrows, carts, and wagons may also need some attention before spring arrives. Clean them thoroughly and touch up paint chips with spray paint to prevent exposed steel from rusting. Grease wheels to prevent squeaking.
Sprayers used for insect, disease, and weed control should be thoroughly washed and rinsed. Most pesticides recommend triple rinsing. This includes all parts of the sprayer from the holding tank to the nozzles. Tip the sprayer upside down or hang it upside down when not in use so that it can drain and dry thoroughly. Fertilizer spreaders should be washed thoroughly as well. Store any pesticides, fertilizers, and other chemicals in areas that stay above 40°F to prevent freezing which can cause containers to break and leak.
Disinfect Tools & Containers
Winter is a great time to clean and disinfect plant containers. Late winter and early spring is when many new seedlings are started and potted up so being ready with clean containers is beneficial. Reusing plastic, clay, and other containers is a great way to save money and reduce the amount of plastic waste. Cleaning and disinfecting pots each time you use them is important since disease-causing fungi and other organisms, including insects, can remain in and on old containers, infecting the new plants potted in them. Learn more in this article: How to Clean and Disinfect Plant Containers.
Proper cleaning and sanitization of pruners, loppers, saws, and other garden tools is important to prevent the spread of diseases. If you haven't been cleaning them throughout the growing season, winter is a great time to sanitize so you can start the growing season healthy. There are several methods that can be used. Find the best method for you in this article: How do I sanitize my pruners to prevent the spread of disease?
Feed the Birds
Providing food for birds over the winter is a nice way to add life to the winter landscape. Food is especially important during periods of harsh winter weather. Additionally, make sure the birds have access to water. Bird feeders, birdseed, suet, bird bath heaters, heated bird baths, and other supplies are available at many garden centers, farm stores, and other retailers. Learn more in this article: Let's Take the Birds to Lunch from the Iowa Ornithologists' Union.
Visit An Indoor Garden
A vacation in Florida, Arizona, or other warm-weather location is a great way to beat the winter blues. If a vacation isn't possible, don't despair. It's still possible to enjoy a tropical reprieve by visiting an indoor garden. Iowa boasts several beautiful public gardens that can be enjoyed any day of the year, even in winter. You can access a listing of public gardens across the state in this article: Public Gardens of Iowa. Visit the one closest to you and check each of them off your list as you travel the state.
Plan for the Upcoming Gardening Season
Winter is a great time to dream and plan for the next growing season. Leaf through seed catalogs and browse mail-order nursery websites to find the must-have plants for this spring. Survey the garden throughout the winter months to see what has been damaged and needs to be repaired or replaced. With this information, you can plan what and when you can start hardscape projects or new garden beds.
If a new landscape is in the future, winter is a wonderful time to start planning. Functional and beautiful landscapes start with thorough planning. Utilize this worksheet to help you analyze, design, and outline a complete landscape design plan: Home Landscape Planning Worksheet: 12 Steps to a Functional Design.
Perennials
Inspect Perennials for Frost Heaving
The warming and cooling of the upper layer of soil throughout the winter can cause plants to frost heave, which can lead to excessive drying and death of the plant. Newly planted perennials with small or underdeveloped root systems are more prone to frost heaving, as are certain shallow-rooted perennials like coral bells. On warm winter days with no snow cover, inspect newly planted or heave-prone perennials and lightly tamp them back down into the soil to be sure any exposed roots are covered.
Check on Tender Perennials & Other Overwintering Plants
The tubers, corms, and bulbs of tender perennials like cannas and dahlias can easily dry out over the winter months. Check on these bulbs regularly throughout the winter to make sure they are not drying out and to remove any that show signs of rot. Learn more here: How to Overwinter Tender Perennials.
Newly planted perennials should be monitored as well over winter. Temperature fluctuations, underdeveloped root systems, and dry or wet soil conditions can all cause issues for these plants. Learn more in this article: How to Overwinter Plants
Unplanted perennials being overwintered in a nursery bed or unheated structure should be checked on periodically all winter. Soil moisture must be monitored carefully in this situation. Check moisture levels of the soil often during the winter and irrigate if necessary. When the soil is frozen, supplemental irrigation is not necessary. In an unheated structure, water may be needed as often as once every two to three weeks if temperatures are above freezing. Avoid over-watering plants. Learn more in this article: Overwintering Unplanted Trees, Shrubs and Perennials
Use Cut Trees as Mulch
There are several ways you can recycle or reuse your cut Christmas tree after the holidays. Prune off the tree’s branches and place the boughs over perennials as a winter mulch.
