Growing Herbs Indoors in Containers
Posted: May 16, 2016
There are plenty of options when it comes to choosing a suitable container. Containers are made from various materials such as, clay, plastic, wood, and metal. You can purchase them or even be creative and make your own. Be careful not to use containers that have previously held toxic chemicals. Pressure treated wood should not be used as it contains copper. Used containers should be washed and sterilized with a solution of 1 part bleach to 9 parts water. Make sure your container is large enough to support full-grown plants and that it has sufficient drainage at the bottom.
Once you have decided on a container, purchase a good quality potting soil. Soilless mixes work well because they are lightweight, sterile, drain well, and are less likely to compact. You can use mixes that contain peanut shells, composted bark, or even coir (25% or more). Coir is natural fiber made from the husk of coconuts. Do not use soil from your garden as it does not drain well and can compact. It may also contain weed seeds and disease pathogens.
Now it is time to decide on herbs for the containers. It is best to select herbs that are drought tolerant and are compact or trailing such as parsley, rosemary, tarragon, and basil. You can also combine herbs with annual flowers and vegetables that have similar water and light requirements.
The location of your container is very important because herbs require at least six hours of direct sunlight. A kitchen window with a southern exposure is ideal. If your window is close to the kitchen sink, then you will have quick access to fresh water. One of the advantages of containers is that they are portable. You can put them in other locations such as a sunny porch, doorstep, or deck. If you do not have access to a southern exposure, then try for a southwest or west location. It is also possible to grow herbs successfully using supplemental indoor lighting. Place herbs about 4 to 6 inches from two 40-watt cool white fluorescent bulbs for 14-16 hours a day. Room temperatures should be at least 65-70 degrees F during the day and 55-60 degrees F at night. Grow lights can also be used, but they tend to be expensive. If you wish to place your herbs outside during the spring and summer months, you must first acclimate them to the strong rays of the sun. Place them in a partially sunny location then slowly expose them to more sunlight every few days.
Don’t forget about water and fertilizer, but be aware that one of the most common problems with container herbs is overwatering and underwatering. Overwatering can cause root rot, fungal diseases, and even fungus gnats. Underwatering can cause the leaves to wilt and scorch. You will need to find that perfect balance.
Be sure to fertilize your plants well. One disadvantage to using soilless mixes is that they do not hold fertility very long. You should add a pelleted time-released fertilizer at planting and then reapply after 2 months. Water your herbs weekly with a water-soluble fertilizer and adhere to directions for proper amounts.
Here are some tips for a successful container herb garden:
- Check soil frequently to see if the plants need water.
- Use soilless potting mixes.
- Rotate your containers every few days to ensure that the entire plant receives light.
- Do not harvest more than 1/3 of your plant at one time.
- Use 1 inch of mulch on top of the soil to help conserve moisture.
- Penn State Master Gardener, Monroe County