Growing sage indoors (method, care & harvest)

Sage (Salvia officinalis) is a member of the mint family of herbs and is a great perennial herb to grow indoors. It’s easy to care for and has a lot of uses in the kitchen. This article will cover what you need to know about growing sage indoors, focusing on methods, plant care, and harvest.

Whether you’re just starting with herb gardening or looking for a new herb to add to your indoor garden, sage is a great choice!

Sage leaf with its characteristic textured surface
Sage leaf with its characteristic look

Today we focus on the common garden sage, also known as golden sage or “Salvia officinalis”, even though purple sage is one of our favorites. There are also dwarf varieties, as the common sage can grow as tall as 60 centimeters (24 inches tall).

Growing sage indoors is not necessarily tricky. But it does require patience as sage grows slower than herbs like basil and coriander (cilantro).

Growing sage indoors requires well-drained soil and placing the plant in a location with full sun. Remember that sage is a Mediterranean herb that, much like rosemary, tarragon, thyme, and oregano, needs proper drainage to ensure the roots do not sit in wet soil. 

5 steps to growing sage indoors

1. Select pot and soil

Plastic pots with drainage holes will help you maintain a moist growing environment for the seeds.

I recommend using a good-quality potting mix. We use a 50/50 mixture of potting soil and cactus potting mix. 

The Cactus potting soil helps create a fast-draining, low-fertile growing environment for the delicate seeds and seed roots as they germinate. 

The regular potting mix in the bottom half of the pot will provide the seedling with nutrition later on as the root system starts to develop.

For optimal growth, fill the bottom of the pot with a well-draining material like stones or LECA pellets to reduce the risk of root rot.

2. Plant the seeds

Scatter the seeds superficially over the potting mix and then press lightly to ensure contact between seed and soil.

The seeds need light to germinate, so you should not cover them. Placing the pots in a sunny window should work even if you are planting in early spring.

I leave my seeds uncovered in the pots and find that using plastic pots helps avoid dry outs.  

You can cover the pot with plastic to help keep the seeds moist. Make sure to add holes in the plastic to ensure proper air circulation. If you see condensation inside the plastic, you must improve air circulation.

Sage seeds take approximately 2-3 weeks to germinate, which is where patience comes into play.

You do not need to soak the seeds before planting but soaking the seeds can reduce germination time significantly.

If you are planting in early spring, you may need to use plant- or grow lamps to help the seeds and seedlings develop during the darker times of the year.

3. Water your seeds and seedlings

Keep soil moist when seeds are germinating. Bottom watering is the easiest way to water your pots to avoid disturbing the seeds.

As the seeds germinate, you can top water if you avoid getting the sage leaves wet.

I prefer bottom watering as it helps the soil retain the moisture it needs without risking overwatering.

You will know when to remove the pot as the color of the soil turns darker.

Bottom watering pots
The soil turns dark as it gets moist.

4. Natural light vs. grow light

Sage seeds need light to germinate. Growing indoors, you need to ensure that you are providing enough hours of sunlight. And if not, you should use grow lights.

Your seeds need a minimum of 6 hours of sunlight; if you use a grow light, you should double the hours required.

5. Young sage plants need moisture

Keep the soil moist and ensure that the plant gets enough light as the seeds develop into seedlings and young plants.

Whereas an established plant is a drought-tolerant and hardy herb, young plants and seedlings need water to develop new roots.

Bottom watering is preferred as it does not compact the soil and helps maintain a well-draining structure.

Plant care

By providing a few basic things: watering, temperature control, and some direct sunlight daily, you’ll soon have plenty of herbs to begin harvesting fresh sprigs for your cooking.

Be careful, however, not to overwater. Feel the soil by inserting your finger about 3cm (1 inch) into the soil. If it feels moist, then your sage does not need watering. It is better to have slightly dry than wet soil. A plant that’s been appropriately watered will have deep green leaves and resist wilting.

Harvest your sage regularly. This encourages new growth and helps keep fungal diseases at bay by ensuring plenty of room for good air circulation.

