Light from sun is used by plants to produce glucose from carbon dioxide and water.
Lack of sunlight impact the broccoli head and produce leggy plants. However, this cool-season crop can’t tolerate high temperature.
So, how many hours of sunlight is ideal for growing broccoli?
Broccoli needs 6-8 hours of sunlight to thrive and produce healthy broccoli heads. But, remember too much heat can ruin the yield and this plant can’t survive in hot days.
Does Broccoli Need Full Sun?
It’s easy to determine how much sunlight a plant needs, you get it on the label, the real difficulty is in confirming that your yard gets enough sun exposure or not.
Full sun means, getting sun exposure for at-least 6 hours. Though in some cases it can also be more than 8 hours, depending on the plant you choose.
When you read broccoli needs full sun, remember that it needs 6-8 hours of sunlight.
As this is cool loving crop, most gardeners plant broccoli seeds in spring for early summer harvest. Or start planting in late summer for harvest in fall.
This is to avoid high temperatures, because heat can make the plant leggy.
Broccoli can also grow in partial shade or partial sun. As long as the plant gets 6 hours of direct sunlight, it continues to grow and produce better yield.
In case, if you see leaves are turning yellow or the plant being thin. This can be the sign that your broccoli isn’t getting enough sunlight.
I recommend you to read further to know about sunlight requirements of your broccoli.
Check this article: How to Grow Broccoli Microgreens?
Importance of Sunlight for growing Broccoli
Three most important things to grow vegetable plant like broccoli are location, location and location.
Planting spot with abundant sunlight well drained soil and away from shrubs is what helps your plant to thrive.
Without sunlight you can’t grow vegetables irrespective of how rich your soil is. There is no vegetable plant that you can grow in backyards with zero sunlight. (Source)
Plant leaves take light from sun to transform carbon-dioxide and water to sugar. Leaves that don’t get enough sunlight turn yellow and drop.
Your plant gets its green color from chlorophyll, lack of sunlight break this compound and the foliage turns yellow.
How Much Sunlight Does Broccoli Need?
Above I already mentioned that broccoli needs full sunlight, which is 6-8 hours of sun exposure.
But, what happens to your plant when it gets exposed to harsh sun for 8 hours. As a cool-season crop, can it tolerate the high temperature?
What is a Cool-Season Crop?
As the name suggest, cool season crop is a plant that does well in cold temperatures for instance 70F or below. These plants can also tolerate light frost.
Key to grow broccoli is to reach maturity in cooler temperatures. If at all your broccoli doesn’t mature before warmer climate, then the raises temperature may ruin the yield.
Important: Just because they love cooler temperatures, don’t mistake they can survive hard freeze or frost. You must plant broccoli when the soil temperature is about 40F or 2 weeks before the last frost. (Source)
- Almanac.com states that broccoli thrive when the temperature is between 65F to 70F.
- Soil temperature as mentioned above must be 40F.
Apart from 6-8 hours of sunlight, broccoli plant needs soil that is fertile and drains well. No plant would like to stand wet; overwatering often results in root rot, yellow leaves and stunted growth.
Before planting, it is important to know how often to water broccoli plant.
Feed the plant after every three weeks with fertilizer with 5-10-10 NPK ratio.
Also read: How to Propagate Broccoli?
What happens to broccoli if it doesn’t get enough sunlight?
Lack of sufficient sunlight may result in yellow leaves, stunted growth, thin leggy plant and subpar broccoli heads.
Unlike indoor plant that can survive in low lights, edible plant like broccoli doesn’t thrive in shade.
However, you can grow them in partial shade and still get good yield.
How to revive?
If you see the broccoli plant is suffering from insufficient sunlight, then shift the location if you’re growing them in container. Else, you must remove the trees or plants that are blocking sunlight from broccoli.
This is why you must give utmost priority towards the location. Without adequate sunlight you can’t plan to grow successful broccoli.
Check this article: Why Are My Pumpkin Plant Leaves Turning Yellow?
How to Grow Broccoli in Partial Shade?
Some plants like full sun and some prefer shade. Broccoli plant is among the plant that can be grown in partial shade or partial sun.
Are you living in concrete jungle where it is difficult to get 7 hours of sun exposure? Should you stop dreaming of growing vegetables in containers, because you can’t give them adequate sunlight?
No, fortunately you can still grow broccoli in partial shade. But let me confess that the quality of yield can’t be compared to those plants that get enough sunlight.
- Germinate and grow broccoli seedlings indoors under grow light or beside windowsill.
- Use coco peat to grow broccoli seedlings.
- When the seedlings reach certain height, before transplanting prepare the pot or bed.
- Prefer the location in your garden that gets sun exposure for longer time. Let’s say at-least 3 hours. However, 6 hours is recommended for healthy broccoli.
- Soil must be well drained and mixed with aged old compost.
- Plant young broccoli to raised bed or 8 inch deep container.
- Water gently and add organic compost every 3 weeks to plant.
- Harvest when the broccoli head reaches 1 inch in diameter.
Make a way for sunlight by removing branches of trees that are near broccoli. More the sunlight reaches your plant, quicker the vegetable matures.
Or you can also plan to grow broccoli in container and shift them to location where it gets 6 hours of sun exposure. This way you can get quality yield even without a backyard.
Growing Broccoli in Summer and Heat
University of Massachusetts Amherst states that most gardeners don’t prefer growing broccoli in hot summer, because it will eventually results in poor quality yield.
This is why broccoli must mature before hot summer reaches or plan to grow this plant in late summer.
Preferred temperature to grow this vegetable plant is 60F to 70F.
To protect your plant from harsh summer, you can use shade cloth, water the plant frequently and use mulch.
Mulching helps to reduce the soil temperature to some extent. Also it will reduce the water evaporation.
Knowing how many hours of sunlight does broccoli needs, will help to grow successful plant. As low levels of light can result in rotting of broccoli head or poor yield.
Location is most crucial factor when you’re planning to grow vegetable plant.
A spot that gets 6 to 8 hours of sunlight is ideal to grow broccoli plant.
Apart from this you must remember that this edible plant can’t tolerate high summer temperature. However, it can withstand little frost and does well in 60F to 70F temperature range.
Well drained soil, water, fertilizers are as important as the sunlight to grow broccoli plant.
Apart from this, you should check out the diseases and pests that commonly attack this plant. For instance, cabbage worms and aphids are buildup under the leaves. Try organic pesticide available in the market or try neem oil to get rid of these common pests.