Growing an indoor herb garden - East Idaho News
In the Garden

Growing an indoor herb garden

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When it gets too cold outside, it is time to bring the garden indoors. An indoor herb garden can ensure you have fresh ingredients for your favorite dishes. Not all herbs will grow well indoors because their root systems become too big, but there are several herbs that you can grow indoors. Here are some things that will help you to be successful.


Most herbs require at least 6 hours of direct sunlight. All day sun is even better. The more intense the light, the more oils will develop within the glands of the foliage and stem. Oil creates stronger fragrances and seasonings. South facing windows are great locations, but if that does not work for you, artificial lights are an option. I suggest using LED grow lights to provide the light your herbs need. There are several types of LED grow lights available, but I would look to find one that produces blue, red, and far-red light.

herbs on window
Adobe stock photo

The blue light will increase chlorophyll production, the red and far-red light promotes growth and flowering useful in short-day situations. Hang lights 12 inches above herbs for the first two weeks, then raise them to 24 to 30 inches allowing for even dispersion of light across the canopy. Lights should overlap with each other to create an even spread of light over the growth space to ensure proper plant growth.


Most herbs need to have at least 65 to 70°F day and 55 to 60°F night temperatures. Some herbs can survive temperatures in the mid to low 40s. Remember the temperature next to windows is cooler than the center of the room. To help plants survive these cooler temperatures a plant propagation mat could be used to keep the soil temperature in the desirable range.


Most herbs require well drained soil. With indoor herb gardens I suggest using a potting mix that includes 1 part coconut coir or peat moss, 1 part compost, and 1 part perlite. Coconut coir is an organic base I like using because of its ability to create space needed for roots to properly take in air and water. It absorbs about 25% more moisture than peat moss. Peat moss is slightly more acidic than coconut coir, is light, creates air and water space in the potting mix. Compost holds water, is full of nutrients, helps enrich the soil with micro-organisms, and helps with oxygen exchange. Perlite is especially important in a potting mix as it provides structural support for plant roots. Perlite is full of tiny pores that help with drainage and hold oxygen for plant roots.


Pots can be made of many materials but must have holes in the bottom for drainage. Herbs grow best in higher humidity than most of our homes have in the winter. To help improve the humidity around the herbs group pots together. Consider setting containers in a pan of moist pebbles or spraying plants with a misting bottle of water. A fan can be used to provide air circulation. When roots start growing through the holes in the bottom of the container it is time to repot plants into a larger pot. You can repot herbs several times to accommodate new growth.

Water and Fertilizer

Herbs grown inside should never have their soil completely dry out. Water the potting mix when it starts to dry out. I use the fingernail test to determine when it needs to be watered. I stick my finger into the soil up to the end of my fingernail, if the soil is wet, I wait, if it is dry I water. Liquid fertilizer can be added every two weeks.


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