Looking for herbs and spices that start with O? It is a shorter list than some letters, but there are still plenty of useful ingredients to know about. Some are everyday cupboard heroes, such as oregano and onion powder. Others, like orris root or osmanthus flowers, are more specialist and often used in baking, drinks, perfumery or traditional cooking.

This guide covers the most relevant O herbs, spices and seasoning ingredients, with practical ideas for using them, budget-friendly tips and simple substitutes if you do not have them to hand.

Herbs and Spices That Start With O: Quick List

Here is a handy overview before we get into the details.

Oregano

Oregano is probably the best-known herb beginning with O. It is a staple in Italian, Greek, Turkish and Mexican cooking, and dried oregano is one of the most useful jars to keep in the cupboard.

The flavour is earthy, aromatic and slightly peppery. Dried oregano is stronger and more concentrated than fresh, so you need less of it.

How to use oregano

• Sprinkle over homemade pizza before baking.
• Add to tomato pasta sauce, chilli, lasagne and bolognese.
• Mix with olive oil, lemon juice and garlic for a quick marinade.
• Use in Greek-style salads with feta, cucumber and tomatoes.
• Add to roasted peppers, courgettes, aubergines and potatoes.

Money-saving tip

Dried oregano is usually cheaper per use than fresh. Buy it in refill bags or larger packs if you use it often, then decant into a small jar. If it smells dusty rather than aromatic, it is past its best, but old oregano can still be used in long-cooked sauces rather than thrown away straight away.

Onion Powder

Onion powder is made from dehydrated onions ground into a fine powder. It is not a herb in the strict botanical sense, but it is widely used as a spice and seasoning.

It gives food a savoury onion flavour without the texture of chopped onion. It is especially handy when cooking for fussy eaters who dislike onion pieces.

Best uses for onion powder

• Homemade spice rubs for chicken, pork, tofu or vegetables.
• Burger mixes, meatballs and veggie patties.
• Soups, stews and gravies.
• Seasoned wedges, chips and roast potatoes.
• Quick dips mixed with yoghurt, mayo or soured cream.

Substitute for onion powder

If you do not have onion powder, use garlic powder for a different but still savoury flavour, or add finely chopped onion where texture is not an issue. Onion granules can be used in the same way, though they are slightly coarser.

Onion Flakes

Onion flakes are small pieces of dried onion. They soften as they cook and are excellent for slow-cooked dishes where you want onion flavour without chopping fresh onions.

They are particularly useful for camping, student cooking, packed lunch prep and emergency store cupboard meals.

How to use onion flakes

• Add directly to soups, stews and casseroles.
• Stir into savoury scone, bread or muffin dough.
• Soak briefly in warm water before adding to dips.
• Use in dry soup mixes or homemade seasoning blends.

As a rough guide, onion flakes are more concentrated than fresh onion. Start small, taste, then add more if needed.

Onion Salt

Onion salt is a blend of salt and onion powder or granules. It is convenient, but it can make food too salty if you use it as freely as onion powder.

It works well as a finishing seasoning for chips, eggs, popcorn, wedges and grilled vegetables. It can also lift simple budget meals such as beans on toast, jacket potatoes or a quick omelette.

Budget note

You can make a simple version at home by mixing onion powder with fine salt. Start with more onion powder than salt so you keep control of the seasoning. Store it in a clean, dry jar.

Onion Seeds

Onion seeds is a name often used in UK supermarkets for black seeds sprinkled on naan bread, but they are usually nigella seeds, not true seeds from an onion plant. You may also see them labelled as kalonji or black onion seed.

They have a peppery, nutty, slightly bitter flavour and are common in South Asian and Middle Eastern cooking.

How to use onion seeds

• Sprinkle on naan, flatbread or savoury pastry before baking.
• Add to pickles and chutneys.
• Use in spice mixes for lentils, potatoes and curries.
• Toast lightly to bring out their flavour.

A little goes a long way. If you are new to them, start with half a teaspoon in a dish and increase next time if you like the flavour.

Orange Peel

Orange peel is a brilliant spice cupboard ingredient. Dried orange peel brings a sweet, citrusy bitterness to both sweet and savoury dishes. It is used in baking, Chinese five-spice style blends, festive drinks, marinades and desserts.

Ways to use dried orange peel

• Add to mulled wine, mulled cider or spiced apple juice.
• Use in fruit cakes, biscuits, gingerbread and chocolate desserts.
• Add a pinch to beef stews or rich tomato sauces for brightness.
• Mix with chilli, garlic and soy sauce for a citrusy marinade.
• Grind into powder and add to spice rubs.

