Optimal Temperatures In A Greenhouse For Petunias

Are you aware of what are the optimal temperatures in a greenhouse for growing petunias? It can be confusing at first because they differ for every growth stage. However, many university extensions are generous in sharing information for planting, rooting, and growing petunias in the greenhouse. 

The effectiveness of a greenhouse in growing plants will only be possible with the practice of each plant’s ideal conditions. One of the significant factors that you have to maintain in growing petunias in the greenhouse is the temperature. Upon meeting these requirements, you can reap the benefits of greenhouse gardening amidst the conditions outside.

What Are The Optimal Temperatures In A Greenhouse For Growing Petunias


What Are The Optimal Temperatures In A Greenhouse For Growing Petunias: Gardener’s Guide

Below are different temperatures for planting, rooting, and growing petunias. You must maintain the greenhouse in these conditions and adjust accordingly, depending on your growing zone. The Missouri Botanical Garden mentioned that these flowers grow well in zones 10 to 11, so study your area’s rating beforehand. 


Optimal temperatures for planting petunias

According to Iowa State University, you can start your petunia seeds in containers, but it’s crucial to maintain the location at 75 to 80°F for optimum seed germination. High temperatures above 90°F and direct sunlight can prevent germination. Once the seeds germinate after 7 to 10 days, the temperatures should be at 60 to 65°F. 

Greenhouses are excellent for those who want to grow petunias from seeds since outdoor planting is more natural with transplants. But what are the optimal temperatures for petunias if you’re transplanting them from the greenhouse to the garden? The University of Minnesota Extension recommends waiting for the soil to warm up at 60°F to avoid damages from frost.

Besides, remember to lower the night temperatures at 63 to 65°F to prepare them for transplanting. Speaking of soil temperatures, Utah State University noted that maintaining the growing media in the greenhouse at 65 to 75°F, or 70 to 72°F in particular, leads to successful seed germination. In the greenhouse production of petunias in Auburn University, you can also maintain 75 to 78°F for the first five days, 68 to 75°F once you see cotyledons unfold, then 65 to 70°F when you see the real leaves. 

And for the irrigation and mist in the greenhouse, use water at 70°F.


Optimal temperatures for rooting petunias

Sometimes, gardeners prefer rooting petunias instead of growing them from seeds. In this method, you want to root the plants for 2 to 3 weeks between 64 to 75°F. The advantage of rooting or using cuttings is that the plants you’ll grow are similar to the original and will bloom earlier. 


Optimal temperatures for growing petunias

For growing and maintaining petunias in the greenhouse, remember the numbers for day and night temperatures. During the day,  the temperatures should be 64 to 75°F and 55 to 64°F at night. However, there are some cases where petunias are hardy even at 95°F

Did you know that the plant height, flowering time, and lateral branching of petunias are affected by temperatures? Between 50 to 77°F, the highest temperature can make taller plants, hasten to flower, and lessen lateral branches. And if you have just transplanted petunias, experts recommend using 63°F for ten days first. 


Other Greenhouse Requirements For Growing Petunias

Besides temperatures, there are some guidelines that you must meet with petunias in the greenhouse. Remember to use a light, well-drained soil with average fertility at a pH of 6.0 to 7.0. And for hardening petunias from the greenhouse to outdoor beds, use a sheltered area to help them adjust. 

Once petunias are established, give up to 2 inches of water every seven days. Monthly feeding using a balanced fertilizer will also encourage growth and blooming. If your petunias stop flowering, prune the shoots but do not remove all of the leaves.

Using a liquid fertilizer and watering well will help with flowering. As for deadheading, double petunias and those with large flowers require removal of old and dying flowers. If you’re using cultivars with smaller flowers, they will usually do this themselves. 

What problems can you expect in growing petunias? The good thing with this flower is it has a few issues such as aphids and slugs. Proper watering and humidity control can also address petal blight and other diseases. 


What Is The Best Petunia For Greenhouse?

The Grandiflora singles, Multiflora singles, and their double flower forms are the most famous horticultural types of petunias. Grandiflora has large flowers, and many cultivars offer a wide range of colors, but the smaller Multiflora can withstand demanding conditions. 



Many university extensions have written about the convenience and advantages of growing and producing petunias in a greenhouse. But do you know what are the optimal temperatures in a greenhouse for growing petunias? This is a crucial question as the greenhouse temperature plays a significant role in the success of petunias. 

