The Ultimate Guide to Safely Overwintering Geraniums in Pots

 Geraniums (Pelargoniums are the common bedding plants) are tender perennials. This means they are beautiful annuals in most of the US, but they can be saved and enjoyed year after year—if you protect them from the cold.

Overwintering your potted Geraniums is a rewarding way to get a head start on next spring’s gardening and save money. The key is knowing which method is best for your space.

Step 1: Pre-Winter Prep (Before the First Frost)

Timing is crucial. You must bring your Geraniums inside before the first hard frost. A light freeze is often enough to kill the entire plant.

1. Prune and Clean

• Cut Back: Use clean, sharp pruners to cut the plant back by one-third to one-half. This reduces the amount of foliage the plant has to support over the winter and encourages bushy new growth in the spring.
• Deadhead: Remove all remaining flowers, buds, and yellow or dead leaves.
• Sanitize: Clean the surface of the soil and the outside of the pot.

2. Check for Pests

This is the most critical step to prevent indoor infestation.

• Thoroughly inspect all leaves (especially the undersides) and stems for pests like aphids, spider mites, or whiteflies.
• If you find any pests, treat the plant with an insecticidal soap before bringing it inside, or discard heavily infested plants. Do not bring sick or buggy plants indoors.

Geranium

Step 2: Choose Your Overwintering Strategy

You have two main options for bringing your potted Geraniums indoors, depending on the space and light available in your home.

Option A: The Houseplant Method (Keep Them Growing)

If you have a bright, sunny window and moderate indoor temperatures, you can treat your Geraniums like any other houseplant.

Requirement	Details for Success
Location	A south- or west-facing window is best. If natural light is lacking, use a simple LED grow light positioned a few inches above the plant for 12-14 hours per day.
Temperature	Geraniums prefer cool temperatures when growing indoors: ideally 55°F to 65°F (13°C to 18°C). Avoid placing them near heat vents or fireplaces, which can dry them out.
Watering	Water sparingly—much less than you did in the summer. Wait until the top inch of soil is completely dry to the touch before watering again. Overwatering is the #1 killer of overwintered Geraniums.
Feeding	Do not fertilize during the winter months. The goal is to sustain, not encourage vigorous growth.
Pinching	If the plant starts to look “leggy” (spindly, reaching for the light), pinch back the new growth tips to encourage a bushier shape.

Option B: The Dormancy Method (Cool, Dark Storage)

This is the preferred method for gardeners with limited indoor space. The goal is to force the plant into a semi-dormant, resting state.

1. Preparation: Prune the plant back aggressively (about 4–6 inches of stem). Allow the soil in the pot to dry out for a few days after the final watering.
2. Storage Location: Store the pots in a cool, dark, and frost-free location like an unheated basement, garage, or cellar. The ideal temperature range is 45°F to 55°F (7°C to 13°C).
3. Watering: This is critical. Check the pots about once a month. If the soil is bone-dry or the stems look shriveled, give them a small amount of water—just enough to keep the roots from completely drying out. The plant is barely active and requires almost no moisture.
4. Air Circulation: Good air movement is vital to prevent mold and mildew (gray mold). Do not tightly pack the pots together.

Step 3: Waking Them Up (Spring Revival)

Around 6 to 8 weeks before your last expected frost date, it’s time to wake your Geraniums up.

1. Pruning: If you used the dormancy method, prune the plants down to about 4 inches and remove any dead or moldy wood.
2. Repotting: Replant them in a new container with fresh, sterile potting mix. This provides a boost of nutrients and fresh aeration.
3. Light and Water: Move the pots to a bright, warm location (a sunny window). Begin watering normally, ensuring the soil drains well.
4. Feeding: Once you see vigorous new growth, begin a light feeding with a balanced liquid fertilizer.
5. Harden Off: After the danger of frost has passed, gradually reintroduce the plants to the outdoors over a period of 7–10 days, increasing sun exposure slowly to prevent leaf burn.

• Water Deeply, but Infrequently: Allow the top inch of soil to dry out completely between waterings.
• Check Daily: Due to the shallow nature of window boxes and the sun exposure, you may need to water daily in extreme summer heat. Always check the soil first with your finger.
• Water the Soil: Direct water straight onto the soil, avoiding the leaves and flowers, which helps prevent fungal diseases.

Deadheading and Pinching

These two maintenance tasks are the secret to a full, bushy box overflowing with flowers.

• Deadhead Regularly: Remove spent or faded flower heads entirely. Follow the flower stem all the way down to where it meets the main stem and snap it off (a clean break) rather than just pulling off the bloom. This encourages the plant to produce new flower buds instead of seeds.
• Pinch for Bushiness: If a plant looks “leggy” (tall and sparse), pinch off the growing tip of the stem just above a leaf node. This forces the plant to branch out, resulting in a much fuller, more attractive plant.
Article copyright by GreenShip