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GROW BASIL INDOORS

Basil Basics

Before you start growing indoors, learn the basics about type, temperature, and light. 
If the basics are doable for you, then follow the step-by-step directions that are further down the page.

Type

All varieties can grow indoors, but choose a compact variety like Spicy Globe for tight spaces or a weaker light source.

Temperature

Basil needs a growing place that is above 70°F and away from drafty windows for those in cold climates.

Light

Basil does great with a grow light or next to a south or west-facing window with 8+ hours of strong sunlight.

Step-By-Step Directions

Step #1 Prep

Seeds

Choose a smaller basil variety if you have limited space and/or don't have grow lights. If these are not issues, feel free to throw in whatever basil seeds you may have. Smaller Varieties include Spicy Globe, Greek, Boxwood, Dwarf Bush, and Holy. 

You can also grow basil by taking a cutting from an existing plant. Learn more about that in step #2.

Soil

You'll need "Indoor Potting Soil/Mix" or "Seed Starting Soil/Mix" to start your indoor basil. It's important to purchase an indoor-specific soil from a place that has kept the soil indoors as well. Indoor storage reduces the chance of bringing in unwanted house guests (aka bugs). If you use "Seed Starting Mix" then you'll want to first plant in a tiny container/pot and then transplant the seedling into a new pot filled with moistened potting mix when you thin (step #7).

Container

Most herbs like an 8-10" pot/container to grow in. That size of pot enables you to keep the plant for a full indoor season (or longer) without restricting the growth of the plant or needing to "pot up" (move into a bigger pot). However, some plants do just fine in smaller pots (4" and 6" pots). You can also use a bigger pot, but put an extra (or 2) plants in so that you aren't wasting planting space. 

No matter the pot size you choose, make sure it has drainage holes and you have a plate/saucer beneath it. 

Whenever possible, I actually prefer smaller size pots (4-6") if growing near windows. Basil is one of these, particularly because I plant several during the cold months to allow for different varieties. When I feel a plant is suffering from the small pot size, then I harvest the full plant and compost the soil and remaining plant pieces.

Other

You may also want a grow light, spray bottle, watering can, sharp scissors, and fertilizer. More on those items below. 

Step #2 Plant

From Seed

Fill 3/4 of your pot with moistened soil. Place 3 seeds near the middle of your pot. Sprinkle a tiny bit of soil over the top, don't worry if the seeds are totally covered.

Optional Step: Cover your container with a see-through glass or plastic cover/wrap at this point to create a warmer and more humid environment for your seeds. This may speed up germination and reduce the need to mist the soil with water (Step #3).

Covered or not, place in a non-drafty space above 70°F. Basil seeds need moist soil and warmth to germinate. Light isn't necessary.

From Cutting

Take a 4-inch stem cutting right below a node and remove all of the leaves from the bottom 2 inches of the stem. See the image below to find the node.

Place the cut end in a jar of water and put the jar next to your best growing window or under your grow light (see step #4). Change out the water daily.

You can plant your new plant when the roots are a few inches long. Just dig a 1/2 inch hole in the middle of your pot with moistened soil, place the plant in the hole root side down, and then surround with soil so it stands up straight and strong. You can now head to step #6.  

Step #3 Mist

Your fragile seeds don't want to be knocked around when they're trying to grow. To avoid disturbing them, use a spray bottle to mist them with water. 

Mist them daily to keep the soil moist. You may need to mist in the morning and night if the soil seems dry.

Don't have a spray bottle? Dribble water on the soil close to your seeds by dipping your fingers in a cup of water and shaking off the water over your pot.

Step #4 Wait

Basil seeds are fairly quick to germinate, usually 3-5 days. 

If you don't have a clear cover on them, mist the seeds and soil with water daily to keep the soil moist. If you have a cover on your seeds, peek in daily to make sure the soil is still moist.

Once your little plants erupt, remove any clear covering you may have had on them.

Troubleshoot: If no leaves appear after 10 days, consider starting a new pot. Check the dates of your seeds and soil to make sure they're still healthy. Consider putting your next pot of seeds on top of the fridge for some extra warmth (just don't forget they're up there!).

Step #5 Water

Basil likes well-drained soil that is moist, but never soggy. It doesn't survive droughts, so you'll need to keep it hydrated. There are two common methods for indoor watering: Top watering and bottom watering.