The cut tree can also be placed in the yard or garden for use by birds and other wildlife. The branches provide shelter from strong winds and cold. Food can be supplied by hanging fruit slices, seed cakes, suet bags, or strings of cranberries or raisins on the tree’s branches. You can also smear peanut butter and seeds on pine cones and hang them in the tree. Once spring arrives, chip the tree and use the chipped material as mulch in perennial flower beds.
Consider Starting Some Perennials from Seed
While most gardeners prefer to grow perennials from transplants in containers, it is possible to grow some perennials successfully from seed. Several perennials have cold treatments (stratification) or other requirements for successful germination and most will take several years to become large enough to flower in the perennial border. Winter is a great time to start the seeds indoors or to provide the necessary cold treatment so they are ready to germinate outdoors in the spring. Research the growing requirements for the perennial to understand what special germination requirements are needed to grow them from seed.
Perennials grown from seed will be similar to the parent plant but may differ in flower color, leaf pattern, size, or in other ways. For some perennials, this is problematic because there is a very specific size, color, or leaf pattern you may want. Growing perennials like daylily, hosta, or peony from divisions or transplants ensures they are clones and identical to the parent plant. For other perennials, there is little variation from plant to plant when grown from seed, or the variation is something that is desirable. These perennials are perfect candidates for seed propagation. Perennials to try growing from seed include columbine, purple coneflower, and blackberry lily. Get a more complete list here: What perennials are easy to grow from seed?
Enjoy the Beauty of Perennials with Winter Interest
It can be difficult to see the beauty of winter some times. While woody trees and shrubs are often thought of as plants with beautiful winter attributes, many perennials can also add to the garden even in the dead of winter. Take time to appreciate the beauty of your perennials in the snow. Learn more in this article: Perennials with Winter Interest.
Vegetable Gardens
Plan Garden Layout
A well-planned vegetable garden ensures productive and healthy plants. Use the winter months to determine what vegetables you want to grow and where you will plant them. Crop rotation is important as it can reduce issues with diseases and pests and balance the soil's nutrients. Vegetable crops in the same botanical family are often susceptible to the same diseases and insects. For crop rotation to be most effective, gardeners should not plant vegetables belonging to the same plant family in the same location for 3 to 4 years (or 5+ years, if possible). Learn more in this article: Crop Rotation in the Vegetable Garden.
Order Seed from Catalogs & Websites
Winter is an ideal time to plan and select what vegetables and varieties you will grow in the coming year. Leaf through seed catalogs and browse mail-order nursery websites to find the must-have plants for this spring. Research varieites and cultivars to find those that meet your needs making sure to not only consider taste, size, and color, but also things like disease resistance. Popular vegetables will sell out early so shopping early allows you to have the best selection. Consult this publication to find some of the best vegetables for your garden: Suggested Vegetable Varieties for the Home Garden.
Gather Seed Starting Supplies
If you intend to start vegetable seedlings indoors, make sure that you have seeds, a germination medium, containers, and other supplies on hand. Seeds can be purchased at local garden centers or from mail-order companies. Commercially prepared soilless mixes, such as Jiffy Mix, are excellent seed-starting media. The germination medium should be lightweight, porous, and free of pathogens. Many different types of containers can be used for germinating and growing transplants, including flats, trays, cell packs, pots, cut-off milk cartons, or paper cups, among other things. Most often, the best quality transplants are produced by providing supplemental light. Gather fixtures and other equipment to provide the best light for the young plants. Learn more in this article: Guide to Starting Seed Indoors.
Test Germination Rates of Stored Seed
If you plan to grow from seed purchased one or two years ago, it is beneficial to test the germination rate to be sure they are viable and worth the time to sow and grow. The germination rate of seed will go down the longer it is stored. If germination rates are low, you will benefit from sowing more seed to ensure that enough seedlings germinate and grow to have the number of plants you need for your garden. When germination rates are exceptionally low, discarding the old seed and buying fresh seed packaged for that growing season is often more productive. Learn more in this article: How to Store Seeds and Test Germination Rates.
Start Seedlings of Cool Season Crops
Many vegetables started from seed indoors only need 6 weeks to reach a size that transplants well into the vegetable garden after the danger of frost has passed. In Iowa, the typical frost-free date is the first or second week of May. Six weeks before this date is in early spring (mid-March).
However, many vegetables can be planted outdoors before the frost-free date including cool-season crops like broccoli, cauliflower, cabbage, kale, kohlrabi, and onions. These vegetables can be planted outdoors in early to mid-April, meaning they need to be planted indoors in late February or early March.
