Want to keep your petunias blooming strong, beautiful and vibrant – and get those flowers to keep on coming and last all summer long? Believe it or not, it really is possible by simply using a few basic growing tips that work like magic!
Petunias are one of the most popular summer annuals of all for growing in containers, hanging baskets and flowerbeds. From trailing varieties to wave petunias and more, they can be found in a near endless variety to fill almost any need or space. Especially when you consider their wide range of colorful blooms!
But, as with many annuals, gardeners often find their petunias beginning to struggle by summer. Plants once loaded with blooms and flowers begin to have trouble just keeping their foliage from turning brown.
Sadly, without help, within a few weeks of the first signs of trouble, plants simply wither away. And just like that – you either have to buy more petunias – or have do without all of that fabulous color until next year.
The good news? It doesn’t have to be that way! In fact, when it comes to keeping petunias thriving all summer long, by simply following four simple tips, you can all but ensure your petunias will last and keep on flowering right up through fall.
How To Keep Petunias Blooming – 4 Secrets To Make Petunias Last!
#1 Buy Small Plants In Large Containers
When trying to get your petunias to last, especially when it comes to petunias growing in pots or hanging baskets, the first and most important key of all is to not purchase overly large plants in early spring.
Unfortunately, although big, flowering plants may look great to bring home in the spring – they simply won’t last. Not in their current container anyway. One of the most common reasons petunias growing in baskets and containers fail is their roots become root bound.
Plants that are large and flowering in May already have massive roots. And within as little as a month, the petunias will begin to fail unless you repot to a larger space. It’s far better to start with smaller plants – and make sure they are growing in large containers.
Avoid baskets and containers that are smaller than 12 inches in diameter. They just don’t have the room for all-season root growth. And if planting your petunias in beds, make sure to allow plenty of space between plants to grow together.
#2 How To Fertilize Petunias To Keep Them Blooming
Equally important for keeping petunias flowering is fertilizing. But how, when and what you use to fertilize is a huge factor in how long and well they will bloom.
Petunias need a slow and steady diet of nutrients to keep producing blooms and flowers. As a heavy flowering annual, they can quickly deplete the resources available in the soil around their roots. And without replenishing those nutrients, they will begin to slowly weaken over time.
But the real secret to long term success is how and when you replenish those nutrients. Unfortunately, many fertilizers provide too much power too quickly. Or even worse, the wrong kind of power for blooming.
Listen In Below To Our Podcast On The Secrets To Fertilizing Hanging Baskets For Big Blooms!
If you feed your petunias with too much power, they will use it all to grow larger roots and foliage. It can quickly lead to root bound plants that overgrow their space.
One of the biggest culprits of this is using a fertilizer with too much nitrogen. Nitrogen greens up plants and causes massive growth, but it’s not vital for blooming. All of that power leads to too much growth way too fast. It’s simply not sustainable for the plant. Especially when there is limited soil space when growing in containers and hanging baskets.
Using The Right Fertilizer For Petunias – In The Right Way
For long lasting plants and blooms for petunias, a slow and steady approach with a fertilizer that is more heavy with phosphorous and potassium than nitrogen (N-P-K) works wonders. Why? Because phosphorous and potassium are the key nutrients to help power blooms – but won’t overgrow your petunias.
Use a liquid fertilizer with a ratio of phosphorous that is triple to nitrogen. And make sure there is a good double dose of potassium versus nitrogen as well. Affiliate Link: Jack’s Classic Blossom Booster 10-30-20 Water Soluble Plant Food
The final secret when fertilizing is to fertilize more often – but at a diluted rate. Again, it’s far better to give petunias a slow and steady boost of nutrients to keep them in top shape – in place of a bigger burst far apart.
For long lasting and beautiful blooms, aim to fertilize your petunias every 10 to 14 days – but dilute the fertilizer to 1/4 or 1/2 of the recommended rate. This little trick is a big one to keep your petunias looking awesome all summer long!
#3 Watering Petunias – How Keep Petunias Blooming
Improper watering also often plays a key role in the demise of petunia plants. And that can be both failing to water regularly – or watering way too much. In fact, of the two, overwatering is usually the biggest culprit to plants failing.
If the roots of petunias sit in water, they swell. And when they swell, they can’t absorb water or nutrients. The result? They turn yellow, stop blooming – and eventually fail. The same goes for underwatering. The roots shrivel and once again cannot take in nutrients.
So how much water is enough. The answer all comes down to the moisture in the soil at the root level. The soil should be slightly moist or damp, but not saturated. Most pots and containers will need water once a day, bedding plants usually every three to four. But to know for sure – check the soil moisture!
The good news is it’s easy to do with an inexpensive soil meter. Simply stick the probe down into the soil and you get an instant read of the moisture level. It literally takes all the guesswork out of when to water. It’s actually a great tool to use for proper watering everywhere! Affiliate Link: Instant Read Soil Moisture Meter
#4 Deadheading Old Blooms – How To Keep Petunias Blooming All Summer
Last but not least – deadhead your spent petunia blooms on a regular basis! Not only do old blooms look unsightly on plants, they also rob it of vital nutrients. As with most annuals, petunia plants continue to spend resources attempting to heal and fix old blooms. Resources that instead could be used for producing new blooms and flowers.
Deadheading (the process of removing spent flowers) your petunias is one of the best ways of all to keep those flowers coming on. By simply taking off the older blooms that are beginning to fail, the plant can concentrate all of its energy on growing healthy foliage and more flowers. And it couldn’t be easier to do!
Petunias happen to be one of the easiest of all annuals to deadhead. There is no need to cut stems or use tools of any kind. Simply give a slight pull to an old flower and it instantly dislodges from the plant.
Deadhead your plants every few days and you will be amazed at how much energy the plant retains throughout the growing season.
Re-Potting Petunias – How To Keep Petunias Blooming All Summer
If your plants do become root bound, you will need to replant them if you want them to continue to survive and flower. And the quicker you do it at the first sign of trouble, the more chance your petunia plants will have to keep on flourishing
When replanting, always try to select a vessel that is 2 times as large as the original. This will allow plenty of space for petunias to stay strong for the remainder of the season. And if your plants are simply too big for a new pot or basket, just plant them directly into a flowerbed!
You will be amazed at the renewed energy and life the petunias will have from new soil. Here is to keeping your petunias blooming strong all summer long – Happy Gardening! Jim and Mary
Old World Garden Farms
Jim and Mary Competti have been writing gardening, DIY and recipe articles and books for over 15 years from their 46 acre Ohio farm. The two are frequent speakers on all things gardening and love to travel in their spare time.
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