How to Grow Arugula Indoors

To set one up:

1. Fill up the planter with dry soil from the bag, gently tamping down the top.
2. Dump the soil into a large mixing bowl and add water until the soil is moist, but not sopping wet (about ½ Cup)
3. Mix in 1 tablespoon of the Balanced Blend Plant Food.

If you are using a regular pot instead, it should be a little bit bigger (at least 6″ / 1 quart and will need drainage holes to prevent it from being over watered. Let the top of the soil dry out between watering.

Starting your Arugula: Seed vs Propagate vs Live

New Arugula plants can be started from seed (preferred), propagated from an established plant, or purchased live at many garden centers. We like starting from seed the best because it’s quicker than propagating from a cutting, less expensive than using live starters, has tons of options, and there’s no way unexpected visitors (pests!) are riding along.

How to Plant Arugula seeds indoors

Growing arugula indoors from seed is fairly easy. Plant 2 sites in a 6″ / 1 quart container. In larger containers, space sites 3″ apart. For each site plant 2 seeds 1/4 inches deep. Keep the soil warm ( 40-90°F, ideally 60°F). Sprouts typically appear in 7 days but can be as quick as 5 days or as long as 10 days depending on your conditions.

How to Transplant Arugula

1. Remove some soil from its final planter – leaving enough space for the bottom of the seedling to be just higher than the soil surface.
2. Hold on to the base of the stem with one hand, and turn the pot over while gently pulling the seedling. Giving the pot a few squeezes can help dislodge it.
3. Place in its final container and fill around it with soil so that it’s tight, but not compacted.
   

   Where to grow your Arugula plants

   Like all edible plants, Arugula plants need lots of light to grow and develop good flavor. Sunlight is excellent for plant growth (and free!) and you might be lucky enough to have a spot that’s got the 5+ hours of direct sun they need. Even with a bright window, it’s unlikely that you’ll have enough natural light in the winter so we recommend a grow light for anyone who wants a constant supply of flavorful produce. For an introduction to grow lights, head over to our post on grow lights for indoor gardeners. We’ve also got a buying guide for screw in types, but to keep things simple in this guide, we’ll just provide directions for the 24W Screw in Bulb by Sansi, which we think is a good middle of the road option.

How bright should your grow light be? 

Arugula plants need the equivalent of 5+ hours of direct sunlight [DLI of 15+ mol/m²/day] to grow their best. In order to provide an equivalent amount with a grow light, it needs to be pretty bright! The 24W Sansi bulb should be placed 6 inches away from the top of the plant. This will give your PPFD (the standard measure of brightness) of 500 μmol/m²/s.

How many hours per day do your Arugula plants need under a grow light?

Arugula plants are known as “long-day”. When they sense over 12 hours of light per day, they’ll start the end of their lifecycle and work on making seeds. We want to keep them in an earlier stage so we can keep harvesting the leaves, so we recommend setting up a timer to leave it on for only 10 hours per day.

Extend your harvest by keeping the Temperatures Cool

Arugula is known as a “cool weather crop.” If it senses warming temperatures it will “bolt” – send up flowers and become bitter in the process. Where you plant them can have some effect on the temperature – lower positions on a growing rack, ceramic planters, and hydroponics with air bubblers tend to run cooler. It’s best to avoid windows that get really hot (like bay windows)

Week 1-2: Check for Sprouts

You could see seedlings in as little as 5 days (though 7 days is more typical). If it’s been 10 days and you still don’t have any sprouts, it’s likely that your setup is too cold.

Week 2: Check Your Seedlings

There’s no need to thin Arugula, but you should check on your seedlings’ progress to make sure you’ve got enough light. They should be about 1 inch tall by the end of Week 2. If they aren’t you likely need a bit more light.

Week 5: How to Prune Arugula

You’ll notice how all the stems and leaves of Arugula grow from a single, central point (called radial growth). The plant puts out new leaves in the center and pushes old leaves outward, getting bigger and bushier over time. Pruning and harvesting is one-in-the-same with Arugula. Once the plant at least 3 separate stems coming from the base take one of the outside leaves and cut it close to the base (½” above is fine). It’s good to leave at least 2/3rds of the plant left to regrow.

Month 2+: How to Harvest Arugula

Just as you did with your first prune, pick the outer leaves as needed, always leaving at least 1/3rd of the plant left to regenerate.

Month 6+: End of Life

When Arugula reaches maturity, it becomes bitter tasting and produces little delicate white blossoms. Harvest and eat these tasty blossoms before taking your plant down and starting over.

Shop This Blog

The right supplies can take the guesswork out of caring for your plants especially your arugula indoors – and turn care from a daily to weekly routine. Through our grow tests, we’ve found these products to produce the best indoor Arugula (and also have simple maintenance).  Plants are adaptable and can grow in many different conditions, so they are by no means necessary if you already have other supplies.

Best Containers for Arugula: Ceramic Self Watering Planters

Plants thrive on consistent moisture but can suffer if they’re waterlogged. A semi-porous ceramic self regulates ideal conditions. Our favorite is the COSWIP planter. Runner up is XS Self Watering Planter by Wet Pot.

Best Soil for Arugula: Standard Potting Mix

Arugula likes a rich and moist root zone – so you are best off with a standard potting mix – we like this Organic Mix by Espoma. 

Best Nutrients for Arugula: Balanced Blend

Arugula likes nutrients that are equal parts nitrogen, phosphorus and potassium (with NPK numbers like 10-10-10). For a Balanced Blend we recommend: Balanced Blend: Dr Earth All Purpose

Best Light for Arugula: DIY or Soltech

There is a very small chance that you have the bright windows needed to grow these without a grow light. If you are looking for a higher end option – we love the Aspect Light by Soltech. For a more affordable option a DIY set up using a 24W Screw-in Bulb by Sansi with a Clamp Light and Mechanical Timer works well too.  Check out our complete guide on a DIY setup for less than $40 or our buying guide for screw in bulbs.