How to Prep Your Garden for the Winter


Here in Boulder County, it seems like just yesterday we were getting our gardens all ready for spring. Now, the end of the season is already upon us! 

While you’re harvesting the last of your squash, kale, and root crops this fall, you should start thinking about your winter prep to-do list for the garden.

There’s always the option to simply leave your garden be once fall and then winter rolls around. But with a little work now, you can increase your chances for a fruitful bounty next season.

The benefits of your prepping your garden for the winter include:

  • Removes plant diseases and invasive weeds from your garden
  • Strengthens the soil
  • Helps perennials and annuals for overwintering
  • Leaves your garden ready for planting in the spring

From getting rid of dead plants and weeds to enhancing your soil and cleaning up your tools, here are 8 ways to prep your Boulder County garden for winter.

Remove Dead Plants

Besides perennials and annuals, everything in your garden should go. Once the plants have fully died off, you can easily pull them out from the roots.

If the plants in your garden suffered from pests, fungal infections, or plant diseases, you should dispose of them. Diseases can live in your soil or compost. Pests lay eggs that remain dormant over the winter, ready to attack your garden as soon as spring hits.

If the plants were healthy before they died, they can make a great addition to your compost pile. Or you can bury them directly into the soil of your garden to add healthy organic material to your garden bed.

Get Rid of Weeds

As the fall gets colder, weeds will become weaker and easier to pull out. Now is a good time to get rid of all you garden invaders and throw them away.

Don’t add weeds to your compost, as many of them can survive in your compost pile. That means you’ll be adding them right back into your garden the next time you mix compost into your soil.

Care for Perennials and Bulbs

Some plants stay in garden year-round. These include asparagus, rhubarb, berries, and many herbs.

Most of these benefit from fall pruning. Blueberries and raspberries are a few exceptions — it’s best to prune these in the spring.

Flowering bulbs should be dug up, gently separated as needed, and transplanted with appropriate spacing. Now’s also a good time to plant bulbs such as tulips and daffodils.

Enhance and Protect Your Soil

One of the best things to do before winter is care for your garden’s soil. Once you’ve removed dead plants and weeds and tended to your overwintering garden inhabitants, do the following to set your soil up for springtime success:

Test Soil

  • A pH test can tell you the acidity levels present in your garden’s soil. Different pH levels can support different types of plants or veggies.
  • If your soil is too acidic, you can raise the pH by adding alkaline substances, such as limestone (available in your local garden store) or wood ash from your fire pit.
  • You can lower pH by adding acidic materials to your soil. These include organic compost, manure, coffee grounds, and store-bought sulfur and aluminum sulfate.
  • Tilling pH-altering substances of choice into the soil before winter will give them time to break down in your garden and change the pH before spring planting.

Till to Remove Pests

  • Bugs and their eggs can live in your garden’s soil over the winter. if you let them be, they’ll be ready to wake up or hatch as soon as springtime rolls around — and they’ll be hungry for whatever you’re planting.
  • Tilling the soil a few inches deep should expose most pests and decrease their numbers in your garden next year.

Add Compost

  • Apply a layer of compost to your garden and till it into the soil. Compost adds beneficial organic matter to your soil and makes it healthier.
  • Adding it before winter gives it time to settle into and become a part of your garden’s ecosystem.
  • If you have extra finished compost after amending your soil, you can either pile it directly on top of your soil or store it in loosely covered bins or pails in your shed, garage, or crawl space — anywhere that will protect the compost from frost and allow microbes to continue to thrive.

Side note: You can keep your compost pile going all winter long. If it’s not in a compost bin, you should cover it to keep unwanted hungry pests out and to help maintain its internal temperature.

Layer Mulch

  • Once your soil has been tilled and amended with pH-altering materials and compost, layer mulch over the entire garden.
  • Fallen leaves from your yard are a free and great option for winter mulch. This will protect the soil from harsh winter weather, improve moisture retention, and help keep weeds from growing.
  • A thin layer of mulch (1-2 inches) will also help moderate the soil temperature to prevent continuous thawing and re-freezing, which is bad for the soil and for any overwintering plants’ root systems.

Plant Cover Crops

  • An alternative option to mulch is to plant cover crops such as clover, rye, or field peas.
  • These crops protect the soil in a similar way as mulch, with the added benefit of supplying extra nutrients to the garden. Legumes like peas boost nitrogen levels, which is great for many plants.
  • You’ll still need to clean your garden of cover crops before you can plant in the spring.

Take Notes for Next Year

The end of the season is a great time to take stock of what worked well and what didn’t over the spring and summer.

Make note of which varieties and plants thrived, and which suffered from pests and disease. Write down how much watering worked best for different plants.

It’s also not a bad idea to track how much fruit your get from different varieties so you can compare year-to-year to see what’s helping you improve your crop. If you don’t do this now, you might forget by the time spring rolls around.

Clean and Store Garden Tools

Once your garden is fully prepped for winter, you won’t be needing most of your garden tools for a number of months. This is a good time to get them tuned up, cleaned, and put away for the winter.

Scrub them clean of any dirt, and scrape rust away with sandpaper. You can sharpen tools such as hoes, shovels, and pruners with a file or whetstone. You can also take the tools to your local garden or hardware store, many of which offer sharpening services.

After cleaning and sharpening, apply some machine oil with a cloth to protect the metal from oxygenation, then store in a safe, dry place, like the garage or shed.

Winterize Your Sprinkler System

If you use a sprinkler system to water your garden and lawn, you’ll also want to lock it down for winter with the following steps:

  • Turn off the sprinkler water supply
  • Wrap the shut-off valve in insulating material to keep it from freezing
  • Shut down sprinkler control system
  • Drain sprinkler pipes of water

What to Do with Harvest Abundance

Your garden is all ready for winter, and hopefully your pantry is stuff with the bounty of this year’s harvest!

If you don’t think you can eat it all before it goes bad, you can always freeze, jar, or donate extra food to Boulder County organizations such as Community Food Share or Boulder Food Rescue.

Getting the Rest of Your Home Ready for Winter

The garden is just one aspect of your home that needs to be prepped for winter. From the roof and gutters to your chimney and lawn, there’s a lot to be done.

The pros at GSC are ready to help. Check out our Boulder Homeowners Pre-Winter Checklist »