How to Grow and Care for Oregano

Oregano is a perennial herb that returns year after year. The most common species, Origanum vulgare, and Origanum majorana have an intense, herby, bitter flavor used in seasoning and as key ingredients in pizza, pasta sauces, Greek cuisine, and Mexican dishes. Typically planted in the spring, it grows quickly and can be eaten as soon as it grows. Research has shown its oils contain antioxidants that may have potential health benefits.

Oregano starts as a ground-hugging rosette of leaves, but it can easily grow to about 2 feet tall. Its leaves are generally oval, dark green, sometimes fuzzy, and positioned in opposite pairs along the stems. The plant can have a strong, sharp scent with notes of earth, hay, and mint. Note that oregano is toxic to pets, so be mindful of where you plant it.

How to Plant Oregano

When to Plant

Plant oregano in the spring after the threat of frost has passed. Also, you can start seeds or cuttings indoors around six to 10 weeks before your area's projected last spring frost. The outdoor soil temperature should ideally be around 70 degrees Fahrenheit for planting.

Selecting a Planting Site

Oregano is a Mediterranean herb that grows well in full sun and well-drained, lean-to-average soil. Rich soil can dilute the herb's pungency. So, oregano is a good choice for sunny garden areas with poor soil unsuitable for many other plants. Make sure it isn't situated too close to taller plants that will leaf out and shade the oregano.

Spacing, Depth, and Support

Space oregano plants around 8 to 10 inches apart. Seeds should be slightly pressed into the soil, needing light to germinate. Nursery plants should be planted at the same depth they were growing in their container. A support structure shouldn't be necessary.

Oregano Plant Care

Light

Most oregano varieties need full sun, meaning at least six hours of direct sunlight on most days. However, some varieties, including golden oregano, prefer a little shade from strong sunlight to prevent their leaves from scorching.

Soil

A sandy loam is ideal for growing oregano. If the soil is moist with organic matter, oregano won't perform as well as in well-drained, light, dry soil. Also, a slightly acidic to neutral soil pH is best.

Water

Oregano only needs about an inch of water per week and tolerates moderate drought. Allow the soil to dry out between waterings, as overwatering can cause root rot and other problems.

Temperature and Humidity

Depending on the variety, oregano can tolerate heat and even pretty cold temperatures. Its ideal growing conditions are around 60 to 80 degrees Fahrenheit. It generally does not like high humidity and must have sharp soil drainage and good air circulation in humid climates.

Fertilizer

Oregano typically doesn't need fertilization, as it can thrive in poor soil. However, large amounts of nutrients, such as nitrogen, can change the herb's flavor.

Pollination

Oregano is a great herb that attracts beneficial pollinators to your garden. Bees and other insects help to pollinate its tiny flowers.

Types of Oregano

Oregano is native to western Asia and the Mediterranean, growing best in USDA zones 4 to 10. Many types of oregano are often extracted into an essential oil.

Oregano oil has been shown to have antimicrobial, antiviral, and antifungal properties, along with other potential health benefits.

Here are some of the most common oregano varieties:

• Origanum vulgare (common oregano): This species is the one many people use for cooking.
• Origanum vulgare 'Aureum' (golden oregano): This cultivar has lighter leaves and a milder flavor than the main species plant. It is more popular as an ornamental plant than a cooking herb.
• Origanum heracleoticum (Greek oregano): This species is also commonly used for cooking and has a relatively strong flavor.

Oregano vs. Thyme

Both oregano and thyme thrive in similar growing conditions: lots of light and fairly dry soil. They also look similar at first glance. However, oregano leaves are broader and greener than thyme's typically narrow, gray-green foliage. Oregano also has a pungent, earthy aroma compared to thyme's lighter, more floral scent.

Harvesting Oregano

Once your oregano plant has reached 4 to 5 inches tall, you can begin harvesting the leaves. Trim off sprigs with just the leaves you need for cooking, leaving the rest of the plant to continue growing. Then, run your fingers down the stem to strip off the leaves. 

