Geranium in Zone 5A — Midwest

Geraniums are a Midwest garden staple, bringing vibrant color and a classic touch to our porches and flower beds. Their adaptability to our summer heat spells makes them a reliable choice, and their long blooming season keeps the garden looking lively.

The Midwest weather can be unpredictable, especially in spring, but with a little planning, you can enjoy beautiful geraniums all season long. Our 157-day growing season provides plenty of time for them to thrive if you get them started at the right time.

Starting geraniums from seed indoors is possible, but honestly, they're very slow-growing, so you'll need patience. If you're up for the challenge, begin in mid-February through early March, about 12 weeks before you plan to transplant.

Use seed trays with a good seed-starting mix and provide warmth and light, like a heat mat and grow lights. Water from the bottom to prevent damping-off. Given our moderate-to-late springs here in the Midwest, starting early indoors gives them a head start.

For the easiest results, buy geranium starts from your local garden center. But if you've started your own, transplant them outdoors in mid-May through mid-June, once the danger of frost has passed – and after you've waited until Memorial Day, just to be safe!

Harden them off for about a week beforehand, gradually exposing them to outdoor conditions. Space them 10-12 inches apart in fertile soil. Keep an eye on the weather forecast; we can still get some unexpected cold snaps even in late May.

Geraniums need moderate watering, and it's key to let the soil dry slightly between waterings. Overwatering can quickly lead to stem rot, especially with our moderate-to-humid summers. They do tolerate our summer heat spells better than many other flowers, though.

During the active growing season, from late spring through summer, give them about 1 inch of water per week, either from rainfall or irrigation. Stick your finger about 2 inches deep into the soil – if it feels dry, it's time to water. Water at the base of the plant to avoid wetting the foliage, which can encourage fungal diseases in our humid climate. Yellowing leaves can indicate overwatering, while wilting suggests they need a drink. Mulching around the base of the plants helps retain moisture and regulate soil temperature.

Deadheading is essential for geraniums. Throughout the growing season, pinch off spent flower clusters right where the stem meets the main stalk. This encourages continuous blooming and keeps the plant looking tidy.

If you notice any leggy stems, pinch them back to promote bushier growth. As the first frost approaches in early October, you can bring your geraniums indoors to overwinter, or you can compost them and start fresh next spring.

Geraniums aren't really "harvested" in the traditional sense, but you can expect them to bloom from late July through mid-September. The "harvest" is really just enjoying their beautiful flowers throughout the summer.

Remove any faded or dead blooms regularly to keep the plant looking neat and to encourage more flowers. Deadheading will significantly extend the blooming period. As the weather cools in early October, you can take cuttings to propagate new plants indoors over the winter.

Here are some common problems to watch out for with geraniums in the Midwest:

Botrytis Blight

• What it looks like: Grayish-brown mold on flowers, leaves, and stems.
• What causes it: High humidity and poor air circulation, common during our wet summers.
• How to fix/prevent it: Remove infected parts promptly. Provide good air circulation by spacing plants adequately. Water at the base of the plant.

Geranium Budworm

• What it looks like: Small holes in flower buds and leaves, often with dark droppings nearby.
• What causes it: Caterpillars feeding on the plant.
• How to fix/prevent it: Handpick caterpillars when you see them. Use insecticidal soap if the infestation is severe.

Edema

• What it looks like: Small, blister-like bumps on the undersides of leaves.
• What causes it: Excessive moisture in the soil and cool temperatures, often during our variable spring weather.
• How to fix/prevent it: Improve drainage. Avoid overwatering. Provide good air circulation.

Midwest Specific Challenges: Our moderate-to-hot heat, moderate-to-humid humidity, and wet-summer rainfall create conditions that can favor fungal diseases like botrytis blight. Be vigilant about watering practices and air circulation to keep your geraniums healthy.

Geraniums play well with several common Midwest garden plants:

• Tomatoes: Geraniums can help repel certain tomato pests, like the tomato hornworm.
• Peppers: Similar to tomatoes, geraniums can act as a deterrent for pepper pests.
• Corn: The strong scent of geraniums can confuse certain corn pests, making it harder for them to find their host plant.
• Roses: Geraniums can help repel aphids, which are common rose pests.

Avoid planting geraniums near plants that prefer very dry conditions, as their moderate watering needs might lead to problems for those companions.