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How Long Will Basil Grow Indoors

Basil might be one of the easiest and most rewarding herbs to grow. It is a tropical plant that requires warm weather and sunny days to thrive. When summer is over, it won’t survive outdoors once temperatures drop. You may be considering growing it indoors to have fresh basil in the off-season and if so, wondering, how long will basil grow indoors?

With the best care and optimum indoor conditions, basil can be grown indoors for several months. Basil however should be transferred outdoors after six months.

Growing basil indoors

Six months is about the maximum amount of time basil will grow well indoors. Consider this outdoors; the plant only lives through the late spring and summer months into early fall. That’s only about five months.

Basil is an annual. Annual plants do all their growing within one year. It won’t regrow the following year. A new plant needs to be started. Some varieties of basil, such as Thai basil, have been reported to reemerge the following year after a mild winter.

Simply taking a basil plant inside after temperatures drop isn’t ideal. You may get a few more weeks out of it, but starting a new plant will ensure the longest indoor life possible. You can start your indoor basil two ways. If you currently have a basil plant or variety that you love, you can take a cutting and propagate it. The second is starting from seed at the end of summer.

Of course, you can always buy a young plant from a nursery if you can find one later in the season.

How to propagate basil

  1. Choose a basil plant to propagate. This would be your best-looking and best-performing plant. Try to avoid diseased plants. You’re essentially cloning your basil if you really want the best plant.
  2. Snip off a stem about 2 – 3 inches under the leaf node. The leaf node is the area where tiny new leaves are forming. Look at the main stem; two large leaves grow at regular spacing. In between the large leaf and the main stem, you’ll spot another set of smaller leaves growing. That is the leaf node.
  3. Cut off the lower leaves and leaf nodes. Leave a few leaves at the top. This will probably be 2-3 large leaves and a pair of nodes. Now you have your cutting.
  4. Place the cutting into water, covering the snipped areas but leaving the leaves above the water. In about a week, your cutting will sprout roots where you snipped off leaves. Ideally, you want at least two sets of nodes to double your chance of spouting roots. It also makes for a stronger plant. Voila! It is that easy to propagate basil.
  5. The plant you rooted cutting into the pot you wish it to grow.

How to start basil from seed

  1. Prepare seedling trays for sowing seeds. You may also plant them directly into the pot you wish to grow the basil.
  2. Place the seeds at the top of the soil and press them in slightly. You can cover it with a dusting of soil. Basil seeds are tiny, so do not weigh them down.
  3. Keep the seeds watered; they will sprout in about a week or two, depending on the variety and if they have received adequate warmth and water.

How to provide the best care and conditions for an indoor basil plant.

Soil – Basil doesn’t like heavy soils. Don’t use soil straight from your outside garden since you’ll be growing the basil in a container. A soil mix is best, so amend with soil with compost or get a quality potting mix.

Temperature – Basil is a tropical herb, so keep it in the warmest part of your home. A continuous temperature under 70F will begin to affect the plants. Avoid drafty areas. Basil also likes humidity. The most humid areas tend to be kitchens and bathrooms, but humidity can also be created by misting the plant with water at the warmest time of the day.

Light – If the warmest area in your home is also a sunny area, that’s even better! Basil needs at least 6 hours of sunlight every day. It’s understandable that as the seasons change, lots of sunlight will not always be possible. Basil plants tolerate grow lights quite well. It does not have to be one or the other. A combination of natural light supplemented with artificial light works too.

Nutrition – While basil likes fertile soil, it doesn’t need overly rich soils. Adding compost to soil should provide adequate nutrition, but if the plant looks pale and could use a pickup, a small amount of liquid fertilizer will do.

Watering – Keep the soil moist but not wet. Potted plants need more frequent watering. A good rule to follow is to water when the top layer of soil dries out. Ensure the container has drainage holes. Basil roots are susceptible to root rot from sitting in cold, wet soils.

Pruning

Pruning basil will significantly prolong its indoor lifespan. A regularly pruned plant will avoid going into a flowering mode which can alter the taste of the basil leaves. The plant will focus instead on growing new leaves. It will also improve the plant’s shape, giving it a fuller appearance. Prune your plant around the time you plan to consume the leaves. 

If you happen to prune when you don’t yet have use for the leaves, no fear, basil leaves can be frozen. Freezing does change the texture, but frozen leaves work great in pesto. While you should prune basil early, don’t prune the plant when it only has a handful of leaves. Pruning can also be done after the basil has flowers. The sooner you can get to pruning once this happens, the better.

How to prune basil

  1. Examine the upper part of the main stem.
  2. Cut the plant about half an inch above the leaf node using a cleaned cutting tool.
  3. Prune off any flowers.

Basil varieties for indoors

Consider growing basil varieties better suited to grow in containers and can tolerate growing under different conditions than outdoor basil. Ideally, choose a variety you enjoy that will fit your usage needs. If there isn’t particular basil you enjoy or are looking to try new varieties, see below.

Suggested basil varieties to grow indoors

Basils for cooking- Genovese, Nufar, Rutgers. 

These fast-growing basils also have large leaves and grow well in containers.

Basils for tea – Dark Opal, Spicy Bush, Sweet Thai

These basils are compact for container growing and have small leaves suitable for brewing tea.