How important is pH for Germination Plumeria Seeds

Growing Medium and Water PH

The success of plumeria seeds always starts with the condition of the medium used for germination. One of the most important properties to keep tabs on is your pH levels for the medium and the water.

What is pH?

pH is a numerical rating of its acidity or alkalinity. All pH is measured on a logarithmic scale from zero (most acidic) to 14 (most alkaline or basic). In chemistry terms, when you measure pH you are essentially measuring the number of hydrogen (H+) ions in a solution.

Why does pH matter?

If you search the web you will find quite a few different opinions regarding the importance of checking the pH. However, we urge you not to ignore soil pH. Determining the pH of the germination medium and water is essential to determining how available soil nutrients will be to your seeds when they germinate. Achieving the optimum pH for your seedlings will allow them to absorb nutrients more effectively. If you germinate your plumeria in a medium outside of its preferred pH range you will most likely see poor growth and eventual blooming and your seedling may even struggle to survive.

What affects pH?

Soil pH varies with climate, as well as physical surroundings.
For example, climates with dense forests such as those along the Pacific Coast will have acidic soils with pH ratings of about 4.0-5.5. Arid regions, such as the Rocky Mountain regions, will generally have soil pH levels that are closer to neutral ranging from 6.0- 6.5 and regions such as South Florida will tend to be more akaline above 7.0. Keep in mind that even these general ranges are subject to variability.

However, the good news is when you purchase a seed germination mix, most are pH neutral around 7.0

What is ideal pH for growth?

All plant species require their own unique pH to achieve optimum growth. For most plumeria you will want to aim for a pH level between 6.5-6.8 (slightly acidic) for optimum nutrient uptake.

How can you obtain optimum pH?

There are a variety of techniques that may adjust the pH of your soil.

Note: If you need to adjust your pH, use small amounts when adjusting the nutrient solution to affect the pH level, as required. Apply to the soil by mixing the product with water. Make sure to check the pH of your mixture before adding it to the soil. For best results, check the pH level daily.

Maintaining pH

Why is Checking pH Important?

Among the growing community there is debate on the importance of checking and maintaining pH. We urge you not to ignore the pH of your germination medium, whether your medium is plugs, soil, or water. Determining the pH of your medium is essentially determining how available nutrients will be to your plumeria. Achieving the optimum pH for your plumeria will enable them to absorb nutrients more effectively. If your seed germination medium is outside of the preferred pH range, you will most likely see poor growth and your plumeria may even struggle to survive.

What if I Don’t Check pH?

Many successful crops have been harvested without ever checking pH, but we don’t recommend going that route. Having an optimal pH will allow your plumeria to absorb maximum nutrients and your seedlings will grow and mature sooner and to their fullest potential.

Failure to check your pH can cause a variety of problems. You may be overfeeding your seedling, and this could put your plants at risk for nutrient burn You may also misdiagnose a problem as a nutrient deficiency, when in fact the problem is not the amount of nutrients, but the ability of the roots to absorb the nutrients.

Remember, nutrients can be costly, and if you are overusing them to make up for unbalanced pH levels then you are basically throwing money down the drain.

How Often Should I Check pH?

When growing plumeria seedling in soil, you should check the pH every few weeks to ensure levels are remaining stable. Due to hydroponic systems being more sensitive to pH changes, it is important to check the pH of your water more often.

Types of pH Kits

There are several types of pH testing kits available on the market today. Learn more about the different types below to determine the best kit for your growing conditions. 

Test Strips

To use in soil, you will have to make a mixture of soil and distilled water that is about the consistency of a milkshake. Place the strip in the solution and wait for the color to change. Compare this color with the color chart on the bottle, and will be able to tell what your pH is. To test your water, you can just dip the strip directly into your water.

Chemical Solutions (AKA Dropper Kits)

To use, place some of your soil in a vial, add distilled water, and then apply the amount of chemical solution as per the instructions. This will give you a color that you can compare to the attached chart.

Digital pH Testers

Digital pH pens offer a precise way to measure the pH of your water or soil. You will need to make a solution with your soil and distilled water. No need to squint at a color chart with a pH pen, you simply look at the number on the screen.

Would it be better to take a pH reading of the soil directly?

Sure would! This is trivial at the top of the soil, pulling out a sample at the bottom of the pot is a bit more involved. As we know, they may not have a consistent pH between them. In some cases, that could be a very different reading.

Extreme pH readings

If you have extreme pH readings, bad things are happening. Seeing a pH that is more than 1.0 from your input target is cause for alarm when you see any indication in the plant. This usually indicates over/under feeding, bacterial infection, large amounts of media buffers present, or some lesser-likely issues.

Coco Coir is the classic example of this. If you feed regularly, but don’t run enough solution through to dissolve and remove some build-up from past feedings, nutrients accumulate. Since these nutrients are mostly acidic mineral salts, they drop the pH of the plant. By the time you notice, the pH has hit an extreme enough level that you need to act fast.

Fixing this particular case consists of flushing the plant and giving light feeding for a little while. After the media environment stabilizes, you can increase the feed schedule. Additionally, you should run more nutrient solution through to prevent build up, or add a flush in the schedule.

Extreme pH fluctuation going alkaline is a sign that you are greatly underfeeding your plant, or could be a bacterial infection. This is far more rare, but just as deadly. The solution is to determine the cause, and attack that problem.

Sources:

  1. https://www.extension.umn.edu/garden/landscaping/implement/soil_ph.html
  2. https://www.extension.iastate.edu/article/yard-and-garden-soil-ph-and-testing
  3. https://www.motherearthnews.com/organic-gardening/gardening-techniques/soil-ph-zm0z14amzkin
  4. https://phet.colorado.edu/en/simulation/ph-scale-basics
How important is pH for Germination Plumeria Seeds

Fertilizing New Seedlings

Fertilizing seedling is very important to development and growth. Fertilization should begin soon after your seedlings grow their first “true” leaves. The first leaves that emerge from the seed are called the cotyledons. They’re rounded with smooth margins. The second set of leaves to develop is the “true” leaves. They look very similar to the foliage of the mature plumeria. When the first 2 sets of “true” leaves have fully emerged, it’s time to start providing your seedlings with nutrients and move your seedlings to the next stage in their care.

When the “true” leaves arrive, your seedling will have developed roots and need nutrients and sun to help convert the nutrients into plant food. There are lots of different potting mixes you can use, but I suggest ones that contain 1/3 pine bark, 1/3 peat, 1/3 perlite with Mycorrhizae. Potting soils with nitrogen will cause your seedlings to grow lanky. Lack of sunshine will also cause your seedlings to grow lanky

When you transplant your seedling into pots, it’s time to begin fertilizing with a balanced granular fertilizer containing micro-nutrients. I suggest slow-release Excalibur 11-11-14 or similar.

Suppose your seedlings get stressed from heat, too much rain, or insects. It’s beneficial to use a quick-release granular fertilizer or a liquid fertilizer. I suggest Excalibur BOOST 10-12-14 or Bioblast 7-7-7. You can use Excalibur BOOST every two months and Bioblast every two weeks. Choose a product formulated for use on seedlings.

If you haven’t started your seedlings in full sun, you will need to introduce them gradually. Begin by placing them in a shady spot outdoors for just a few hours. Slowly leave them outside for more extended periods and expose them to more sunlight until they are in full sun for at least 6 hours per day. This hardening off process is significant to young seedlings and helps them gradually adjust to brighter light levels, wind, and fluctuating outdoor temperatures.

NOTE: If you live in a region with extremely hot temperatures you may need to use shade cloth or less exposure to the hot sun.

Fertilizing New Seedlings