Growing Broccoli from Seed – Tips on Starting Broccoli Indoors

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Growing broccoli from seed indoors gives you a jump start on its long growing season. This cool-weather crop is delicious raw or cooked and it starts readily from seed. Starting broccoli from seed is worth a try, especially if you’re planting other seeds as well.

It only takes a few moments to plant broccoli seeds. I’ve grown them a few times but have yet to actually make it to a harvest!

Broccoli seedlings in soil next to a "Broccoli" plant tag
Broccoli seedlings in soil next to a “Broccoli” plant tag in our 2023 garden

That’s on account of the dreaded cabbage white butterfly. My new trick is to hide a plant or two under plant covers so we can actually enjoy a broccoli harvest!

This year I am trying to grow broccoli under raised bed covers from Aldi. I am hopeful this will keep the pests at bay.

Growing Broccoli from Seed - Starting seeds indoors
Growing Broccoli from Seed – Here’s our young broccoli plant once we transplanted it in our 2020 container garden.

When to Start Broccoli Seeds Indoors

Get a jump start on your seed sowing by planting broccoli indoors. You can sow seeds for broccoli plants inside about 5 to 7 weeks ahead of the last frost date. You can also direct sow broccoli in your garden about 2 weeks before the expected last frost.

How to Plant Broccoli Seeds

Growing your own broccoli plants is a rewarding experience, particularly if you can avoid the cabbage worms.

When planting broccoli from seed, gather seed starting trays or egg cartons, potting mix, broccoli seeds, and a pen or marker to label your seeds.

(You can also direct sow broccoli – it is one of the beloved cold crops!)

Bag of broccoli seeds above a "Broccoli" plant tag in the garden
So many broccoli seeds ready for planting!

Planting Broccoli Seeds Step-by-Step

Learning how to plant broccoli seeds is easy! Once you have your materials, just follow these simple steps.

  1. Fill your seed starting trays most of the way with potting mix.
  2. Choose the broccoli varieties you plan to grow and take a few seeds out of the packets.
  3. Gently make small holes in each seed cell and plant 2 or 3 seeds each. Plant broccoli seeds about ½-inch deep.
  4. Label each cell with broccoli seeds accordingly.
  5. Water the seeds thoroughly.
  6. Place the seed try under grow lights when you are finished planting.
  7. Monitor the seed trays for signs of growth and water needs in the coming days and weeks.

Broccoli Growing Tips and Tricks

Here are a few tips that may make starting broccoli indoors even easier!

  • Keep grow lights close overhead of the seedlings. This helps prevent them from getting leggy.
  • Harden off broccoli seedlings before planting outdoors. Avoid giving your young broccoli plants sunburn by gradually introducing them to the outdoor elements and natural sunlight.
  • Plan ahead for some broccoli pest control. The green cabbage worms blend in almost perfectly with broccoli and other brassicas.
  • Try multiple plantings of broccoli. You can also grow a fall crop of broccoli. Start broccoli indoors in the mid to late summer for a second harvest later in the year.
Heads of Fresh Broccoli in a Pile
Lots of Fresh Broccoli from the garden would be amazing!


Plan to plant two to three broccoli seeds per seed cell. That way, if one is a dud and doesn’t germinate, you still have a shot with the other seeds. You can also thin seedlings later or try your luck at transplanting them.

Plant broccoli seeds about 1/2-inch deep. A little less or a little more is likely fine as well.

Start broccoli indoors about 6 to 8 weeks ahead of your area’s last frost date. Be sure to keep broccoli seedlings under grow lights so they don’t become leggy.

Seeds for Waltham 29 Broccoli and Broccoli Miranda in the soil of a raised garden bed
Seeds for Waltham 29 Broccoli and Broccoli Miranda in the soil of our raised garden bed

Join Us in Growing Broccoli from Seed!

Our family loves broccoli and I am truly hoping we can outwork the pests this year. Germinating broccoli seeds is the easy part – getting it to harvest time proved to be the most difficult for us.

Do you have any questions about starting broccoli from seed? Also feel free to share any great tips on growing this amazing and healthy vegetable.

We’d love to hear from you in the comments below! We always respond and love hearing from you guys.

Happy Gardening!

05.09.23 – Updated to add new broccoli seedling photos and featured image, and converted questions to FAQ with schema.

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