How To Grow Broccoli From Seeds

Step by step pictures on how to grow big broccoli heads from seeds starting indoors. This gives amount of days it takes and best tips. Learn how to start growing your own food from seeds!

Looking to start growing your own broccoli from seeds? This provides full directions on how to grow your own broccoli in the garden – from seed to harvest and everything in between. I’ll also provide a full calendar as I know sometimes it’s helpful to know how long it takes so you can plan your garden.

How long does broccoli take to grow?

Most broccoli seed packets will tell you that broccoli takes 50-75 days, but in my experience broccoli takes much longer than that when you’re growing it from seeds. On average our broccoli takes 120-140 days from planting seeds inside to picking it from the garden.

Why are the numbers so different? That’s a good question, but usually I don’t feel like seed companies take into account growing them from seed indoors, which most people do. When you start them inside it’s a slower process, and you also have to wait until your weather is safe to move them outdoors (we’ll talk about that later).

Some years, we’ve had to keep them growing indoors for multiple weeks extra just to make sure we’re moving them outside when the temperature is safe for them. Once they’re outside, again, the temperature comes into play. Is it too cold? Is is too hot?

Last year our broccoli took 133 days exactly from start to finish, even though our seed package says 50 days to maturity.

How to Grow Broccoli From Seeds

Here was our exact broccoli planting dates last year (2019). I document our plants every single year so we have a full calendar for reference. If you live in the Northeast, or NYC specifically, you can find my past seed calendars here for help in when to plan your own planting schedule.

January 19 – planted seeds indoors (spring garden planting for zone 7)
January 21 – seeds start breaking through the soil
February 5 – plants moved to bigger containers indoors
April 5 – planted the broccoli outside in the garden
May 31 – harvested the first broccoli head
June – continued picking the broccoli until mid June

More in detail on those dates:

January 19 – we planted the seeds indoors. The last couple years we’ve been growing “Blue Wind” broccoli which we find works best for our zone and produces bigger heads of broccoli.

Some people ask “Should I soak broccoli seeds before planting?” We never soak our broccoli seeds. The only plant that we presprout is sugar snap peas.

January 21 – the seeds start to pop through the soil.  Hey baby plants!  As you can see, we grow everything under grow lights and use heat mats for the best germination rates. 

February 5 – the plants have outgrown their little seed starter pots. Now they’ll move to bigger pots so their roots can grow larger.

We also add perlite on top of the plants to help with overall drainage and results in faster, stronger growth.

April 5 – the plants moved outside to the garden! We check the weather and make sure that we’re safe from extreme low temperatures at night from now on. One low night can kill the seedlings, so it’s better to be safe than sorry here.

This is a ever changing calendar, as some years are more mild than others. 2020 has been a very mild Winter and we moved the the plants outside on March 13, so you can see there is usually a few weeks variation from year to year.

To be extra safe, we cover the broccoli seedlings with garden fabric. This gives them a few extra degrees of comfort (and comfort for us knowing they’re ok!). If you notice we use jugs of water to protect from frost too (here’s more on how to protect plants from frost).

May 31 – We picked the first broccoli to eat from the garden! This is always a happy day!

How do you take care of broccoli seedlings?

Here are my favorite tips to take care or your broccoli seedlings:

1. Light. Make sure your broccoli seedlings are growing underneath a grow light. The most common mistake people make with all seedlings is not enough light and then you end up with “leggy” unhealthy looking plants. You will have to adjust with growth but place the light close to the seedlings but not so close that they burn (distance will be determined by how intense your lights are).
2. Soil. Use a potting mix for broccoli seedlings. Not a garden mix or garden soil. You want a light growing medium that will promote root growth and not easily compact. Seedlings will only grow to the size of their container and if they aren’t ready to be planted outside yet consider transplanting them into a larger container.
3. Germination. After you plant your broccoli seeds make sure to keep them in a warm spot free of cold drafts until they sprout. Cold soil temperatures will prevent or slow seed germination and may lead to complete germination failure. For best results consider using a temperature-controlled germination mat that will keep things at a toasty 75-85’F temperature. After sprouting the seedlings will not need such warm temperatures.
4. Water. Watering properly is crucial to healthy broccoli seedling development. It is very easy to overwater seedlings. You should only water your seedlings when the soil is almost dried out. If you see your seedling’s leaves turning yellow that is a sure sign of overwatering.
5. Wind. If you have a fan to place near your broccoli seedlings it can help with developing strong plants. We use a simple box fan for this. When outside plants are constantly assaulted by wind and weather and they grow strong to combat that. Indoors use can simulate that with a fan or even by brushing your hands over the seedlings a couple times. Be sure to monitor things closely with a fan because the soil will dry out more quickly.

Is Broccoli easy to grow?

Broccoli isn’t hard to grow, but it’s also not the easiest vegetable to grow. I wouldn’t say it’s the best beginner plant, but after a while you’ll get into a broccoli groove and be able to grow it successfully every year.

The hardest part of growing broccoli is knowing when to plant it, and when to pick it. Most broccoli doesn’t like extreme heat, so if you live in a zone that has a real summer, you’ll want to get it picked before the temperatures rise. Hot days will result in bolted broccoli that tastes bitter and noone wants that.

We live in NYC and we always try to have ours completely picked by mid June, and usually even that is a race across the clock. We try to time it just right before we have extremely hot days, and also knowing when our next plants need to move into the garden.

We have limited garden space in the city and mostly grow in sub irrigated planters. As soon as the broccoli is picked, a new vegetable will be planted right away to take over it’s spot – usually the next day. We try to keep the garden as populated as possible – more veggies means more food, which means more happiness!

How do you know when broccoli is ready to pick?

You can tell that your broccoli is ready to pick by the size of the buds. As the broccoli grows the buds will enlarge and if left alone eventually separate and open up to flower. You want to pick the broccoli before the plant flowers and need to pay close attention to the buds once they start to enlarge.

You can enjoy eating the broccoli when the buds are at any size but it makes the most sense to let them grow to their largest possible size.

….. Or when my daughter nibbles on it and tells me it’s yummy. Just kidding (although she does).

And if you find yourself with too many broccoli heads, here’s how to Freeze Broccoli for Long-Term Use.

What to do with broccoli leaves?

After you pick your broccoli use the leaves from the plant to make your own homemade vegetable broth. It’s a great way to use most of the plant. The broth can be canned or frozen for later use.

I hope this How To Grow Broccoli From Seeds post encourages you to grow your own food! Email me some pictures of your homegrown broccoli, I’d love to see them!

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