When the gardening season starts winding down, it can feel like planting season is over. In reality, fall is the beginning of next year’s garden for several types of plants.
In Ontario, fall is the traditional planting season for many spring flowering bulbs and garlic. It can also be an excellent time to sow certain wildflowers, particularly species whose seeds benefit from exposure to cold, moist winter conditions.
The key is knowing what can actually be planted in fall, when to plant it, where it should go, why winter can be beneficial, and how to plant it correctly.
What Can You Plant in Fall?
Not everything should go into the ground before winter, but several important groups are well suited to fall planting.
Spring flowering bulbs include tulips, daffodils, crocuses, hyacinths, snowdrops, alliums, muscari and other hardy bulbs. These are planted in fall and flower the following spring. Many require a period of cold temperatures as part of their natural growth cycle.
Garlic is another classic fall planting choice in Ontario. It is planted as individual cloves in fall, remains in the ground over winter and resumes active growth in spring before being harvested the following summer.
Certain wildflowers can also be fall sown. However, this does not mean that every packet of wildflower seed should automatically be planted in fall. Always check the directions for the particular species or seed mixture.
Why Plant Spring Flowering Bulbs in Fall?
Tulips, daffodils, crocuses, hyacinths and many other spring flowering bulbs are naturally adapted to experience winter before they begin their spring growth.
The cold period helps satisfy the bulbs’ dormancy requirements. As temperatures rise in spring, the bulbs use energy stored inside them to begin producing roots, foliage and flowers.
That is why bulbs sold for fall planting should not be confused with tender bulbs and tubers such as dahlias, which are normally planted in spring in Ontario.
Planting the correct type at the correct time is important.
When Should You Plant Spring Bulbs?
In Ontario, hardy spring flowering bulbs are generally planted during fall while the soil can still be worked.
Landscape Ontario recommends planting spring flowering bulbs approximately six weeks before the ground is expected to freeze, when nighttime temperatures are around 5°C to 10°C. Some hardy bulbs can still be planted later as long as the ground has not frozen solid.
You do not want to plant so early that unusually warm conditions encourage excessive growth before winter.
You also do not want to wait until the ground is frozen and impossible to prepare properly.
Where Should You Plant Spring Bulbs?
The correct location depends on the particular bulb.
Many popular spring bulbs perform well in sunny locations with well drained soil, although light requirements differ among species.
Drainage is particularly important because bulbs sitting in persistently waterlogged soil are more susceptible to rot.
Before planting, consider what the area will look like in spring rather than what it looks like in fall. Deciduous trees, for example, may not have leaves when early spring bulbs emerge, meaning an area that becomes shady later in the season can receive considerably more sunlight in early spring.
Always check the requirements for the specific bulb you are planting.
How Do You Plant Spring Bulbs?
Start with healthy bulbs that feel firm rather than soft, badly damaged or rotten.
Prepare loose, well drained soil and plant each bulb at the depth recommended on its package. Planting depths vary by species and bulb size.
A commonly used general guideline is approximately three times the diameter of the bulb, but the package instructions should take priority. Landscape Ontario, for example, lists tulips at approximately 12 to 18 centimetres deep, while smaller crocuses are generally planted around 5 to 7.5 centimetres deep.
For bulbs with an obvious pointed end, place the point upward.
Cover them with soil and water after planting to settle the soil around the bulbs.
What About Garlic?
Garlic is one of the most useful edible crops to plant in fall.
Ontario grows garlic as a winter annual. The cloves are planted in fall, establish roots before winter and then resume vigorous growth in spring. The crop is harvested the following summer.
Garlic also benefits from exposure to cold. Many cultivars require vernalization, meaning exposure to sufficiently cold temperatures, to support proper bulb and clove development.
When Should You Plant Garlic?
Ontario guidance lists the garlic planting period beginning in September and extending into late October, although the appropriate timing varies with location and seasonal conditions. Growers generally aim to plant shortly before the average first fall frost so roots can establish before winter without producing excessive above ground growth.
Planting too early can result in shoots emerging before winter, increasing the risk of winter injury.
Planting too late may not provide enough time for adequate root development before the ground freezes.
For Ottawa gardeners, this means watching the weather and soil conditions rather than relying on one exact calendar date every year.
How Do You Plant Garlic?
Start with healthy garlic intended for planting.
Keep the bulb intact until shortly before planting because separated cloves deteriorate more quickly than whole bulbs.
Separate the bulb into individual cloves and plant them with the pointed end facing upward. Ontario production guidance recommends approximately 7 to 12 centimetres between plants, depending on the garlic variety.
Garlic performs best in fertile soil with good organic matter and adequate drainage.
In Eastern Ontario, winter mulching is commonly used. A layer of clean straw can help moderate soil temperatures and protect garlic roots and shoots from temperature fluctuations. Ontario guidance notes that straw is commonly applied approximately 10 to 15 centimetres deep.