The most flavorful oregano leaves occur right before the plant blooms in the summer. So, if you plan to take sprigs for drying, that's the best time. But you can still snip off leaves at any point during the growing season for cooking or drying.

Fresh sprigs can be refrigerated for about a week or frozen for about a year. To dry, hang sprigs upside down in a dark, cool spot with good air circulation. Then, strip the leaves and store them in an airtight container. Dried oregano has a more robust flavor than fresh leaves and should be viable for two to three years.

How to Grow Oregano in Pots

Oregano is well-suited for growing in pots and is a good choice for a windowsill herb garden indoors. Containers generally dry out faster than garden soil, so this can help create the fairly dry environment that oregano likes.

Ensure the container you select has adequate drainage holes. Unglazed clay is ideal because it allows excess soil moisture to evaporate through its walls. A container that’s 10 to 14 inches across and 6 to 8 inches deep should suffice. 

Pruning

Oregano needs regular pinching of the back of its growing tips, beginning when the plant is about 4 inches tall. Pinching will promote a bushy growth habit and help to prevent leggy, straggly growth. It also can delay flowering, which is best if you want the leaves to be as flavorful as possible for culinary use. As the plant grows, this pinch-back ritual should be weekly.

If the plant becomes overly woody, cutting the stems back to the ground will encourage more stems to sprout from the base, ultimately resulting in a fuller plant.

Propagating Oregano

Oregano is best propagated from divisions or cuttings. (Because different species of oregano can cross-pollinate, you might not get what you expect from seeds you save from garden plants.) Dividing a mature plant and taking cuttings can help rejuvenate it, resulting in bushier growth and a healthier harvest. The best time to divide a plant is early spring or fall. Here's how:

1. Gently dig up a mature oregano plant, keeping its rootball intact.
2. Use a sharp spade or even your fingers to divide the rootball in half. Aim to tease as many of the roots apart as possible rather than cutting them.
3. Replant each segment in a suitable growing site.
   

Cuttings can be taken at any time when the plant is actively growing, though the spring and early summer are best because the stems are still green and pliable. Here's how:

1. Use sterile pruners or scissors to cut a 5-inch portion of a healthy stem. Make a diagonal cut just above a leaf node.
2. Strip off any leaves on the bottom half of the cutting.
3. Place it in a container of water in a warm, bright spot but out of direct sun. Ensure that the leaves remain above the water.
4. Refresh the water every few days. You should start to see roots appearing in about a week. Wait a few weeks for a good network of roots to form before planting the cutting.
   

How to Grow Oregano From Seed

Use seeds from a commercial seed company to ensure the plant grows true to the variety you've selected

1. Use a seed-starting mix in a small container, keeping it moist but not soggy.
2. Cover the oregano seeds very lightly with soil since they require some light to germinate.
3. Place the container in a warm spot—roughly 70 degrees Fahrenheit—and in bright, indirect light.
4. Harden off the seedlings before planting them outside. Germination should occur within a week.

Potting and Repotting Oregano

For potted oregano, you can use any well-draining, general-purpose potting mix. Consider blending it with extra sand, perlite, or vermiculite to improve drainage. It's generally a good idea to repot a mature oregano plant every couple of years, dividing it as necessary to ensure light reaches all plant parts.

Overwintering

Oregano generally only requires overwintering maintenance in zones 4 and colder, though be sure to check the growing requirements of your particular variety.

In cold winter climates, cut back the stems of the oregano plant after the first frost kills the foliage. Leave a short umbrella of stems to protect the root ball. Also, cover the soil with 3 to 4 inches of dry mulch for the winter. Remove the mulch in the spring as soon as the snow melts.

Common Pests and Plant Diseases

Few pests and diseases bother oregano plants. However, watch for spider mites and aphids on the foliage. Also, inspect the plant for signs of root rot and other fungal diseases that can arise in wet soils. Correcting the oregano plant's growing conditions can often help resolve minor pest and disease issues.