Bone meal is a dry, slow release fertilizer made from ground animal bones. Using bone meal for plumeria is one of the most debated tips in the hobby.
It is rich in phosphorus and calcium, the nutrient most growers link to flowers. Whether it actually helps your plant bloom depends mostly on your soil.
What bone meal is and what is in it
Bone meal is a byproduct of the meat industry. Bones are steamed, dried and ground into a coarse powder or fine granules. It is sold as an organic amendment, and it smells earthy to some people and rank to others.
The analysis on bags varies by brand. Colorado State University Extension lists bone meal at about 3-15-0.
Common retail bags show figures such as 3-15-0 or 4-12-0. That means a little nitrogen, a lot of phosphorus and no potassium, plus calcium from the bone itself.
Plumeria is a flowering plant, so the high middle number looks promising on paper. The catch is how much of that phosphorus your plant can actually use.
Does bone meal for plumeria help it bloom?
The honest answer is that it can help in some soils and do almost nothing in others. No controlled trial has tested bone meal on plumeria. What we have is general soil science plus grower reports.
The soil pH catch
Extension guidance says bone meal phosphorus is only available in soils with a pH below 7.0. In neutral to alkaline soil it stays locked up. The same source lists bone meal as not available in alkaline soils.
This matters for pots. Many potting mixes sit near neutral, and hard tap water can push the pH up over time. If your mix or water runs alkaline, the bone meal you add may simply sit there.
What growers report
Some experienced growers swear by it. A plumeria society newsletter described one grower who mixed bone meal into planting soil.
Her plants held their buds the following season. She noted other factors could have played a part, so treat it as a report rather than proof.
Others point out that bone meal is slow and gentle, so you will not see a quick change. Growers commonly say it works best as part of a steady feeding plan rather than as a bloom switch.
When it will not help
Plumeria often fails to bloom for reasons that have nothing to do with phosphorus. The big ones are too little sun, a young plant, an immature cutting or too much nitrogen.
Our guide to why a plumeria is not blooming walks through those causes. Our plumeria bloom guide covers the full picture.
Extra phosphorus is not always a good thing. A Washington State University horticulturist argues that most non farm soils already have enough.
She notes that excess phosphorus can suppress helpful mycorrhizal fungi. Bone meal for plumeria in the ground is best backed by a soil test, and a soil test is the way to settle it for in ground plants.
How slow is slow release?
Bone meal breaks down through soil moisture and microbes, so it works over weeks to months. CSU Extension gives a release window of roughly 1 to 4 months. Warm, moist, biologically active soil breaks it down faster than cool, dry or sterile mix.
That timing fits plumeria well, because the plant grows hard in warm weather. A spring application can supply phosphorus through the main growing season. It will not help a plant that is dormant and cold.
How to use bone meal on plumeria
Treat your brand’s label as the starting point for bone meal for plumeria. Rates differ between products, and the label is the only rate that matches the analysis in your bag. The steps below are general practice, not a tested plumeria rate.
In pots
- Water the plant lightly the day before so the roots are not dry.
- Measure a small amount, following the label rate for the pot size. For a typical one to three gallon pot, growers commonly use a tablespoon or two. That is a rule of thumb, not a sourced figure.
- Scratch it into the top inch or two of mix, keeping it away from the trunk base.
- Water it in well. Cover the surface with a thin layer of mix so animals are less tempted.
Repeat no more than once or twice in a growing season. Our container growing guide and pot comparison help with the mix and pot side of the equation.
In the ground
For in ground plants, work bone meal into the soil around the drip line, not against the trunk. Apply it once in spring, then water it in. For a new tree, you can mix some into the backfill, as covered in our planting guide.
Do not go heavier because the plant is slow. Excess phosphorus does not make flowers bigger, and it can cause problems of its own. Always check the label and start at the low end.
When to apply it
Early spring, as growth begins, is the usual time. A second light dose in early summer is fine if the first has had time to work. Skip it in fall and winter, when a dormant plant is not taking up nutrients.
Risks and downsides
- Dogs and other animals: The smell attracts dogs, raccoons and rodents that dig. Eating it can upset the stomach, and very large amounts may trigger pancreatitis in susceptible dogs. Check the bag, since some bone meal is mixed with an insecticide.
- Odor: A fresh application can smell, especially in a warm, moist pot. Burying it and watering it in helps.
- Cost for the benefit: Bone meal costs more than many general fertilizers for the nutrient you get.
- Hands and dust: Wear gloves and avoid breathing the dust.
If you have dogs, the plant is a separate worry from the fertilizer. We cover that in our article on plumeria and dogs.
Bone meal or a regular plumeria fertilizer?
Bone meal is a supplement, not a full feed. It has almost no potassium and little nitrogen, so it cannot carry a plant alone.
Most growers pair it with, or replace it by, a balanced high phosphorus plumeria fertilizer. Those also supply micronutrients.
Our plumeria fertilizer roundup compares those options, and how and when to fertilize plumeria covers timing in detail. If you would rather make your own, see homemade plumeria fertilizer.
Where to buy
Bone meal is sold at most garden centers and online. Look for a clearly labeled analysis, such as Espoma or Down to Earth.
Check that it is plain bone meal without added insecticide. According to the label, most are meant for mixing into soil rather than top dressing.
If you want a ready made plumeria feed instead, a high phosphorus formula is simpler. Nelson plumeria plant food is a common choice according to its label. It avoids the pH and smell issues.
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Frequently Asked Questions
Can I use bone meal on a plumeria cutting?
Not until the cutting has rooted and put out leaves. An unrooted cutting cannot take up nutrients, and fertilizer near it can add rot risk. Wait until it is growing strongly.
Is bone meal better than a bloom booster fertilizer?
Not clearly. A bloom booster is soluble and acts faster, while bone meal is slow and depends on soil pH. Many growers use a booster for quick results and bone meal as a gentle background source.
How often should I put bone meal on plumeria?
Once in spring is plenty for most plants, with an optional light second dose in early summer. Follow your product label. More frequent use mostly adds cost and the risk of excess phosphorus.
Can bone meal burn plumeria roots?
It is much gentler than most synthetic fertilizers. A heavy pile against the trunk is still a bad idea. Mix it in and keep to the label rate.
Is bone meal safe around dogs?
Not entirely. It smells appealing to dogs, and eating a lot can upset the stomach. Bury it, water it in and keep the bag out of reach.