What About Wildflower Seeds?
Fall sowing can work very well for certain wildflowers, but this is one area where it is important not to generalize.
Different wildflower species have different germination requirements.
Some native species have seed dormancy mechanisms that prevent immediate germination. Exposure to a period of cold and moisture can help overcome dormancy. This process is called cold moist stratification.
When appropriate species are sown outdoors in fall, winter can provide those changing temperatures and moist conditions naturally.
For example, an Ontario Invasive Plant Council native wildflower mixture containing wild bergamot, black eyed Susan and evening primrose specifically recommends fall sowing, with germination beginning in spring.
Why Do Some Wildflower Seeds Need Winter?
In nature, many native plants release their seeds during late summer or fall.
Those seeds may spend the winter outdoors before germinating when favourable conditions return.
For species requiring cold moist stratification, this winter period can help break physiological dormancy and prepare the seed for germination.
However, not every wildflower requires the same treatment. Some seeds need different lengths of cold exposure, while others may not require stratification at all.
This is why you should always follow the planting instructions for the particular species or wildflower mixture you purchase.
Where Should You Plant Wildflowers?
The location should match the species contained in your seed mixture.
A mix designed for full sun should not be planted in deep shade simply because there is an empty space available.
Before sowing, check the sunlight, soil moisture and drainage of the area.
Site preparation is also important. Wildflower seed needs contact with the soil. Scattering seed over a thick lawn, heavy mulch or dense weeds is unlikely to produce the same results as sowing onto a properly prepared site.
For the Ontario native wildflower mixture referenced above, the recommended method is to begin with a weed free site in full sun, distribute the seed evenly, lightly rake it and then press the seed into contact with the soil.
Who Should Consider Fall Planting?
Fall planting is a great option for gardeners who want more spring colour, want to grow their own garlic, or want to establish appropriate wildflowers for the following growing season.
It is also useful for gardeners who want to spread their workload throughout the year rather than leaving every planting job until spring.
You do not need a huge garden.
Spring bulbs can be planted in garden beds and borders. Garlic can be grown in a dedicated vegetable bed or other suitable garden space. Wildflowers can be used to establish an appropriate patch or garden area where their growing requirements can be met.
How Should You Prepare the Soil?
Preparation depends on what you are planting.
For spring bulbs, focus on loose, well drained soil.
For garlic, choose fertile soil with adequate organic matter and good drainage.
For wildflowers, removing competing vegetation and creating good seed to soil contact is often more important than heavily enriching the soil.
Do not automatically add large quantities of fertilizer to every fall planting. Soil fertility requirements vary by plant, and unnecessary nutrients will not guarantee better spring growth.
Should You Mulch After Planting?
Mulch can be useful, but the amount and purpose depend on the crop.
For spring flowering bulbs, a modest layer of mulch can help moderate soil temperatures and retain moisture. Landscape Ontario suggests approximately 5 centimetres over bulb beds.
Garlic in Eastern Ontario is commonly given a substantially deeper layer of clean straw for winter protection.
Wildflower seed is different. Do not bury a newly seeded wildflower area beneath a thick layer of conventional mulch unless the instructions for your particular mixture specifically recommend it. Small seeds need appropriate contact with the soil and suitable conditions for germination.
What Should You Avoid Planting in Fall?
One of the biggest mistakes is assuming that anything called a bulb should be planted in fall.
Tender summer flowering bulbs and tubers such as dahlias are generally planted in spring rather than left outdoors through an Ontario winter.
You should also avoid assuming that every wildflower seed requires cold stratification.
Always identify what you are planting and follow the specific directions for that plant or seed mixture.
Common Fall Planting Mistakes
Planting spring bulbs in poorly drained soil can lead to rot.
Planting garlic too early can encourage excessive shoot growth before winter, while planting too late can limit root establishment.
Planting bulbs upside down or at an inappropriate depth can affect their performance.
Scattering wildflower seed directly over existing turf or thick mulch can prevent adequate seed to soil contact.
Another common mistake is expecting everything planted in fall to appear immediately. Fall planting is largely about preparation. Much of the activity is happening underground or within dormant seeds while you wait for spring.
A beautiful spring garden can begin months before the snow melts.
Fall is the time to plant many spring flowering bulbs such as tulips, daffodils and crocuses. It is also the recommended planting season for garlic in Ontario and can be an excellent time to sow certain wildflowers whose germination benefits from natural winter conditions.
The important part is choosing plants intended for fall planting and giving each one the conditions it actually requires.
Choose the right location, prepare the soil, follow the recommended planting depth and timing, and then allow winter to do its part.
When warmer weather returns, the work you put into your garden this fall can be one of the first things you see growing next spring.
Start Next Spring’s Garden at Ritchie Feed & Seed
Get a head start on next year's garden with fall planting essentials from Ritchie Feed & Seed. https://www.ritchiefeed.com/