How to make dried orange peel at home

If you are using oranges anyway, save the peel and reduce waste. Wash the orange first, then remove thin strips of peel, avoiding too much white pith as it can be bitter. Dry the strips in a very low oven or dehydrator until completely dry and brittle. Store in an airtight jar away from light and moisture.

For food safety and quality, make sure the peel is fully dried before storing. If it feels bendy or damp, it needs longer.

Orange Zest

Orange zest is the freshly grated outer peel of an orange. It is not usually sold as a dried spice, but it behaves like a flavouring herb in cooking: small amounts add a lot of aroma.

Use orange zest in cakes, pancakes, salad dressings, couscous, cranberry sauce, buttercream, marinades and chocolate puddings.

Frugal kitchen tip

Zest oranges before juicing or eating them, then freeze the zest in a small labelled container. You can add it straight from frozen to cake batter, sauces and marinades.

Orange Blossom

Orange blossom is usually used as orange blossom water rather than a dried spice. It is made from the blossoms of bitter orange trees and has a delicate floral flavour.

It is popular in Middle Eastern, North African, Mediterranean and French-inspired desserts. It can turn a simple rice pudding, syrup or sponge cake into something far more fragrant.

How to use orange blossom water

• Add a few drops to fruit salad.
• Stir into honey or sugar syrup for baklava-style desserts.
• Use in cakes, biscuits and madeleines.
• Add sparingly to cocktails, mocktails or lemonade.
• Mix with yoghurt and chopped fruit.

Be careful with the amount. Orange blossom water can taste soapy if overused, so start with a quarter teaspoon and add more only if needed.

Orris Root

Orris root comes from the rhizome of certain iris plants. Once dried and aged, it develops a floral, violet-like aroma. It is best known as a botanical in gin and some liqueurs, and it is also used in perfumery.

In the kitchen, orris root is a specialist ingredient rather than an everyday spice. You may find it in old-fashioned recipes, homemade bitters or drinks infusions.

How to use orris root

• Use tiny amounts in homemade botanical blends.
• Add to infusions where a floral note is wanted.
• Combine with citrus peel, coriander seed and juniper in gin-style flavouring experiments.

Buy food-grade orris root from a reputable supplier if you plan to consume it. Do not use craft or potpourri-grade botanicals in food or drink.

Old Bay Seasoning

Old Bay seasoning is a famous American seasoning blend rather than a single herb or spice, but it earns a place in an O list because many cooks search for it by name. It is typically associated with seafood and has a savoury, celery-salt warmth with paprika and other spices.

It is not always cheap in UK supermarkets, but you can use it sparingly as a punchy finishing seasoning.

Best uses for Old Bay seasoning

• Sprinkle over prawns, crab, white fish or fishcakes.
• Use on chips, wedges or roast potatoes.
• Add to sweetcorn with butter.
• Mix into mayonnaise for a quick seafood dip.
• Season chicken wings or cauliflower bites before roasting.

Simple Old Bay-style substitute

For a rough homemade version, mix celery salt, paprika, black pepper, mustard powder, a pinch of cayenne and a little ground bay leaf if you have it. It will not be identical, but it gives a similar savoury-spiced feel.

Omam

Omam is a Tamil name for ajwain, also called carom seed. The small seeds have a strong thyme-like aroma because they contain thymol. They taste pungent, peppery and slightly bitter.

Omam is common in Indian cooking, especially in savoury snacks, breads, lentil dishes and digestive-style spice preparations.

How to cook with omam

• Add a pinch to pakora or bhaji batter.
• Use in paratha or flatbread dough.
• Temper in hot oil with cumin and mustard seeds.
• Add sparingly to lentil dishes and potato curries.

It is powerful, so use less than you think. If a recipe asks for ajwain and you only know it as omam, it is the same spice.

Oriental Mustard Seed

Oriental mustard seed usually refers to brown mustard seed, commonly used in Indian, Chinese and other Asian cuisines. It has a sharper, hotter flavour than yellow mustard seed.

The seeds can be used whole, crushed or ground. When fried in oil, they pop and release a nutty, mustardy flavour.

How to use oriental mustard seed

• Temper in oil for dals, curries and vegetable dishes.
• Add to pickling vinegar.
• Crush into homemade mustard.
• Use in spice blends with cumin, coriander and fenugreek.

Keep a lid nearby when frying mustard seeds, as they can jump from the pan as they pop.

Olida

Olida, also called forestberry herb or native cinnamon myrtle, is an Australian native spice leaf with a warm, cinnamon-like flavour. It is not a standard UK supermarket ingredient, but specialist spice shops may stock it dried and ground.

