As the temperatures begin to drop, it's time to think about protecting your outdoor plants from the cold! Many of your favorite herbs, perennials, and potted plants can be overwintered indoors, saving them from frost and giving them a head start for next spring.

Here are the steps for successfully bringing your plants indoors and keeping them healthy through the winter months.

Why Overwinter Your Outdoor Plants Indoors?

Certain plants, especially tender perennials and herbs, can’t survive harsh winter conditions. Rather than losing them to frost, you can bring them inside where they'll continue to grow, or go dormant until they’re ready to return outside in spring. Plus, overwintering plants indoors can also add some lovely greenery to your home during the colder months.

Step-by-Step Guide to Overwintering Plants Indoors

1. Choose the Right Plants

Not all plants need to be brought inside. Focus on the following:

• Herbs: Basil, rosemary, mint, and thyme are great candidates.
• Tropical plants and tender perennials: Plants like begonias, geraniums, and hibiscus need indoor protection.
• Potted plants: If they’re not hardy in your zone, it's best to move them inside.

If you're unsure, check the plant’s hardiness zone and compare it to your local winter temperatures.

2. Inspect Plants for Pests

Before bringing any plants indoors, make sure they’re pest-free. Here’s how:

• Check leaves and soil for insects like aphids, spider mites, or whiteflies.
• Treat with natural insecticidal soap or gently rinse leaves with water to remove any pests.
• Consider repotting: If you suspect pests are hiding in the soil, repot the plant in fresh potting mix before bringing it indoors.

3. Gradually Transition Plants

Moving plants directly from outside to a warm indoor environment can shock them. To minimize stress, follow these steps:

• Start by bringing them indoors for a few hours a day, gradually increasing the time over a week.
• Place them in a shaded area indoors for a few days before moving them to their permanent spot, so they can adjust to the reduced light.

4. Find the Right Spot Indoors

Plants that have been outside all summer may need different conditions when moved inside. Here are some tips:

• Light requirements: Many outdoor plants need bright, indirect light. Place them near a south- or west-facing window, or consider using grow lights if natural light is limited.
• Humidity: Indoor air can be dry during winter. Group plants together or place a small humidifier nearby to increase humidity levels.
• Temperature: Keep plants away from drafts or heat sources like radiators. Most plants prefer a steady temperature around 60-70°F (15-21°C).

5. Adjust Watering and Care

Plants use less water indoors during winter because they’re not actively growing. Here’s how to care for them:

• Water sparingly: Let the top inch of soil dry out between waterings to avoid overwatering, which can lead to root rot.
• Avoid fertilizing: Most plants go into a dormant phase in winter, so hold off on feeding until spring when new growth starts.
• Monitor for pests: Even indoors, pests can still pose a problem, so keep an eye out for signs of trouble.

Herbs That Thrive Indoors

Looking to keep your herb garden going through the winter? Here are a few that can thrive indoors:

• Basil: Loves bright light, so keep it near a sunny window.
• Rosemary: Prefers cooler temperatures and plenty of light.
• Mint: Easy to grow indoors with moderate light and regular watering.
• Parsley: Perfect for a sunny windowsill and doesn’t need much space.

Basil PlantPhoto byRobin Phelps/Sow Many Plants

Bonus Tips for Overwintering Success

• Prune and trim: Cutting back leggy growth before bringing plants indoors encourages more compact, healthy growth.
• Rotate plants: Turn pots every week to ensure even light exposure and prevent them from leaning toward the light source.
• Mist your plants: If the air is particularly dry, mist your plants with water to help maintain humidity.

By following these steps, you can keep your outdoor plants happy and healthy indoors all winter long. Not only will you be protecting your garden investments, but you’ll also get to enjoy their greenery throughout the colder months!

Edward C. Smith, The Vegetable Gardener's Bible, Storey Publishing, 2009