Sage plants in need of harvest
Sage plants in need of harvest for improved air circulation

Use herb scissors and snip the sage leaf off its stalk. You will see small nodules where new leaves are forming. Harvesting your sage regularly as the leaves become big enough allows the sun to get to the fresh lower leaves that are starting to grow. Newer leaves will have the most flavor, so try to harvest them when they’re young, but of course, only harvest leaves that you will use.

Sage harvested before bloom retains the most flavor and can be stored fresh in a refrigerator for up to two weeks.

Light is essential to sage plants

Sage has its origins in the Mediterranean. It needs and likes light and warmth. Plants should be placed where they get at least six hours of sun each day.

Grow light is needed if not enough natural light
The grow light we use for sage indoors.

If you’re growing your sage plant indoors, you can place it near a south-facing window. If there is not enough natural light, you should use grow light to help your plants grow and develop during the darker times of the year.

Watering your sage plant

Sage likes a well-drained, moist growing environment but prefers a mild dry out to over-watering. Sage is quite a drought tolerant when established, and sage plants prefer to almost dry out between watering.

If you wonder if your sage plant is established, look for the telltale woody stems that the mature plant develops.

To keep the soil moist does not mean that the surface must be wet at all times. Quite the contrary. Sage plants do not like their roots to be soaked in constant wetness.

Insert your finger into the pot, and if the soil is dry two knuckles deep, it is time to water your plants. We use water moisture meters that are inexpensive to buy as they help eliminate any uncertainty.

Pests and diseases

Growing indoors, you are spared many problems you could face in an outdoor garden.

Sage can suffer from a fungal disease, and it’s essential to check for telltale signs during the growing season to avoid losing your plant altogether.

If you see small white powdery spots appearing on the leaves, take quick action, as this fungal disease called powdery mildew can kill your herb as it feeds off the plant. Do the following:

  • Ensure your plant has enough light. If it does not, then move it to a new location.
  • Check that it is not touching any other plants. Trim leaves back if it is.
  • Use neem oil to treat the leaves. This leaves little residue and means that your sage will still be safe to eat.

To help health, try companion planting. These are plants that grow well with sage and are mutually beneficial to each other. Good companion plants include lavender, rosemary, and thyme. Sage will also be happy growing close to carrots and beans.

Harvest sage leaves

There is one golden rule regarding harvesting sage: Never cut back more than half the plant and, ideally, less than a third.

If you harvest or cut back your plants too aggressively, you risk hurting new growth, and the plant may stagnate.

Also, harvesting leaves will encourage growth and help the plant thrive and become bushy. New leaves have the most flavor, but it can be wise to harvest from the outside and in. And continuous harvesting is preferred to occasional bulk harvesting.

Sage is best used fresh or dried. To dry sage, cut sprigs with sharp scissors and hang them upside down in a dark room with good air circulation.

Sage is one of the classic culinary herbs

Sage is a classic culinary herb almost instantly recognized by most. The light green to grey leaves have a fuzzy, textured exterior, and the strong aroma and flavor make it a favorite for creamy pasta, robust meats, and poultry dishes. Add herb cocktails and sage tea to the list, and it is easy to understand why the herb is a favorite among chefs and food lovers.

As the flavor is robust, the herb should be added early in the cooking process to balance the flavor profile.

Grow sage indoors from stem cuttings

Using a sprig or a stem cutting, you can also propagate sage from an established main plant. There are many ways to get stem cuttings to propagate new plants.

  • Buy a plant from a grocery store or local garden center
  • Prune, and use sprigs from your plants
  • Ask a friend or fellow gardener for a cutting

Please read our article How to grow sage from cuttings for a step-by-step guide on how to start growing sage indoors without using rooting hormones.

Meet the author: Mattias is an experienced gardener spending most of his free time on his knees among herbs, plants, and garden vegetables. For the past two years, he has been sharing gardening projects and how-to tutorials on the NordicLavender website and YouTube channel.