I first posted this back in 2009, but (with one exception, below) my advice hasn’t changed. While I‘m off looking for migrating warblers today, you should be out in your garden. Here’s why:
- Spending time now on chores such as weeding and garden cleanup will reward you many times over when spring arrives.
- Amending your soil this fall will give you a head start on next year’s garden.
- Fall is also a great time to build a new patio or raised bed.
- Protecting your less-hardy plants will increase the odds of them surviving a Colorado winter.
- Winter’s cold weather is a great time to read articles, take classes, and prowl the Internet to become a more knowledgeable gardener.
- And the most pressing issue? The weather gurus are predicting snow tonight and/or tomorrow!
Although most people try to avoid it, weeding is absolutely essential. All those weeds are full of seeds, just waiting to sprout at the first sign of spring. Pull them up or mow them down, but get them out of your garden! Most compost piles won’t get hot enough to kill weed seeds. A little effort now will reap huge benefits later.
Some nasty insects and diseases overwinter on dead foliage, so eliminating weeds will also reduce next year’s pest problems.
Waiting until spring to trim back many perennials and grasses allows them to provide interest to your winter landscape. The dried stems trap snow, insulating the roots and keeping them moist. Plus, leaving above-ground foliage reminds everyone to avoid walking in the garden beds.
However, it’s best to remove and dispose of the top growth of perennials that were diseased, had insect problems, or that are unattractive in winter. Go ahead and pull up those dead annuals, as well.
You can compost healthy plants. Simply mix equal amounts of dead, brown plant matter, and fresh, green leaves and kitchen scraps. Making a pile at least three feet on a side will help it stay moist. Be patient. It may take more than a year to make compost in our cool, dry climate. Shredding the ingredients will help them rot faster.
A few things don’t belong in the compost pile. Fats and meats attract unwanted wildlife. Our soils are already high in calcium, so leave out the eggshells. Tomato plants should not be used in garden compost. Tomato Early Blight is a common disease along the Front Range, and composting infected vines will spread it to next year’s plants.
Now that you have those dead plants out of the way, it’s time to amend your soil. A soil test will tell you exactly what nutrients your garden needs. Fall is a good time to apply fertilizers containing potassium and phosphorus, because these nutrients last a long time in the soil. However, nitrogen added now will be gone in six months, so it’s best to wait until spring.
Colorado soils are notoriously lacking in humus, or decomposing organic matter. Humus allows clay soils to drain better, while helping sandy soils retain water. Having enough humus also encourages earthworms and other small soil-dwelling creatures, which in turn help your plants grow.
Here’s where my advice has changed, due to some surprising new research findings. Early fall is the best time to increase humus levels by mixing in organic amendments such as compost or manure. While fresh manure used in the spring can burn plants and transmit diseases, adding it now will give it time to age, solving both problems.
However, avoid manure from feed lots and other typical agribusiness sources. It contains toxic levels of salt, which doesn’t leach well in our dry climate. Also, the cows in many dairy operations stand in a thick layer of wet manure all day. Solutions containing zinc and copper are used to prevent and treat hoof disease resulting from these conditions, and these elements can build up in the manure. While plants need some zinc and copper, continually adding dairy manure to your soil can result in toxic levels of these elements.
How much amendment should you use? First have your soil tested to see whether you need any more humus. (My most recent test showed that I have too much!) If needed, spread a layer three to four inches deep across the bare soil in your planting area, and dig it in throughout the root zone, about one to two feet deep.
Once your soil is ready for spring, a layer of mulch will protect it through the winter. If your trees are healthy, their fallen leaves make terrific mulch. Using your mower to shred them keeps your garden neat-looking. Straw is cheap and readily available, although it may carry weed seeds. Or, try placing a few layers of newsprint over the soil, topped with grass clippings. Whatever you do, don’t leave the soil exposed. Winter mulches encourage earthworms, reduce compaction, and discourage soil-borne pests.
Plants that would be happier in a warmer climate will appreciate some coddling as severe weather approaches. Rose collars filled with mulch will insulate the roots and stems of more than just roses. Wrapping the bark of newly planted trees protects them from being scorched by the intense winter sun. If you are overwintering a broad-leafed evergreen shrub such as Firethorn (Pyracantha), consider using one of the foliar sprays that reduce water loss from the leaves. It’s difficult for a plant to replace that water when the ground is frozen solid.
Our erratic winter weather may cause some problems. A warm spell may fool plants into sprouting. The cold that follows then damages tender new growth. Also, the alternating freezing and thawing of the ground causes the roots of plants to be heaved out of the soil. A two- to-four-inch layer of mulch will keep the ground frozen and the plants dormant. Snow insulates the soil, and keeps it from dipping much below 32º. Our dry winters leave the ground exposed much of the time. Mulch keeps the roots from getting too cold, killing an otherwise hardy plant.
If this isn’t enough to keep you busy, much more can still be done. Autumn is the best time to build garden improvements such as raised beds, new planting areas, and patios. The soil will have a chance to settle, and you will be ready to plant come May.
Keeping your tools in good working condition will make your garden tasks easier.
Also, fall is a great time to order catalogs, catch up on your garden reading, and take classes. The best plans for spring are made while this year’s successes and failures are fresh in your mind.
Early fall weather brings an invigorating briskness that invites us back into our gardens. Don’t resist. Winter will come soon enough—then you can take a well-deserved rest.
* It’s best to get a soil test prior to adding either humus or fertilizer. There is such a thing as too much!