Each growing stage, whether during planting, rooting, or growing, has different temperature requirements. Failure to meet them can affect the germination, growth, and quality of your petunias. In general, 64 to 75°F at day and 55 to 64°F at night are best for growing petunias in the greenhouse. It would also help that you learn your planting zone to know the temperatures to expect in your area. 

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How To Prevent Root Rot In Hydroponics: 3 Useful Tips

If you’re a newbie gardener who’s looking to find ways to hone your skills, you’d want to learn how to prevent root rot in hydroponics even before this problem affects your plants.

Hydroponics can be advantageous to crops in more ways than one. However, it also comes with risks of diseases, such as root rot, which can be destructive or even lethal to your plants.

Unfortunately, there are no effective methods to recover the wilted parts that were affected by the root rot once it hits your plants. The only thing you can do if you do not want this catastrophe to befall your crops is to prevent it before it happens. Read on to learn more about this subject.


What is Root Rot?

Root rot is a disease that attacks the plant roots and causes them to suffer decay. This usually happens when a lack of oxygen supply occurs in the substrate.

To give you an idea, think about plant roots that are submerged in water that only has a little oxygen in it. Over time, the plant suffocates and dies.

Aside from rot and decay, this disease also leads to the proliferation of fungi that are naturally present in the soil. These include Rhizoctonia, Alternaria, Pythium, Botrytis, Fusarium, or Phytophthora. As soon as fungi colonies start to grow, they tend to target the weakened roots and infect your precious plant babies.

Once the plant becomes infected, they won’t be able to take in what they need to grow – water, oxygen, and other nutrients. When this happens, it won’t be long before the plant dies.


What is Hydroponics?

In case you’re not aware, the term hydroponic is derived from a Latin word that means “working water”. To put it simply, hydroponics is an art that involves growing various types of plants without soil. If you’re like most people, the first thing that comes to mind when somebody talks about hydroponics would be a picture of plants with roots suspended into the water without using any type of growing medium.


Avoiding Root Rot in Hydroponic Systems

Detecting and identifying root rot can be tricky. When your plants get infected, their leaves and roots gradually wither until the whole crop itself dies from the lack of nutrients, which is a common symptom of many diseases.


What causes root rot in hydroponics?

One of the requirements in hydroponics systems is oxygen. Without it, your plants are basically on the road to death. On the other hand, lack of such is one of the major triggers for root rot, and it must be avoided at all costs.

Just like when planting in soil, you loosen up the ground so that your plants’ roots can have their required intake of oxygen. That is the case for crops grown in aqueous solutions as well. If they cannot breathe, they would not be able to grow.

Another agent for root rot is the temperature. The last thing you would want in your system are parasites that leech nutrients intended for your plants and infect the water during the process. In common terms, these fungi are called molds.

One of the best breeding grounds for these is warm and moist areas. For this reason, if the water temperature inside your reservoir is high, then you are susceptible to it. Something as minor as letting the solutions exposed to sunlight can already be a risk factor.


3 Useful Tips on How to prevent root rot in hydroponics

There is good news! Root rot in hydroponics can be prevented! Just follow these tips:

Tip#1: Use the right air pump

If you do not want root rot to affect your plants, you merely have to avoid its causes. If you need oxygen, keep the water bubbling by providing an air pump of appropriate size, and also give importance to proper ventilation in the room.


Tip #2: Maintain the temperature

The temperature should be maintained within the 70 to 80 degrees F range. Get rid of any materials that can make your system vulnerable to infections, and make sure not to disturb your crops while they are trying to grow.


Tip #3: Get rid of the rotten parts

However, if you failed in preventing the disease, then the rotten parts should be removed immediately. Cut them off as there is no chance of reviving them, and focus on the potential new growth instead. Fix your hydroponics system and eliminate the risks.


Why Give Greenhouse Gardening a Try?

Greenhouse gardening offers numerous benefits to greens aficionados who dare to take their gardening experience to the next level. Aside from acting as a shield against the effects of inclement weather, a mini, hobby, or semi-pro greenhouse can also serve as a protective layer that keeps harmful bugs and critters at bay.

What’s more, its enclosed structure allows you to control your plants’ growing conditions including the temperature, light, moisture, and ventilation of the greenhouse’s internal environment. With a controlled environment, you’ll be able to extend growing seasons and grow plants that aren’t native to your area.



No matter how well-informed you are about how to prevent root rot in hydroponics, you cannot completely eradicate the risks. Therefore, to avoid the worst-case scenario, you should be prepared to sacrifice the infected for the sake of others. While you’re at it, consider trying your hand at greenhouse gardening as well.


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