Petunias like full sun so the more they get the more flowers they will grow. Grow a huge display of petunias within a week of planting by choosing a position that gets 8 hours of summer sun and regular water. Planting petunias in good quality, well draining soil and adding extra liquid fertilizer will help the plant grow up to 5 times more flowers than those grown in shade.
This article will explore all you need to know about growing petunias in sun and shade and tips for growing more flowers.
Will petunias grow in shade?
Petunias will grow in shade but you will get less flowers than those grown in sun. If the only position you have is in part shade then I would still go ahead and plant petunias but expect less flowers than those in a full sun position.
Another great option is to plant petunias in pots and you can move them around to a sunny position as the season changes. I have planted some petunias in a pot at the front of my house which means I can move them into a paved area, move them into a sunny corner or place them near my door for a bright feature.
Within 2-3 weeks these petunias will be covered in flower like those I planted 2 weeks earlier. I like to opt for new hybrids that will cover a large area and be covered with flowers. These offer the best value for money and can cover up to 2.5 feet.
How to grow more petunia flowers in full sun
Here are the benefits of planting petunias in a full sun position and a large, healthy plant and tons of flowers.
Plant petunias in good quality soil
To get a full coverage of flowers on your petunias grown in full sun make sure you plant them in the best soil possible. For raised garden beds choose a raised garden bed mix and mix through chicken manure or aged cow manure. This mix will be free draining and full of nutrients for fast plant growth.
When planting petunias in the ground it will be beneficial to mix through compost or aged animal manures to boost the nutrient value. You can mix through pelted chicken manure with a fork to feed the plant for up to 3 months.
Water petunias regularly
Petunias will grow rapidly and be covered with flowers if they are watered regularly. I like to water petunias every 2 days for the first week and slow down the watering after this to every 3-4 days. Hanging baskets will need regular watering as they will dry out quicker, particularly in full sun.
Potted petunias in full sun will also dry out quicker than those grown in raised garden beds or in the ground. Mulch petunias with bark mulch to reduce the evaporation of the water from the soil. You can also mulch the top of potted petunias as this will also help to keep moisture in.
Add seaweed solution and nitrogen fertilizer
Topping up petunias with seaweed solution and a liquid nitrogen fertilizer will keep the plants healthily growing flowers over 3-4 months. Growing flowers uses up a lot of nutrients so the petunias will need these replaced. Liquid fertilizer can be given to your petunias every month.
Liquid nitrogen fertilizers like fish emulsion will replace these quickly and the plant can rapidly absorb them, Add some slow release fertilizer like pelleted chicken manure for a slower delivery of nitrogen to the plant. You will need to do this less often as it will last for up to 3 months.
Deadhead flowers as they grow
Petunia plants that grow lots of flowers will need to be deadheaded frequently to keep them growing strong and renewing their flower coverage. Pinch off old flowers with your finger tips to encourage the plant to send out new flower heads.
If old flower heads are left on the plant the petunia can reduce the new flowers it produces. Pinch off old flowers as soon as they start to droop and this will free up more space for new flowers and more sunlight will reach the plant.
Choose a petunia that spreads and grows large
There are many types of petunias to choose from but my favorites are the large spreading ground covers that can grow up to 2.5 feet wide and be covered with flowers. New hybrids offer a range of bright colors including ‘hot pink’ which can brighten up a full sun position.
Grow petunias in gaps in your garden beds and let them scramble and fill the space with bright, annual flowers. At the end of summer you can pick them out and replace them with fall annuals.
Can petunias get too much sun?
Petunias really can’t get too much sun but can dry out if they are not properly mulched and watered. On hot summer days, make sure the bark mulch around them is around 2 inches thick and water them well in the morning.
Petunias in shallow pots or hanging baskets may need an additional water at the end of a hot day. Check to see if the flowers or leaves are drooping and water them if needed.
How do you keep petunias blooming?
Keep petunias blooming by adding a dose of liquid nitrogen fertilizer each month over the growing season. Surround them with mulch to keep the water in the soil and water them every 3 days to keep them happy.
Water in the morning to make sure that the plant is hydrated and prepared for hot sunny days. You will be rewarded by a rapid show of bright flowers covering the plant.
How many hours of sunlight do petunias need?
Petunias will thrive with at least 6 hours of sunlight. They will produce the most flowers possible with 8 hours of bright light but can still thrive in a part shade position. Plant petunias in pots if you have a shady yard and place them near your front or back door to find the most sun.
How long do petunia flowers last?
Petunia flowers last for up to a week before they will start to droop. You can pinch them off and the plant will quickly replace them with new ones. Water the plant well in the morning and add a slow release fertilizer to keep them fed over the growing season.
Do petunias like sun or shade? | Summary
Petunias love full sun and will grow the most flowers possible if they get more than 6 hours of bright light. Any more sun will give you more flowers and expect those with the most sun to outperform those grown in shade.
Petunias grown in full sun can grow up to 5x more flowers than those grown in shade.
I am an accredited practicing dietitian, experienced gardener and a dedicated cook. I love writing and sharing my experience so you can learn from my successes and mistakes.