Tips for Growing Herbs Indoors

John R. Shaffer
Adams County Master Gardener

I love to consume herbs that I have gown myself. Not only do my meals reach a new plateau, but I gain immense satisfaction knowing I grew the regale enhancing ingredients myself. Ah, but alas, autumn signals the end of homegrown herbs, tomatoes and bouquets of blooms. However, it doesn't necessarily mean I can't continue to grow my prized herbs. I merely have to move the process indoors.

The art of growing herbs indoors eluded me for many an autumn moon, but I eventually defeated the winter weather demons. A heap of persistence and a dash of fortitude paid off and I have since managed to maintain a fair bounty of indoor home grown herbs throughout the winter months.

To my dismay, I have discovered that not all herbs will grow well indoors, but don’t let that dishearten you. There are many herbs that can be fooled into thinking that the summer months are still upon us. For the faint at heart, start out with my tried and true list of indoor friendly herbs. Some of my favorites are scented geranium, mint, rosemary, parsley, bay leaf, thyme, chives, garlic and oregano. Basil, dill and coriander should be started from seeds and mint, rosemary and bay leaf can be rooted from cuttings.

Basil is fairly difficult to grow indoors because, just like me, it is a lover of sun and heat. It can be done though if you can provide the plants with 16 hours of artificial light and daytime temperatures of 65 to 75 degrees F and nighttime temperatures that do not drop below 50 degrees F.

If you are starting with seedlings purchased at a nursery, it is important to acclimate them to the lower light conditions. New leaves that are accustomed to the lower light conditions must be produced for the plant to survive. Be sure to give yourself plenty of time to complete this process. This adjustment period can mean the difference between a healthy herb and one that loses it leaves, becomes leggy or even dries up and dies.

A windowsill with southern exposure is often all you need to grow herbs indoors. Most herbs require at least 6 hours of direct sunlight and it doesn't hurt to put them under a grow light. The exceptions to this rule are mint, parsley and rosemary, which can take a little less light. With this mind, place the sun lovers in the center of the windowsill and those that need less light on the outside edges. If you use a grow light, be sure the lights are about six to nine inches above the tops of the plants. Your herbs will prefer temperatures between 55 and 70 degrees F.

It is important that your potted herbs have proper drainage. I use a mixture of 1 part good quality potting soil, 1 part sand and 1 part humus. Towards the end of winter you may find that the soil in the containers has become compacted. Simply rake the surface with a fork to loosen it up. During the winter, plant growth slows so they don't require as much water. The rule of thumb is to only water when the soil surface is dry. Herbs such as bay leaf, thyme, oregano and sage should dry out completely between watering while mint, rosemary and scented geranium prefer a little more moisture.

Unlike herbs that grow in the garden, potted herbs need regular feedings. Fertilize with a fish emulsion at half strength about once a month. To help herbs survive the stuffy air typical in our homes during winter mist the plants, especially rosemary, on occasion and increase air circulation around them with a small fan. Keep in mind a fan may cause the soil to dry out faster, requiring you to water more frequently.

Pest are usually much easier to contend with indoors. If you have a problem with pests, I recommend you use an insecticidal soap. Saturate the tops and undersides of leaves. Insecticidal soap is effective and safe. And this is something to keep in mind if you're planning on using these to spice up some of your favorite recipes.

So now you do not have an excuse for creating bland meals during the colder months of the year. Get growing and bon appetite.

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