It can be used in sweet and savoury dishes where you might use cinnamon, bay or warm baking spices.

Ideas for using olida

• Add a small pinch to biscuits or fruit crumbles.
• Use in spice rubs for pork or roasted squash.
• Infuse in warm milk for desserts.
• Add to chutneys, relishes and barbecue sauces.

Because it is less common and can be pricey, treat olida as a special-occasion spice rather than an everyday cupboard item.

Opal Basil

Opal basil is a purple basil variety with glossy dark leaves. It tastes similar to sweet basil, with peppery, clove-like notes. It is a herb rather than a spice and looks lovely in salads and garnishes.

Use it fresh where possible, as the colour and aroma are best before drying.

How to use opal basil

• Tear into tomato salads.
• Blend into pesto, alone or mixed with green basil.
• Use as a garnish for soups and pasta.
• Stir into herb butter or flavoured oil.
• Add to sandwiches with mozzarella or grilled vegetables.

If you grow herbs on a windowsill, opal basil is a good choice for adding colour as well as flavour.

Olive Herb

Olive herb is the common name for a herb with a savoury flavour reminiscent of olives. It is sometimes linked with santolina varieties and is used more often in herb gardens than supermarket cooking.

The leaves can be used fresh in small amounts, particularly in Mediterranean-style dishes.

How to use olive herb

• Chop into tomato and cucumber salads.
• Add to roast vegetables near the end of cooking.
• Use in marinades with lemon, garlic and olive oil.
• Mix into soft cheese or yoghurt dips.

It is quite distinctive, so try it as a garnish first before adding larger quantities to a dish.

Easy Substitutes for O Herbs and Spices

If you are trying to avoid an extra supermarket trip, these swaps can help.

How to Store Herbs and Spices That Start With O

Most dried herbs and spices last longest when kept away from heat, light and moisture. A cupboard away from the oven is better than a rack above the hob.

• Use airtight jars: Moisture makes powders clump and can spoil dried ingredients.
• Label refill bags: Add the purchase date so you know what needs using first.
• Do the sniff test: If oregano, orange peel or onion powder has little aroma, the flavour will be weak.
• Buy what you use: Large packs are only a bargain if you can get through them before the flavour fades.
• Keep fresh herbs chilled: Fresh opal basil is delicate and best used quickly.

Cheap Meal Ideas Using O Herbs and Spices

These ingredients are useful for making budget meals taste less basic.

• Oregano tomato pasta: Simmer tinned tomatoes with garlic, oregano, salt, pepper and a pinch of sugar.
• Onion powder wedges: Toss potato wedges with oil, onion powder, paprika and salt, then roast until crisp.
• Orange peel porridge: Add a little orange zest or dried orange peel with cinnamon and raisins.
• Omam flatbreads: Add a pinch of omam to simple flour-and-yoghurt flatbreads.
• Old Bay-style mayo: Stir seasoning into mayonnaise for fish finger sandwiches or potato wedges.
• Mustard seed potatoes: Fry boiled potatoes with mustard seeds, turmeric and onion for a cheap side dish.

FAQs About Herbs and Spices That Start With O

What is the most common herb that starts with O?

Oregano is the most common herb that starts with O. It is widely used in Mediterranean, Mexican and everyday home cooking, especially in pizza, pasta sauces and roasted vegetable dishes.

Is onion powder a spice?

Onion powder is usually classed as a seasoning or spice cupboard ingredient. It is made from dried, ground onion and is used to add savoury flavour to rubs, sauces, soups and snacks.

Are onion seeds really from onions?

In many UK shops, onion seeds are actually nigella seeds, also known as kalonji or black onion seed. They are not usually true onion seeds, but the name is commonly used on packaging.

What spice starts with O and tastes like thyme?

Omam, also known as ajwain or carom seed, has a strong thyme-like aroma. It is commonly used in Indian cooking, especially in breads, snacks and lentil dishes.

Can I make my own dried orange peel?

Yes. Wash the orange, remove thin strips of peel and dry them fully in a very low oven or dehydrator. Store only when completely dry and brittle, in an airtight jar.

What can I use instead of oregano?

Marjoram is the closest substitute for oregano, though it is milder. Thyme, basil or mixed Italian herbs can also work depending on the dish.

Which O herbs and spices are best for budget cooking?

Oregano, onion powder, onion flakes, orange zest and mustard seeds are especially useful for budget cooking. They are affordable, last well when stored properly and can add plenty of flavour to simple ingredients.