More information on planting dates for vegetables can be found in this article: Vegetable Planting and Harvesting Times.
Annuals
Decorate with Natural Materials
Evergreen boughs, ornamental seed heads, decorative branches, and other materials can be arranged in annual beds, frost-proof containers, and window boxes to create interest all winter. Empty and store those containers that are not frost-proof to prevent cracking over winter.
Gather Seed Starting Supplies
If you intend to start flower seedlings indoors, make sure that you have seeds, a germination medium, containers, and other supplies on hand. In most cases, the highest quality transplants are produced by providing supplemental light. Gather fixtures and other equipment to provide the best conditions for growing young plants.
Check Seed Viability
If you plan to grow from seed purchased in a previous growing season, it is beneficial to test the germination rate to be sure they are viable and worth the time to sow and grow. Seed left in storage will decrease in quality over time and the germination rate will go down the longer it is stored. Learn more in this article: How to Store Seeds and Test Germination Rates.
Order Seed
Winter is an ideal time to plan and select the annuals you wish to grow in containers or flower beds in the coming year. Browse seed catalogs and mail-order nursery websites to find the must-have plants for this spring. Popular flowers will sell out early so shopping early allows you to have the best selection. Good sources for seeds can be found in this article: What are some good sources of flower and vegetable seeds?
Start (Some) Seed Indoors
While many annual flowers only need to be started indoors 6 to 8 weeks before transplanting outside, some require more time. Several annuals require 10 or more weeks indoors before transplanting outside meaning they must be sown indoors in mid to late February (if not earlier). These include annuals such as geranium (Pelargonium), impatiens (Impatiens), petunia (Petunia), Begonia (Begonia), Lisianthus (Eustoma grandiflora), Periwinkle (Catharanthus), Polka Dot Plant (Hypoestes phyllostachys), and Dusty Miller (Senecio), among others. Learn more about the indoor sowing date for various annuals in this article: Germination Requirements for Annuals and Vegetables.
Cool-season annuals, such as snapdragon, pansy, and sweet alyssum, are great additions to the garden in early spring. Many are tolerant of a light frost often surviving down to 28°F or sometimes even 25°F with little damage to flowers or leaves. They can be planted in much of Iowa in April and sometimes as early as late March, depending on the weather. These annuals need to be sown indoors during winter to be ready to go outside in early spring. This means that the indoor sowing date for many of these species is mid-January to early February (6 to 8 weeks before transplanting outside).
Learn more in this article: Guide to Starting Seed Indoors.
Trees and Shrubs
Prune
Late Winter/early spring is the ideal time to prune nearly all woody plants. The focus of pruning should be on removing damaged, diseased, or dead material first. Then, remove rubbing, crossing, and structurally deficient branches (like double leaders). Finally, remove those branches that improve appearance.
Learn more about all things pruning, including tips, timing, tools, and techniques, in this article: Your Complete Guide to Pruning Trees and Shrubs.
Monitor for Animal Damage
Rabbits, mice, voles, and deer can cause considerable damage to trees and shrubs, especially those that have been recently planted. Young trees and shrubs benefit from protection over the winter. Even if protective wrappings or fencing have been installed, check on woody plants regularly throughout the winter, looking for signs of animal damage such as stripped bark or missing foliage and stems. If damage is observed, install additional physical barriers to prevent further damage. There is nothing that can be done in winter to fix the damage, but if caught early many trees and shrubs can recover from minimal damage. Learn more in this article: How to Protect Trees and Shrubs from Animal Damage Over Winter.
Remove Heavy Snow, Leave Ice Alone
Heavy snow and ice on the branches of trees and shrubs can cause considerable damage. Improper removal of ice and snow can increase the amount of damage to trees and shrubs.
When heavy, wet snow accumulates on evergreens, gently shake the snow from the branches or carefully brush off the snow with a broom by sweeping upward. Never brush downward as you risk breaking already bent and stressed branches.
Ice storms can cause considerable damage. Don't attempt to remove the ice by beating the branches with a broom or rake. This will only cause greater damage. In many cases, it is best to leave the tree alone and hope for a quick warm-up. Ice-laden trees can also be propped up until the ice layer melts.
Learn more in this article: How to Prevent Ice and Snow Damage on Trees and Shrubs.
Tap Maple Trees for Syrup
Late winter is the typical time to collect sap from sugar maple for the production of maple syrup. Trees must be ten or more inches in diameter and sap collection usually begins in Iowa in late February or early March and lasts for approximately three weeks. The process of collecting sap and producing maple syrup requires some specialized equipment and advanced planning. Learn more in this article: Maple Syrup Production.
