how to grow broccoli indoors

Grow Broccoli Indoors (Container, Hydroponics, From Scraps)

Want an edible houseplant? Broccoli is a relatively easy plant to grow, if you have the space. The benefits are you’ll have a fresh vegetable year-round or in your apartment, plus a living green conversation piece in the meantime, not to mention on-demand microgreens for your morning smoothies. Load up on the sulforaphane and other bioactives present in broccoli that provide positive physiological effects.

We’ll cover the basics of how to grow broccoli indoors: how and when to plant it, which varieties of seed to choose for indoor living, and how to harvest broccoli you’ve grown indoors in containers.

What You Need to Grow Broccoli From Seed

Starting your indoor garden with store-bought broccoli transplants can be a great way to begin with confidence, but it is a real joy to grow your plants from seed. 

Growing broccoli doesn’t require much in the way of materials, but before you get started, you need to decide how you want to grow the vegetable.

To grow broccoli indoors from seed, you need:

  • Broccoli seeds. Choose from fast-maturing broccoli varieties. Recommended fast-growing cultivars are Atlantic, De Cicco, or Waltham #29. You’ll harvest full-size broccoli heads in as little as 50-65 days from sprouting! 
  • Large-sized pots. One 3- or 5-gallon pot per plant.
  • Potting soil. A high-quality potting mix with good drainage properties, plus some homemade or trusted store-acquired compost, mixed 1:1.
  • Decent amount of light. At least 6 hours of sunlight a day, or some grow lights. Your container broccoli garden can even do well with as little as 6 hours of sunlight which is far less than some other large vegetables.
  • Cooler temperatures indoors make your broccoli happiest.

Want to Plant the Seedlings Outside Instead? No Problem

If you’ve planted your seeds in early spring and decide to transplant your baby broccoli seedlings into an outdoor garden bed, you need even fewer materials. You can start the seeds directly in the soil or choose to grow them in those little peat pots first, and then transfer them to your home garden.

How to Plant Broccoli From Seed

If your goal is to get a head-start on the growing season, start germinating broccoli seeds indoors a month or two before your zone’s typical last frost. Grow these seedlings indoors for 6 weeks, then transplant them into an outdoor container, two or three weeks before the average last frost.

Fill seedling cups with potting soil. Plant two broccoli seeds per container at a depth of a quarter- to a half-inch deep. Cover and water thoroughly. Place in a warm area and keep the soil moist, but well-drained.

The seeds should germinate within 5 to 10 days. Place your wee seedlings in a well-lit area. A west- or south-facing windowsill is great, or place under artificial grow lighting for a minimum of six hours each day. If both seeds in a container sprouted, cut out the smaller of the two. (I always feel bad doing this, but the whole point of planting two seeds is to ensure at least one will sprout.)

Baby them for the next month, making sure the soil is kept evenly moist, and that each seedling gets to soak in at least six to eight hours of light each day.

But you’re here to learn how to grow broccoli inside your house, either hydroponically or from seed in potting soil, so let’s continue.

Growing Broccoli Indoors Under Lights

Growing broccoli indoors: doable.

This video covers how to set up a growing space for broccoli indoors under lights, which lights to choose, and where to place your veggies over the winter months.

Basic Broccoli Necessities

Large Containers for Growing Broccoli

Broccoli is perfectly happy to live in a pot. Broccoli is a large-leaved and heavier feeding vegetable crop, however, so pick a container size of 3 to 5 gallons per broccoli plant you grow; broccoli leaves do have a very wide spread from the stalk, so plant only one per 5-gallon container. You can fit two to three plants in a 15-gallon container. Keep in mind that broccoli will take up a lot of your indoor growing space, and proceed accordingly.

Potting Soil

As a heavy feeder, broccoli likes nutrition-packed potting soil; to appease its needs, make a 1:1 mix of quality potting mix with some homemade compost. Besides nutrition, broccoli also likes light, well-aerated soil that drains well. This is the key to keeping your broccoli plant happy indoors. No roots sitting in water!

Water. No Surprise Here

Give your broccoli soil 1 to 1.5 inches of water each week.

Fertilizer. No B.S.

If you have the right soil mix (1:1 basic potting mix and compost), skip the fertilizer. If you have low nutrient soil, try adding an all-purpose organic fertilizer that has the micro-nutrients boron and magnesium. For example, if you must, add a 10-10-10 (NPK) fertilizer, and follow the directions on the package. 

Sunlight. No Kidding

Although broccoli is a larger and fast-growing vegetable crop, its need for direct sunlight is a little less than many other similar-sized plants. Shade tolerant to a certain degree, broccoli plants will thrive with a minimum of 6 hours of direct sunlight daily.

Comfortable Room Temperature

Broccoli tends to bolt (flower) when the temperature strays above 75 degrees Fahrenheit, and once broccoli bolts, its harvesting period is over. To encourage your broccoli plants to produce for a long time, have a space in your home that mimics the cooler temperatures of spring and autumn.

Considerations When Growing Broccoli Indoors and Moving Plants Outdoors in Pots

If you’re planting in autumn, start your seeds about one month before the first average frost. Either plant them directly in your container or start them indoors broccoli seeds germinate at 75-80 degrees Fahrenheit (23-27 degrees Celsius) and may not sprout outdoors if temperatures are beyond that range. If you’ve started them indoors, harden off your seedlings by setting them outside a few hours per day for two weeks before moving them outside permanently.

After Germination

Even after germination, pay attention to the temperature; containers, especially black ones, absorb a lot of heat from sunshine. Keep your broccoli container temperature below 80 degrees Fahrenheit (27 degrees Celsius). Avoid dark or black-coloured containers, and strategically position your plants so the broccoli plant is in partial shade and the container is completely shaded.

How To Grow Broccoli From Stalk Scraps

If you buy a bunch of broccoli from the store and end up with a nice stalk after cutting off all the florets, why not try to grow some more green goodness?

Place the stalk in a jar with a few inches of filtered water, and place the jar in a sunny or partly shaded location. Replace the water every other day, just to keep things fresh. Soon, new roots will form along the stems. When the roots grow to about 2 inches in length, plant the individual stems in a larger pot.

The broccoli plant has shallow roots so be sure to stake your plant as it grows, to keep it standing tall.

How to Save Leggy Broccoli Seedlings

What can you do to fix leggy seedlings? If you start seedlings indoors, low light levels can cause them to stretch towards the light and have a pale or yellow colour. Warm temperatures, high humidity and poor air circulation can also lead to limp, weak plants.

So, to fix you leggy broccoli seedlings, place them in a cooler, less humid room with good air circulation and better lighting.

Harvesting: How Long Does Broccoli Take to Mature? 

Broccoli grown from seed will be ready to harvest in 100 to 150 days. Grown from transplants broccoli will come to harvest in 55 to 80 days. Did you know the broccoli leaves are edible? Prepare them as you would chard or kale: by steaming or chopping up finely into a mixed greens salad. Cut broccoli buds while they are still green and tightly packed. Cut off the central head and include the top five to six inches of stem. 

Broccoli Soil VS Hydroponics: Growing Broccoli Microgreens