As the days get shorter and temperatures cool, the plants in your garden understand the inevitable: Winter is coming. According to their respective genetics, perennials prepare to go dormant, while annuals complete their task of producing fruit and seeds that can fall into the soil and produce new sprouts in the spring. Those annuals that serve as edible fruits and vegetables, now is typically the prime season for humans to harvest the roots, tubers, or fruit for consumption. The end result is that the garden is full of withering, dead and rotten organic material as fall gives way to winter.
You might be tempted to just leave everything as it is and let nature take its course over the winter months, but one downside of this approach is that it creates a lot of extra work for you in the spring. Moreover, insects, larvae, fungi and pathogens overwinter in the decaying material, and they will spring back to life in the spring just as surely as your dormant roses.
To keep your garden healthy, you have to remove the decaying material, and while you're at it, fall is best time to test the soil and add amendments to regulate pH and nutrient content. You might even consider planting some cover crops to keep weed growth to a minimum and replenish soil nutrients. Mulching the soil protects the roots of perennial flowers and shrubs, and autumn brings with it plenty of leaves , which is one of the best mulching materials you can find.
Start Your Preparations Early
The time for fall cleanup begins as soon as the flowers start to disappear. When you see dead or dying flowers, remove them one by one and start your compost pile in a corner of the garden. Build up this pile with grass cuttings and raked leaves to start the process of decomposition and generate some heat, which you'll need to kill larvae and fungus that will inevitably have established themselves on the decaying material. Severely moldy or insect-infested debris should be tossed into a recycling bag and removed from the garden completely or buried in trenches.
Start the cleanup process a good six weeks before the first frost. That will give you time to dig up and store existing bulbs that are tender, or to divide or plant new bulbs that overwinter best in the soil. Plant these four to six weeks before the first frost and water them well to help them establish a hardy root system so they can bring color to the garden in the spring.
Give the Soil some TLC
Fall is the best time to pick the weeds that have been plaguing the garden all summer. These should go in the trash, because the seeds can still remain viable in any compost pile that doesn't generate considerable heat. As you gradually clear the ground, this is a good time to give the soil some care.
- Loosely till the ground to expose insects and grubs that were planning to overwinter in the soil.
- Test the soil and add amendments, such as lime, sulfur or fertilizer, to regulate the pH and replenish nutrients. Doing this now gives the amendments all winter to dissolve into the soil.
- Spread a layer of compost or manure to nourish the soil.
- Cover the ground with a layer of organic mulch.
This is a great time to hand-dig perennial lawn weeds, such as dandelions, bindweed, and quackgrass. Removed now, they won't flower and spread seeds the following spring.
A mixture of shredded leaves and grass cuttings works well for mulching. An easy way to turn raked leaves into mulch is to pile them up and run over the piles with your lawnmower. Spread the mulch generously over bulbs and around perennials and young trees. It helps regulate the ground temperature and prevent frost heaving.
One way to nourish the soil over the winter and prevent erosion is to plant a cover crop. Sow seeds a good four weeks before the first frost. The choice of crop depends on where you live, so consult with the garden department at your local feed store for the best choice. Some cover crops have the effect of adding (or "fixing") nitrogen to the soil. Some can be dug into the soil the following spring to add organic material. Options include:
- Hairy vetch (Vicia villosa) Grows in United States Department of Agriculture hardiness zones 4 to 7. Note that some states consider this an invasive species.
- Crimson clover (Trifolium incarnatum), USDA hardines zones 3 to 9.
- Winter rye (Secale cereale) Zones 3 to 7.
- Oats (Avena sativa) Zones 3 to 9.
- Barley (Hordeum vulgare) Zones 4 to 8.
Caring for Perennials
Not all perennials need to be cut back at the end of the season, but some do. Among the candidates for fall pruning are peonies, which are prone to disease if left intact during the winter and hosta and irises, which become less manageable in the spring. Fall is also a good time to prune back rose shrubs. Remove dead canes and thin the shrubs by pruning back canes that cross each other or keep out light. All the material you cut should either be thrown away or burnt.
Roses and other perennials need plenty of water before they go dormant. Water regularly up to the first frost, and be sure to mulch around the roots to help the roots retain the water and maintain a stable temperature.
Prepare tress and shrubs by removing dead or diseased branches. Mulch the roots, and if you live in a cold northern climate, protect vulnerable vegetation by surrounding it with a cylinder of snow fencing and filling the cylinder with shredded leaves. Woody shrubs and trees should also be watered well in the weeks leading up to frost.
Pre-Winter Maintenance Tasks
Water expands when it freezes, and that could mean burst pipes, cracked buckets and ruined hoses when the cold sets in. To prevent damage to your garden equipment:
- Empty water from buckets, concrete birdbaths, pots and garden ornaments.
- Drain out hoses, roll them up and store them indoors.
- Drain the sprinkler or drip system.
- Turn off the water to the garden spigots, then open the spigots and let water drain. Leave the spigots open.
Before you put away your gas-powered garden tools, such as the lawnmower, leaf-blower or chainsaw, empty the gas tank, even if the fuel has stabilizer in it. The best way to do this is to run the engine until the fuel runs out, but you can also siphon the fuel into a container for disposal. Don't plan on reusing it.
Your fall maintenance regimen should include a thorough cleaning your garden tools. After cleaning, rub down the metal parts with mineral oil or vegetable oil to protect them from rust and store them in a dry place.