By Marianne Lepa, Master Gardener in Training, SCMG
Fall is a great time to get your garden ready for spring. In fact, you can even think of the next gardening year starting after October 1st. What do you in fall can have a significant effect on how next year’s garden performs.
First and foremost, rid your garden of any diseased plants or debris. Bacteria, fungi and viruses overwinter in dead plant material and seeds. Disease can travel in heavy rain, with melting snow, or be picked up by foraging animals and carried to other parts of the garden. A gardener should always be vigilant to disease by removing infected plants right away, but especially so in fall.
Be sure to also collect any fallen leaves or flowers and contaminated mulch. If your municipality has a separate organic waste pickup and they heat treat compost, then diseased material can be sent out with the municipal organic waste. (Hint: if your organic waste collection allows pet waste, then your municipality does use a high heat to decompose compost.) If you aren’t sure if your municipality heat treats compost, enclose diseased plant material in a plastic bag and send to the landfill. If you can, burn the material instead.
If your herbaceous plants are not diseased, consider leaving them standing all winter to provide food and habitat for overwintering pollinators and beneficial insects. Fruits and seed heads are appreciated by winter birds. Hollow stems can be burrowed into and provide a safe spot for overwintering insects and dead foliage left on the ground makes a warm blanket for someone.
If you don’t want to leave plants standing, cut them at soil level and chop them. You can leave them right on the soil to break down over winter or add it to your compost bin. Leave the roots in the soil to break down over winter and provide food for beneficial bacteria and fungi.
Dig up and store tender tubers and bulbs, such as gladiolas and dahlias. Before putting them away in a dry cool place, like the basement, root cellar or attached garage, check them over and discard any that are damaged or soft. Keep only the best to prevent fungus and rot from spreading through the collection over winter.
Plant garlic and spring flowering bulbs in fall. They need the cold to break dormancy. Bulbs provide early colour in the garden and fill empty spots that can be later used for annual flowers.
Lightly prune and shape perennials that bloom on new wood, such as hydrangeas and roses. They will begin to grow as soon as the weather warms and shaping them now will give you the best display of flowers.
Normally done in spring, amending your soil can be done in fall. It may actually be the better time since adding manure, compost and organic fertilizers will have time to break down and build the biological activity of the soil. Give your beds a light rake, add your compost and amendments. You don’t need to dig them in, the action of freeze-thaw and snow melt will incorporate them for you.
Winter can be hard on structural plants that don’t die back to the ground. Wind and extreme cold can dry out evergreens and since the ground is frozen, they’re unable to take up water to replace what is lost. A midwinter thaw can fool a tree into breaking dormancy too early and repeated freeze and thaw cycles can cause shrubs to heave out of the ground. Tree bark is also a source of food in winter to animals such as mice, rabbits and deer. Take steps now to prepare your shrubs and trees for winter.
Mulch young plants with 3-4 inches of straw or wood chips past the root zone, but be sure to not put mulch directly around the trunk. Leave a few inches of air space to prevent rot. Wrap the trunk with plastic or wire guards to keep chewing animals away. Young deciduous trees should have their bark wrapped or painted with a diluted white interior latex to protect them from winter sunscald or cracking when the bark is heated in the sun and then rapidly cooled after dark. Young evergreens need their needles protected from excessive evaporation with windbreaks or shrub wraps. You can help your evergreens by keeping them very well watered until the ground is frozen. If your shrubs are near a road, a barrier will protect them from sprayed road salt.
Herbaceous plants that do die back to the ground still need protection from freeze/thaw cycles and warm spells in late winter. A layer of straw or compost will prevent the soil from thawing too quickly and protect the soil from erosion and harsh sunlight. Compost spread in fall will continue to feed the soil’s microbiome until the ground freezes and pick right up again after it thaws in spring.
Leave the leaves
You may have heard that phrase a lot lately. Our beneficial insects overwinter in fallen leaves and dead organic matter. As the temperatures cool, insects go dormant and hibernate as eggs, cocoons or in small nests waiting out the cold weather. These insects will emerge again in spring prepared to do battle against the damaging insects (who also have overwintered in your garden). When you mow or dispose of the leaves, insects are killed or at least removed from the habitat on your property leaving your garden vulnerable to damaging pests next season.
The adage that leaves left on the lawn will kill the grass is unfounded. Your grass will grow back through the leaves next spring happier for the organic matter the leaves provide. But you can rake leaves onto garden beds to act as mulch or into an inconspicuous spot.
If you still prefer the look of a tidy garden, cut and trimmed, consider creating piles of organic matter in out of the way places on your property where insects can spend the winter. Heaping piles of leaves, twigs and dead plant material could become a fancy hotel for bugs behind the garden shed.
Finally, after all the outdoor work has been done and your garden is tucked in for winter, take a little more time to clean, polish and sharpen your tools. They’ve given you good service over the growing season and a little care now will keep them in good shape for a long time.
Now, make yourself a cup of tea and watch the snow fall from inside. Leaf through the seed catalogues that have started to arrive and dream of next year’s garden.