Top Watering

Top watering is the usual watering method. You'll simply water the soil near the main stem of the plant. Use a watering can that has small holes or continue to mist until your plant can handle the pour of a bigger watering can or jar.

Bottom Watering

Bottom watering just means placing water in the saucer/drip pan under the pot (rather than watering the soil from the top). The roots suck up the water through the soil. Some growers do this from the very beginning.

Bottom watering can help deter insects and help the plant grow even more stable and strong. That's a really good thing for top-heavy plants (like tomatoes or peppers). If bottom watering, it's also helpful to flush the plant monthly by top watering to soak. Dump out any water that flows into the saucer. Not sure about watering from the bottom quite yet? No worries! Water from the top.

Step #6 Light

Now it's time to feed your plants the light they need to grow.

South or West-Facing Window

Basil can grow well next to a non-drafty window that gets at least 8 hours of sun. Rotate your plant every few days for even exposure. You'll know if your window isn't doing the job. Your basil plant will get tall and weak, with few leaves. If that happens, try a different window or a grow light.

Grow Lights

  • Standard Fluorescent: Keep this light about 2 inches from the top of your basil and keep on basil for 16-18 hours.
  • Compact Fluorescent: Keep about 1 foot from the top of your basil and keep on for 14-16 hours.
  • LED: Keep about 1-2 feet from top of basil and keep on for 10-16 hours.

Rotate your plant every couple of days or so to get even light exposure. Your plants will also tell you if the lights are too close or too far away:

  • Too close: Leaves will get burned and look brown/yellow.
  • Too far: Tall, weak-looking plants that are growing slow. 

Step #7 Thin

If you have more than one seedling, then you'll need to thin or move your plants. Do this when your seedlings are a few inches tall.

If your pot is 10-12", you can keep 2-3 seedlings in the pot, spaced out in a line or triangle shape (this could be 2-3 basil plants or mix it up with a different herb). Just gently move the seedling(s) with a spoon, digging enough dirt to place them back in the soil as they were before. If you have a larger pot

If you have a smaller pot, then stick with one seedling. Choose the best one and remove or repot the rest. 

Step #8 Prune

A bit of pruning can make your plant healthier, fuller, and more round rather than tall and wobbly. 

Begin pruning when your basil is about 6" tall or you start seeing flowers. With a sharp scissors or garden snipper, clip the stem a bit above a node, keeping at least 3 inches of base stem or half the stem length in tact. Basil is forgiving, but don't prune away too much. 

Continue to snip off the top in this manner throughout your basil's life to encourage a more compact and productive plant.

Step #9 Fertilize

Basil likes nutrient rich soil. Dependent on your soil, you may need to add organic fertilizer. Some soil mixes provide enough nutrients for several months, so check the bag.

If you're reusing indoor soil (which you should do!), then you'll likely need to fertilize 4 weeks after germination. Signs of needing fertilizer include dull colored leaves and flavor and noticeably stunted growth.

Just a 1/2 dose of an organic fertilizer is usually enough (I like seaweed based fertilizers). An organic, plant-based fertilizer is generally simple to use and is more forgiving of mistakes. Start with less and build up as needed.

You can also test your soil for nutrient levels and fertilize more precisely based on what your soil needs more of. If you're a pH checker, aim for soil between 6 and 7.5.

Step #10 Harvest

You'll have some basil to enjoy about 6 weeks after germination or when it's 6-8" tall. And, the more you pick, the more returns. Try to harvest in the morning to limit stress to your plant and before flowers form for best leaf flavor. But don't despair if flowers appear. They are edible and you can clean up the plant quickly (see directions below for overgrown plants).

If your plant is not overgrown:

  • Pluck a few of the largest leaves or
  • If you want more:
    • Using clean, sharp scissors or even your fingernails, snip or cut off stems right above the node where a pair of leaves originates.
    • Do not leave a stub of the stem on the plant.

If plants are overgrown (buds/flowers are forming or it's getting too big):

  • Start from the top of the plant and work your way down, harvesting about 1/2 the length of the stems.
  • Don't harvest more than 2/3 of the plant at one time.
  • Give the plant some days to rest after a heavy harvest.