Force Flower Branches Indoors
You can brighten up the last few weeks of winter by forcing branches of flowering trees and shrubs indoors. Forsythias, pussywillows, serviceberries, crabapples, magnolias, redbuds, and many fruit trees can be coaxed into early bloom indoors, adding some bright color and helping revive the spirits of winter-weary gardeners. Learn more in this article: How to Force Branches of Spring-Flowering Trees and Shrubs.
Avoid Salt Damage
Trees and shrubs, especially evergreens, planted near heavily salted roads and walkways can experience damage if not protected. Salts affect plant growth in several ways causing dehydration and negatively affecting soil quality.
Minimize salt damage to trees and shrubs by avoiding the use of deicing salts or only applying as much as needed to melt ice and only in areas where it is needed. To reduce salt usage but maintain safe conditions, mix salt with abrasive materials, such as sand or kitty litter. Avoid piling salt-laden snow and ice around trees and shrubs. While the amount of salt applied to major roadways can not be controlled, steps can be taken to minimize damage. As soon as the ground thaws in early spring, heavily water areas where salt accumulates over winter to flush out excess salt from the root zone.
Learn more in this article: Using Deicing Salts in the Home Landscape.
Continue to Water Recently Planted Trees & Shrubs
Any woody plant planted within the last growing season, especially those planted in early fall, needs supplemental water when soil conditions are dry. Check soil moisture frequently - both the original root ball and the surrounding soil - and water deeply when either (or both) is dry. Monitor soil moisture conditions and water when needed until the ground freezes. Some years, this can be much later into winter than you would expect, but on average, it is sometime between mid-November and early December across much of Iowa. Once conditions warm in late winter (usually around mid-March in Iowa), resume monitoring.
Lawns
Remove Leaves
If winter winds blow in a lot of leaf debris from trees that are late to shed leaves, like oak, it is important to remove them. Excessive leaf debris on the lawn will mat down, blocking light and preventing gas exchange, causing turf areas to die. Learn more in this article: Do I need to remove the leaves on my lawn?
Avoid Excessive Salt Buildup
Lawns along heavily salted driveways and sidewalks or in areas where snow from these areas is piled up can see excessive amounts of salt accumulate in the soil or on the grass leaves. Salts affect plant growth in several ways causing dehydration and negatively affecting soil quality.
Minimize salt damage by not piling salt-laden snow from driveways or sidewalks on the lawn. Wait until the precipitation has ended before applying salt to walkways and only apply as much salt as needed to melt ice and only in areas where it is needed. If possible, do not use deicing salts at all. To reduce salt usage but maintain safe conditions, mix salt with abrasive materials, such as sand or kitty litter.
Learn more in this article: Using Deicing Salts in the Home Landscape.
Watch for Snow Mold and Other Damage from Pests
Extended snow cover on ground that is not completely frozen is conducive to turf diseases called snow mold. Symptoms of snow molds first appear when snow melts in late winter or early spring. Circular, straw-colored patches appear in the lawn as the snow recedes. Patches may be a few inches to a few feet in diameter. These patches may continue to enlarge if the grass remains cool and wet. Damage caused by snow mold usually is not serious, and affected areas typically green up eventually, though more slowly than the rest of the lawn. Raking the affected areas gently can help to dry them out and prevent further fungal growth. Learn more in this article: Snow Mold.
The meadow vole is a small, brown, mouse-like animal. Though common in Iowa, the meadow vole is secretive and seldom seen by most individuals. Voles feed on grasses and other herbaceous plants. Vole damage typically occurs to the lawn and becomes apparent when the snow melts. Several narrow, meandering pathways appear on the lawn. Meadow voles usually don’t cause serious harm to lawns. Damaged areas usually recover on their own within a few weeks. Learn more here: Voles: Damage Management.
Avoid Walking on the Lawn While the Ground is Frozen
When frozen (and even after a frost), turfgrasses are susceptible to damage to leaves and growing points, especially if an area is repeatedly walked on, for example, by the dog or while taking a shortcut to the mailbox. Damage from foot or vehicle traffic during the growing season can be quickly recovered from because plants are actively growing. But damage during the winter cannot grow and repair itself until spring and repeated traffic can cause considerable damage. Additionally, walking or driving on partially frozen or wet soils can lead to compaction, which will impact growth in the future.
