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Greenhouse Gardening - How to Grow Oregano?

How to Grow Oregano in a Greenhouse

Table of Contents

It is so easy to grow oregano in a greenhouse at any time of the year. This popular pizza herb is a perennial plant, which means that it lives for more than two years. It rises as a shrub that can stretch up to 29 inches high. Its leaves are a tiny, oval, and grayish-green color. It has purple edible flowers found on the tips of stabilized stems. It also promotes the growth of neighboring plants.

Did we mention the pizza herb? Did you know that nearly all pizza recipes have oregano as an essential ingredient? Oregano became famous in the USA after World War II when American soldiers returned from the battlefields in Italy. Aside from serious war flashbacks, they also brought the spice oregano as they were craving pizza.

Serving a cup of oregano tea

Interesting facts about oregano

  • Oregano is best known as the “pizza herb”. Aside from that, it is also used as an essential ingredient for some popular Italian specialties such as pasta and tomato recipes.
  • The benefits of oregano tea or ointment are said to be therapeutic.
  • Growing oregano in your greenhouse can scare some pests away because it acts as a natural insecticide.
  • It has a very deep history of usage as a medicinal herb before it was used for cooking.
  • People use it against seasickness.
  • It is a great source of Vitamins A, B6, C, E, and K as well as magnesium, iron, calcium, and potassium.
  • It also has antifungal and antimicrobial characteristics.
  • Farmers use oregano in a huge amount to feed their animals because they think that eating this herb will encourage the animals to provide sweet milk. This is the reason why it is called sweet marjoram.
  • Based on a myth, the Greek Goddess Aphrodite formulated aromatic oregano as a representation of her happiness and planted it in her garden on Mount Olympus.
  • Growing oregano in a garden is believed to protect us from evil. So, let’s try this!
  • Now you got all the reasons to raise this in your own greenhouse garden.
  • Dried leaves are used to enhance the taste of salty meals.

Quick overview of growing oregano in a greenhouse

  • Type: Warm-season crop, perrenial
  • Time from seed to harvest: 60-90 days
  • Germination temp: 45°F or warmer
  • Time until first emergence: 7-14 days
  • Best temp to grow: 60-80°F
  • Height: 1-3 ft
  • Spread: 2-4 ft
  • Light: Full sun (6-8h)
  • Grow from seed: 1/4 in deep in rows 12-18in apart
  • Companions: Strawberries, asparagus, rosemary, thyme, basil, cabbage
  • Keep away from: Lettuce, raspberries, collards

How to grow oregano in a greenhouse

Oregano is so easy to grow in any greenhouse. Here is how:

  • You can grow oregano from seed or use cuttings from mature plants.
  • The preferred spacing is between 8-10 inches apart in rows that are about 20 inches apart.
  • Oregano requires a moderately fertile, well-drained neutral to slightly alkaline soils with pH ranging from 6.0 to 7.2.
  • When the plants attain a height of four inches, pinch the bud or trim the plant lightly. This encourages the oregano plants to get denser or grow bushier.
  • Routine pruning will not only make the herb to branch again but also prevent legginess.
Dried and fresh oregano leaves with the text: How to grow oregano in a greenhouse.

Oh, yeah, the pests…

Some common pests and diseases that attack oregano plants are spider mites, aphids, as well as root and stem rot. Here’s how to solve these:


Aphids may cause leaves to become yellow and distorted. Always check cuttings before planting. Strong plants can be sprayed with a solid stream of water to remove aphids from the leaves. Insecticides are only needed if there is a serious infestation.

Spider mites

Spider mites look like small moving dots underneath the leaves. It is normally not detected until you see indications on your herb. Spraying with a strong stream of water can help lessen the growth of spider mite populations.

Root and stem rot

The fungi that cause disease obstacles in oregano usually result in rotting roots or leaves. If the matured leaves in the middle start to rot, it is probably contaminated. Sadly, there is no remedy for this. You should remove the plant to stop the infestations. Never plant oregano in the very spot for at least three years.

Fresh and dried oregano leaves grown in a greenhouse

How much water does oregano need

In your greenhouse, and even out in the open, oregano requires comparatively little water. Water the plants when the ground feels dry to your touch. The appropriate amount is two to three gallons per plant every fortnight. If it is planted in a container, you have to water until it comes out of the holes.

Proper lighting and temperature in your greenhouse

You need to have plenty of direct sunlight if you want to grow oregano in your greenhouse. Place the herb in a spot facing the south. Install an elegant herb shelf on the south side in your greenhouse! Suitable soil temperature should be about 70°F. This herb can stand some cold but it will thrive best when the temperature doesn’t drop below 59°F. Try these Greenhouse Heaters to control the temperature especially in winter.

Time to pick your oregano!

To enjoy the full flavor of oregano, harvest the leaves just before the plants start to flower. Harvest by cutting branches slightly above the joint with the stem. They are picked in pairs that are reversely arranged on its branches. This herb is self-seeding and will surely grow again.

You can either freeze the leaves or dry them to have it always available for your favorite Italian dishes. Store them in airtight jars once dried.

FAQs about growing oregano in a greenhouse

Does oregano come back every year?

Oregano is a perennial herb which will thrive year-round in most climates. It tolerates cold temperatures to 40°F and is frost-sensitive. The ideal temperature for growing oregano is 60-80°F and it is perfectly suited for greenhouse growing year-round.

What does an oregano plant look like?

Oregano plant grown in a greenhouse

Oregano leaves are small with an oval shape and are sometimes a bit fuzzy. The opposite leaves have a rosette pattern of growth. They range in color from light to dark green, depending on the amount of sunlight they receive and the variety of oregano. Oregano is a small clumping plant that has a spread of about 1-2 feet and may have small white, blue, or purplish flowers when in bloom.

How tall does oregano grow?

Oregano can range in height from 1-3 ft.

What are your favorite ways to enjoy oregano? Tell us by leaving your ideas below.
Picture of Jesse James
Jesse James

Jesse James, an Army Veteran, now shares his passion for gardening through engaging articles on Greenhouse Emporium. Leveraging his experience and love for nature, Jesse provides practical advice and inspires others on their gardening journey.

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