Maintain Mower and Other Power Equipment
Winter is a good time to service the mower to ensure the mower runs smoothly and cleanly cuts the lawn. Start by checking the oil. Some mowers benefit from changing the oil once a year. Others only require the oil to be topped off in the spring. Check your owner's manual and follow those instructions to check or change the oil. Check all filters, including the air, oil, and fuel filters, and clean or replace them as needed. Ideally, the fuel tank was drained or ran dry in the fall, but if it wasn't, it is important to remove the old fuel and replace it with new before starting up the mower for the first time in the spring. Check and replace the spark plug every one to three years. A fresh spark plug will allow the engine to run better and start-up easier.
Take the opportunity to sharpen the blades and clean the mower deck while the fuel tank is empty. Dull mower blades make the engine work harder and tear or rip grass blades rather than cleanly slicing them. The ragged edge of a grass leaf cut with a dull mower blade will turn brown and allow some disease pathogens to infect the leaf more easily. To remove the blade, wear heavy leather gloves, disconnect the spark plug (or remove the battery on an electric mower), and jam in a short 2x4 to keep the blade from turning. Loosen the bolt at the center of the blade using a socket wrench. It may take some leverage to get it loose! Once removed, you can sharpen the blades yourself or take them to a hardware store or outdoor equipment retailer for sharpening. While the blade is out, this is also the perfect time to clean the mower deck. Use a strong stream of water and a putty knife to remove built-up debris from the underside of the deck and wash or blow leaves and grass from all the other areas of the mower.
Similar maintenance should be done on any power equipment with a small gasoline engine, including weed trimmers, blowers, and tillers. Two-cycle engines, or engines that run with a gas and oil mixture, should have the oil-gas mixture removed for the winter. Run the engine with the choke open to remove fuel from the lines. Check the spark plug and replace it if it is worn. Replace other worn or damaged parts as well.
Indoor Plants
Protect Plants from Cold Temperatures
Keep indoor plants away from drafts such as the warm draft from a heat register or the cool draft from the front door opening in winter. Avoid trapping plants between the curtain and windowpane where temperatures in the sun of the day can get very warm and then quite cold in the middle of the night.
Always take special care to protect houseplants from cold outdoor temperatures while transporting them from the store to your home. Purchase houseplants at the end of the shopping trip and get the plant as quickly as possible to a heated vehicle. Always transport the houseplant in a plant sleeve or carefully wrap it before going outdoors. Most garden centers and greenhouses will wrap the plant for you, but many grocery or big box stores do not. You may have to request a bag or sleeve to wrap the plant yourself. Exposure to freezing temperatures, even briefly, may cause damage such as wilting, browning, or leaf drop and can kill the plant in extreme situations.
Monitor Frequently for Insect Pests
Common houseplant pests like scale, mealybug, aphids, spider mites, fungus gnats, and whiteflies can be problematic over the winter months. Their populations can seem to explode in a matter of weeks. For this reason, it is important to monitor for pests frequently and deal with them as soon as they are noticed while populations are small. When managing any houseplant pest, often the best results come when you pair multiple techniques simultaneously. Learn more in this article: Diagnosing Houseplant Problems Caused by Insect Pests.
Raise Humidity Levels
Most indoor plants are from tropical areas and grow best in high humidity (40 to 50%). Most of our homes have very low relative humidity levels, especially in the winter (as low as 10%). This low humidity can lead to slow growth, dried-up flower buds, and brown leaf tips and edges. Increasing the humidity, especially in the winter months, can encourage healthier growth and better-looking plants.
There are several ways to raise humidity for indoor plants. One of the easiest ways to raise humidity is to group plants together. Other options include using a humidifier, pebble tray, or terrarium. Misting does not raise humidity levels for more than a few minutes, making it an impractical and ineffective way to raise humidity. Learn more in this article: How to Care for Houseplants.
Change Watering and Fertilizing Habits
Light for indoor plants is lower in winter due to shorter days and the lower angle and intensity of the sun. The lower light levels, along with the lower temperatures and humidity we see indoors in the winter, mean houseplants are growing less. With less growth comes less need for fertilizer. Reduce fertilization frequency during the winter months. The change in light, humidity, temperature, and growth rate also means that watering needs may change. Check plants regularly, but only water when the soil is dry to the touch. Learn more in this article: How to Care for Houseplants.
Provide Supplemental Light (If Needed)
While most indoor plants are well suited for low-light environments, sometimes the light levels in winter become too low. Houseplants that are not receiving enough light develop spindly growth, leaf drop, yellowing foliage, excessive stretching or elongation, and lack flowers (if there should be flowers). Plants not receiving adequate light should be moved to brighter locations. If these conditions cannot be found, then supplemental light may be needed. Learn more about the factors to consider when providing supplemental light and how to set up supplemental light systems in this article: Growing Indoor Plants Under Supplemental Lights.
